Nanometer dosage measuring device, system and method

Abstract

The invention relates to a nanodose measuring device, system and method. The nanodose measuring device comprises a main frame body and an electric field insulation protection structure, in the electric field insulation protection structure, a cavity is formed in the center of a high-voltage protection assembly, and a high-resistance dielectric plate is arranged on the outer side of the bottom of the cavity; the high-voltage insulation assembly is provided with a negative high-voltage cathode feed channel penetrating through the high-voltage insulation assembly, so that the non-penetrated part of the high-voltage insulation assembly forms a blocking part; the edge parts of the high-voltage protection assembly and the high-voltage insulation assembly are nested with each other, and the high-voltage protection assembly and the blocking part form an insulation space body wrapping the negative high-voltage cathode feed channel; the cathode vacuum cover plate is sleeved outside the insulating space body, and a vacuum sealing opening of the cathode vacuum cover plate is nested in the end part of the negative high-voltage cathode feed channel; the cathode high-voltage wire and the anode electrode form a high-voltage electric field, so that a narrow and extended breakdown path is formed in a gap between the cathode high-voltage wire and the cathode vacuum cover plate, and the phenomenon of gas breakdown between the cathode high-voltage wire and the cathode vacuum cover plate is avoided.

Description

Technical Field

[0001] This invention relates to the field of nanodose measurement technology, and in particular to a nanodose measurement device, system and method. Background Technology

[0002] Nanodosimetry is used to experimentally measure the nanoscale energy deposition during the interaction of ionizing radiation with equivalent human tissue by precisely measuring the number of ionization events of a single ion orbital within a defined nanovolume element, i.e., the size of the ionization cluster.

[0003] Nanodose detectors are used to traverse the nanoscale energy deposition of different radiating particles, obtaining the probability distribution characteristics of the number of ionized ions in the nanovolume (i.e., the probability density distribution of ionized cluster size). Currently, the structure of the FIRE (ion registration frequency) nanodose detector at the University of Zurich, Switzerland, is as follows: Figure 8 As shown (see Fabiano Vasi, Irina Kempf, Jürgen Besserer, Uwe Schneider. "FIRE: A compact nanodosimeter detector based onion amplification in gas", Nuclear Instruments and Methods in Physics Research, Section A 999 (2021) 165116), a low-resistivity glass wafer is directly bonded to the top of the microchannel of a dielectric substrate using an adhesive encapsulation method, and vacuum control of the microchannel is achieved through adhesive encapsulation. Although this technical solution avoids some technical defects: (1) the difficulty of introducing high voltage into the vacuum chamber, and (2) the problem of electrical breakdown caused by high voltage in a vacuum environment of about 1 Torr, the problem of vacuum sealing stability brought about by this technical solution is very prominent.

[0004] The nanodose detector operates as follows: The FIRE nanodose detector cavity is filled with a low-density tissue-equivalent gas (e.g., propane (C3H8)). A positive anode voltage is applied to the bottom of the cavity, and a dielectric plate with micropores is housed in the detector cover above the anode. The dielectric plate is 1 cm thick and extends from the signal readout end (z=0 cm) to the cathode (z=1 cm) located at its top. The cathode is made of low-resistance silicate glass, with a surface covered by carbon and copper ribbons, and a negative high voltage of -700 V to -2500 V is applied. An Am-241 source is placed at z=-1.1 cm, which emits a collimated alpha particle beam. The alpha particles are detected by the surface barrier detector after passing through the gas. As the alpha particles move toward the surface barrier detector, they ionize the working gas. When the nanodose detector detects an alpha particle, it opens a measurement window. The electric field generated by the anode and cathode voltages creates a funnel effect, causing ions to drift into the micropores of the dielectric plate. Within the microchannels of the dielectric substrate, ions are accelerated more strongly due to the high voltage at the cathode, generating new ion-electron pairs through collisional ionization. The negatively charged electrons accelerate away from the cathode, forming an electron avalanche, which is ultimately collected by the signal readout pads (z=0 cm) around the holes in the dielectric substrate.

[0005] Irina Kempf et al. improved the FIRE (ion registration frequency) nanodose detector from the University of Zurich, Switzerland (see Irina Kempf, Tamara Melina Hoffmann, Jürgen Besserer, Uwe Schneider. "Development and characterization of a compact nanodosimetric detector", Nuclear Instruments and Methods in Physics Research A 1075 (2025) 170337), and proposed a surface barrier detector. This detector adopts a circular design, which greatly accelerates the vacuum pumping speed, and can reach a pressure of less than 0.02 Torr in less than 30 minutes.

[0006] The gas pressure within the nanodose detector cavity directly determines the gas density, thus affecting the equivalent multiple of the sensitive volume and is one of the key measurement parameters. Therefore, the internal gas pressure must be kept highly stable, placing extremely high demands on the vacuum sealing performance of the structure. However, both the FIRE nanodose detector and the surface barrier detector technologies mentioned above involve directly bonding a low-resistivity glass wafer to the top of the microchannels of a high-resistivity dielectric substrate using adhesive bonding. This adhesive bonding method is limited by factors such as the material permeability of the adhesive itself, the difference in surface flatness between the dielectric substrate and the low-resistivity glass wafer, and the unavoidable air bubbles during the bonding process. This makes it difficult to maintain vacuum sealing performance over a long period of time, and thus fails to meet the requirements for precise nanodose measurement. Furthermore, when the high-resistivity dielectric substrate is made of hard and brittle ceramic material, the vacuum connection and mechanical fit between it and the cavity become more complex, further exacerbating the difficulty of vacuum control.

[0007] Therefore, in view of the above-mentioned technical defects, the present invention improves the negative electrode vacuum cover plate in the nanodose detector structure. It uses metal materials to encapsulate the high voltage protection components, micropore structure and high voltage insulation components in the cavity. The integrated structure achieves stable maintenance of cavity vacuum, fundamentally solving the problems of difficult vacuum control and low sealing reliability in the prior art.

[0008] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the applicant studied a large number of documents and patents when making this invention, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that the present invention does not possess the features of these prior art. On the contrary, the present invention already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0009] In existing technologies, nanodose detectors can perform ergonomic measurements of the energy deposition of different radiation particles at the nanoscale, thereby obtaining the probability distribution characteristics of the number of ionized ions within a nanovolume, i.e., the probability density distribution of the ionization cluster size. Currently, the FIRE (ion registration frequency) nanodose detector developed by the University of Zurich in Switzerland has the following structure... Figure 8As shown (for related details, please refer to: Fabiano Vasi, Irina Kempf, Jürgen Besserer, Uwe Schneider. "FIRE: A compact nanodosimeter detector based on ion amplification in gas", Nuclear Instruments and Methods in Physics Research, Section A 999(2021) 165116). The technical solution adopted by this nanodosimeter detector is as follows: a low-resistivity glass wafer is directly bonded to the top of the microchannel of the dielectric substrate through adhesive seams, and the vacuum degree of the microchannel is controlled by adhesive sealing.

[0010] However, it should be noted that the aforementioned FIRE nanodose detector uses an adhesive bonding process to directly attach a low-resistivity glass wafer to the top of the microchannels of a high-resistivity dielectric substrate. This adhesive bonding process has several inherent limitations, including the permeability of the adhesive itself, differences in surface flatness between the dielectric substrate and the low-resistivity glass wafer, and the inability to completely avoid air bubble formation during the bonding process. These factors combined make it difficult to maintain stable vacuum sealing performance over the long term, which is clearly unsuitable for the stringent accuracy requirements of nanodose measurement. Furthermore, if the dielectric substrate is made of a hard and brittle ceramic material, the difficulty of vacuum sealing and mechanical assembly between it and the cavity will further increase, significantly enhancing the overall complexity of vacuum control.

[0011] To address the shortcomings of existing technologies, this invention provides a nanodose measurement device, comprising a main frame and an electric field insulation protection structure. The electric field insulation protection structure includes a negative electrode vacuum cover plate, a high-voltage protection component, and a high-voltage insulation component mounted on the main frame. A cavity is centrally located within the high-voltage protection component, and a high-resistivity dielectric plate is disposed on the outer bottom of the cavity. The high-voltage insulation component has a through-hole negative high-voltage cathode feed channel, such that the unpenetrated portion of the high-voltage insulation component forms a barrier. The edges of the high-voltage protection component and the high-voltage insulation component are nested together, thereby forming a barrier between the high-voltage protection component and the barrier. An insulating space is constructed to enclose the negative high-voltage cathode feed channel. A negative electrode vacuum cover is fitted over the insulating space, and the vacuum seal of the negative electrode vacuum cover is nested at the end of the negative high-voltage cathode feed channel. The negative electrode vacuum cover is mounted on the main frame. An anode is located inside the main frame. When the negative electrode vacuum cover is in a vacuum environment, the cathode high-voltage line, which runs through the negative high-voltage cathode feed channel and is connected to the cathode, forms a high-voltage electric field with the anode. This creates a narrow and extended breakdown path between the cathode high-voltage line and the negative electrode vacuum cover, preventing gas breakdown between them. By adjusting the load voltage of the cathode high-voltage line and the anode within the negative high-voltage cathode feed channel using the control unit in the controlled dose measurement device, a funnel-shaped electric field can be established between the grounding electrode and the anode. This funnel-shaped electric field radiates outward from the anode and converges at the entrance of the microchannel, thereby driving ionized ions generated by the ionization of primary particles to drift along the direction of the electric field and ultimately enter the microchannel, achieving effective collection of ionized ions. Simultaneously, a localized high-intensity electric field is formed within the microchannel between the cathode high-voltage line and the grounding electrode. Ionized ions entering the microchannel undergo avalanche ionization under the influence of this localized strong electric field, generating a large number of avalanche electrons. The generated electron signal is captured by a readout electrode disposed on a high-resistivity dielectric plate, thereby realizing the counting of nanodosimetric ionized ions.

[0012] In this invention, a high-voltage protection component and a high-voltage insulation component are nested to construct an insulating space, replacing the traditional adhesive sealing process. This structurally avoids inherent problems such as adhesive permeability, bonding bubbles, and surface flatness differences, significantly improving the long-term stability of the vacuum seal and precisely matching the stringent accuracy requirements of nanodoscopy. The invention optimizes the overall assembly structure design. Through component edge nesting and the adaptive installation of the negative electrode vacuum cover and the insulating space, the difficulty of vacuum sealing connection and mechanical assembly between the high-resistivity dielectric plate and the cavity is reduced, significantly decreasing the complexity of vacuum control. Furthermore, the high-resistivity nested structure forms a narrow, extended breakdown path, preventing gas breakdown between the cathode and negative electrode vacuum cover, ensuring a stable high-voltage electric field, and ensuring that ionized ions pass smoothly through the microchannels and are accurately captured by the readout electrode, thus improving measurement reliability.

[0013] According to a preferred embodiment, the edge of the high-voltage protection component for contacting the high-voltage insulation component is provided with a first nesting groove; the edge of the high-voltage insulation component is provided with a second nesting groove; the high-voltage protection component and the high-voltage insulation component are interlocked with each other through the opposing first and second nesting grooves, wherein the cavity accommodates at least a portion of the blocking part, and the position of the microchannel is arranged opposite to the radial section of the negative high-voltage cathode feed channel.

[0014] In the technical solution of this invention, the nested design enables a tight fit between the high-voltage protection component and the high-voltage insulation component, thereby constructing a complete insulating space that effectively isolates the high-voltage electric field from the external environment, preventing electric field leakage and unnecessary charge accumulation. Secondly, this structure optimizes the electric field distribution, creating a more uniform funnel-shaped electric field in the gap between the negative high-voltage cathode feed channel and the negative electrode vacuum cover, thus improving the migration efficiency of ionized ions and the stability of signal acquisition. Furthermore, the nested structure enhances the mechanical strength and sealing performance of the device, avoiding insufficient vacuum sealing caused by material permeability, surface flatness differences, and bubble formation in traditional sealing methods, thereby improving the reliability and long-term operational stability of the device under high-voltage environments. Through this structural design, ionized ions can be guided along a narrow and extended breakdown path to the microchannel, generating an avalanche ionization signal within the microchannel, ensuring the accuracy and repeatability of measurements. Simultaneously, the nested structure effectively suppresses local electric field concentration, reducing the risk of gas breakdown and ensuring the safe operation of the device in low-density gas environments.

[0015] In terms of volume design, the nested design eliminates the need for additional adhesive layers and redundant assembly space. Compared to the bonding connection of traditional adhesive sealing processes, it significantly reduces the assembly gaps and structural redundancy between components, achieving miniaturization of the device. Moreover, while ensuring sealing performance and structural stability, the nested design avoids the reserved bonding space required for adhesive sealing, allowing high-voltage protection components and high-voltage insulation components to be compactly integrated. This is more suitable for the miniaturization and lightweight application requirements of nanodosage measurement devices, broadening the application range of the device in space-constrained scenarios.

[0016] According to a preferred embodiment, the negative high-voltage cathode feed channel is disposed in the center of the high-voltage insulation component and protrudes from one end of the high-voltage insulation component; the shape and size of the vacuum sealing port of the negative electrode vacuum cover plate are adapted to the protruding part of the negative high-voltage cathode feed channel.

[0017] This design effectively reduces the gap between the negative high-voltage cathode feed channel and the negative electrode vacuum cover, especially the distance in the top region, thus forming a narrow and extended breakdown path. This optimized path helps improve the uniformity of the electric field distribution, allowing ionized ions to migrate more efficiently into the microchannels under the influence of the high-voltage electric field, thereby improving signal collection efficiency. Simultaneously, the tight fit between the vacuum seal and the protruding portion of the negative high-voltage cathode feed channel enhances the vacuum sealing of the entire device, preventing gas leakage or electric field interference caused by structural mismatch, thus ensuring the stability and accuracy of the measurement. Furthermore, this structural design improves the mechanical assembly precision of the device, making the connections between components more reliable and contributing to the overall system integration and reliability.

[0018] According to a preferred embodiment, the negative high-voltage cathode feed channel is in the shape of a straight channel, and the microchannel in the center of the high-resistivity dielectric plate is approximately coincident with the axial centerline of the negative high-voltage cathode feed channel; when a funnel-shaped electric field is formed between the cathode and the anode, ionized ions generated by the ionized gas drift toward the high-voltage protection component and enter the microchannel.

[0019] This technology optimizes the matching between the electric field and the ion migration path. This structure ensures that ionized ions can drift stably along the axial direction into the microchannels under the influence of the funnel-shaped electric field, improving ion collection efficiency. Simultaneously, axial alignment reduces electric field distortion, resulting in a more uniform electric field distribution, thereby enhancing the acceleration and collisional ionization capabilities of ionized ions within the microchannels and improving the generation efficiency of avalanche ionization signals. Furthermore, this design contributes to improved device compactness, facilitating manufacturing and assembly, while also enhancing signal readout stability, providing a more accurate physical basis for nanodoscopy measurements.

[0020] According to a preferred embodiment, the high-voltage protection component is made of a high-resistance material, including epoxy resin, ceramic, polymer insulating material and sapphire crystal material; the bottom diameter of the high-voltage protection component ranges from 50mm to 200mm, so that ionized ions can be effectively captured and collected by the micropores.

[0021] This technology significantly enhances the isolation capability against high-voltage electric fields by using high-resistivity materials to fabricate the high-voltage protection components, effectively suppressing leakage current, reducing the risk of gas breakdown, and ensuring the stability of the electric field distribution. Simultaneously, the bottom diameter, set within the range of 50mm to 200mm, helps to form a wider ion collection area, improving ion migration efficiency and signal capture capability. This size design ensures electric field uniformity while avoiding electric field concentration due to excessive size or structural redundancy due to excessive size, thereby optimizing the device's sensitivity and reliability and providing a more stable physical environment and higher measurement accuracy for nanodoscopy.

[0022] According to a preferred embodiment, the pore size of the microchannel ranges from 0.5 mm to 10 mm, and the depth of the microchannel ranges from 3 mm to 30 mm, so that ionized ions entering the microchannel generate avalanche ionization signals in the microchannel.

[0023] This technology optimizes the movement path and electric field range of ionized ions within the micropores. The appropriate pore size and depth effectively control the drift velocity and collision frequency of ionized ions, enabling the generation of stable avalanche ionization signals within the micropores and improving signal strength and detectability. Simultaneously, this size range balances the permeability of the micropores with the electric field enhancement effect, avoiding situations where ions cannot easily enter due to excessively small pore size or where signal attenuation occurs due to excessive depth. This design ensures effective collection of ionized ions while improving the device's sensitivity and measurement accuracy for low-dose particles, providing a reliable foundation for signal generation and readout in nanodosimetry research.

[0024] According to a preferred embodiment, the high-voltage insulation component is made of a high-resistivity material, including epoxy resin, ceramic, polymer insulating material, and sapphire crystal material; the distance between the bottom end face of the barrier portion and the cathode in the high-voltage insulation component ranges from 0.5mm to 5mm; the depth of the first nested groove in the high-voltage protection component ranges from 5mm to 20mm; and the depth of the second nested groove in the high-voltage insulation component ranges from 5mm to 20mm.

[0025] This technology significantly enhances the isolation capability of high-voltage electric fields by using high-resistivity materials to fabricate the high-voltage insulation components, effectively suppressing leakage current, reducing the risk of gas breakdown, and ensuring the stability of the electric field distribution. The distance between the bottom end face of the barrier and the cathode is controlled within the range of 0.5mm to 5mm, which helps to form a uniform and stable electric field distribution, avoiding breakdown caused by localized electric field concentration. Simultaneously, the depth of the nested groove is set to 5mm to 20mm, ensuring a tight nested structure between the high-voltage protection component and the high-voltage insulation component, enhancing the sealing and mechanical stability of the insulation space, thereby improving the device's vacuum holding capability and electric field control accuracy, and providing a safer and more reliable electric field environment and structural foundation for nanodose measurement.

[0026] The present invention provides a nanodose measurement method from a second aspect. The method includes: nesting the edge portions of a high-voltage protection component and a high-voltage insulation component with each other, thereby constructing an insulating space covering a negative high-voltage cathode feed channel by the high-voltage protection component and the barrier portion; wherein, a cavity is provided in the center of the high-voltage protection component, and a high-resistivity dielectric plate is provided on the outer side of the bottom of the cavity; the high-voltage insulation component is provided with a negative high-voltage cathode feed channel penetrating itself, such that the unpenetrated portion of the high-voltage insulation component forms a barrier portion; a negative electrode vacuum cover is fitted over the outside of the insulating space, and the vacuum seal of the negative electrode vacuum cover is nested at the end of the negative high-voltage cathode feed channel; the negative electrode vacuum cover is then fitted over the edge of the insulating space. An empty cover plate is installed on the main frame; an anode is installed inside the main frame; when the negative electrode vacuum cover plate is in a vacuum environment, the cathode high-voltage line that runs through the negative high-voltage cathode feed channel and is connected to the cathode forms a high-voltage electric field with the anode, making the gap between the cathode high-voltage line in the negative high-voltage cathode feed channel and the negative electrode vacuum cover plate form a narrow and extended breakdown path, avoiding gas breakdown between the cathode high-voltage line and the negative electrode vacuum cover plate. Thus, when the radiation source delivers primary particles to the high-voltage electric field through the beam collimator, the ionized ions pass through the micro-channels on the high-resistivity dielectric plate, are captured by the readout electrode on the high-resistivity dielectric plate, and are counted using nanodosimetric ionization.

[0027] The method of this invention constructs an insulating space covering the negative high-voltage cathode feed channel by nesting the edge portions of a high-voltage protection component and a high-voltage insulation component. This effectively isolates the high-voltage electric field from the external environment, preventing gas breakdown. This nested structure ensures a tight fit between the components, improving vacuum sealing and structural stability. While maintaining electric field uniformity and insulation performance, this method optimizes the device's structural design, improves the accuracy and safety of nanodose measurement, and provides a reliable technical path for achieving stable and efficient ionization ion counting.

[0028] According to a preferred embodiment, in this method, the edge of the high-voltage protection component for contacting the high-voltage insulation component is provided with a first nesting groove; the edge of the high-voltage insulation component is provided with a second nesting groove; the high-voltage protection component and the high-voltage insulation component are interlocked with each other through the opposing first and second nesting grooves, wherein the cavity accommodates at least a portion of the blocking part, and the position of the microchannel is arranged opposite to the radial section of the negative high-voltage cathode feed channel.

[0029] This method achieves a tight fit and stable fixation in structure by setting a first nested groove and a second nested groove on the edges of the high-voltage protection component and the high-voltage insulation component, respectively, and connecting the two by interlocking them. This effectively improves the vacuum sealing performance and electric field distribution uniformity of the device.

[0030] This invention provides a nanodose measurement system from a third aspect. The system includes: a vacuum control system for extracting air from the nanodose measurement device and creating a vacuum environment within the device; a nanodose measurement device for capturing particles and counting nanodose-induced ionized ions; and a data acquisition and analysis system for correlating each primary particle with its associated ionized ion and recording the arrival time of each ionized ion relative to a trigger. The nanodose measurement device includes a main frame and an electric field insulation protection structure. The electric field insulation protection structure includes a negative electrode vacuum cover plate, a high-voltage protection component, and a high-voltage insulation component mounted on the main frame. The high-voltage protection component has a central cavity, and a high-resistivity dielectric plate is mounted on the outer bottom of the cavity. The high-voltage insulation component has a through-hole negative high-voltage cathode feed channel, such that the non-penetrated portion of the high-voltage insulation component forms a barrier. The edges of the high-voltage protection component and the high-voltage insulation component... The components are nested together, forming an insulating space that encloses the negative high-voltage cathode feed channel. The negative electrode vacuum cover is fitted over the insulating space, and its vacuum seal is nested at the end of the negative high-voltage cathode feed channel. The negative electrode vacuum cover is mounted on the main frame. An anode is located inside the main frame. When the negative electrode vacuum cover is in a vacuum environment, the cathode high-voltage line that runs through the negative high-voltage cathode feed channel and connects to the cathode forms a high-voltage electric field with the anode. This creates a narrow and extended breakdown path between the cathode high-voltage line and the negative electrode vacuum cover, preventing gas breakdown between them. Thus, when the radiation source delivers primary particles to the high-voltage electric field through the beam collimator, ionized ions pass through the micropores on the high-resistivity dielectric plate, are captured by the readout electrode on the high-resistivity dielectric plate, and are counted using nanodosimetry.

[0031] The nanodose measurement system of this invention achieves precise control of the vacuum environment and efficient capture and analysis of ionized ions by integrating a vacuum control system, a nanodose measurement device, and a data acquisition and analysis system. The vacuum control system ensures a stable low-pressure environment within the device, providing the necessary physical conditions for the ionization process. The data acquisition and analysis system improves measurement accuracy and data reliability through time correlation and signal processing. The electric field insulation protection structure adopts a nested design, effectively preventing gas breakdown and ensuring the stability and insulation performance of the high-voltage electric field, thereby improving the long-term operational reliability of the device. The system has a compact overall structure and integrated functions, significantly improving the stability, accuracy, and automation level of nanodose measurement, providing a scientifically sound solution for high-precision, high-reliability radiation dose measurement. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the nanodose measurement device provided by the present invention; Figure 2This is a cross-sectional structural schematic diagram of the nanodose measurement device provided by the present invention; Figure 3 This is a schematic diagram of the nanodose measurement device provided by the present invention; Figure 4 This is a schematic diagram of the bottom outer side of the high-voltage protection component provided by the present invention; Figure 5 This is a schematic diagram of the non-bottom structure of the high-voltage protection component provided by the present invention; Figure 6 This is a schematic diagram of the top structure of the high-voltage insulation assembly provided by the present invention; Figure 7 This is a schematic diagram of the bottom structure of the high-voltage insulation component provided by the present invention; Figure 8 This is a schematic diagram of a prior art nanodose measurement device; Figure 9 This is a comparative schematic diagram of the measurement results provided by the present invention; Figure 10 This is a schematic diagram of the composition of the nanodose measurement system provided by the present invention.

[0033] List of reference numerals 100: Nanodose measurement device; 110: Negative electrode vacuum cover plate; 111: Vacuum sealing port; 112: Cover plate body; 113: Fixing part; 120: High voltage protection component; 121: Microchannel; 122: Readout electrode; 123: Grounding electrode; 124: High resistance dielectric plate; 125: Cavity; 126: First nested groove; 127: Bottom; 128: Micropore; 129: Stepped structure; 130: High voltage insulation component; 131: Cathode inlet; 132: Barrier part; 133: Second nested groove; 134: Negative high voltage cathode feed channel; 135: Texture; 140: Main frame; 141: Anode; 142: Cathode; 143: Charged particle; 144: Primary particle detector; 150: Vacuum control system; 160: Data acquisition and analysis system. Detailed Implementation

[0034] The following is a detailed explanation with reference to the accompanying drawings.

[0035] Existing nanodose measurement devices, also known as nanodose detectors, are used to measure the nanoscale energy deposition of different radiating particles, obtaining the probability distribution characteristics of the number of ionized ions in the nanovolume (i.e., the probability density distribution of ionized cluster size). Currently, the FIRE (ion registration frequency) nanodose detector at the University of Zurich, Switzerland, has the following structure: Figure 8As shown (see Fabiano Vasi, Irina Kempf, Jürgen Besserer, Uwe Schneider. "FIRE: A compact nanodosimeter detector based on ion amplification in gas", Nuclear Instruments and Methods in Physics Research, Section A 999 (2021) 165116), a low-resistivity glass wafer is directly bonded to the top of the microchannel of a dielectric substrate by adhesive encapsulation, and vacuum control of the microchannel is achieved by adhesive encapsulation. Figure 8 The ion signal output position, cathode voltage and anode voltage input positions, trigger signal output position, gas inflow output position, gas outflow output position, and pressure gauge are also shown.

[0036] This invention also tested the aforementioned nanodose detector. During the operation of the nanodose detector, the high-voltage electric field distribution across the sensitive volume is crucial for driving ionized ions into the micropores and inducing ionization avalanche to generate a readout signal. This invention uses a resistivity of approximately 10... 10 A low-resistance silicate glass with a resistance of Ω·cm is placed on top of a dielectric plate (similar to the high-resistance dielectric plate of this invention). Copper electrodes are covered on the glass, serving as the cathode of the nanodose detector unit. The cathode is connected to a negative high voltage via a high-voltage power supply. The bottom side of the dielectric plate is covered with copper, and the copper electrode portion surrounding the hole serves as the readout electrode. The remaining area around the readout electrode is also covered with copper and grounded to ensure a regular funnel-shaped electric field distribution. To meet the precise control of the gas pressure within the airtight chamber of the nanodose detector, this invention seals the dielectric plate in a small cavity communicating with the airtight chamber. However, experimental results show that when the gas pressure inside the cavity is within the required measurement range of 1 Torr to 10 Torr, the high voltage easily breaks down the low-density gas, causing measurement errors or even damaging the equipment.

[0037] Furthermore, the aforementioned FIRE nanodose detector directly bonds a low-resistivity glass wafer to the top of the microchannels of the dielectric substrate using an adhesive bonding method. This bonding method is limited by factors such as the material permeability of the adhesive itself, the difference in surface flatness between the dielectric substrate and the low-resistivity glass wafer, and the unavoidable air bubbles during the bonding process. This makes it difficult to maintain vacuum sealing performance over a long period of time, and thus fails to meet the requirements for precise nanodose measurement. In addition, when the dielectric substrate is made of a hard and brittle ceramic material (mainly composed of zirconium oxide (ZrO2) and up to 4% yttrium oxide (Y2O3)), the vacuum connection and mechanical fit between it and the cavity become more complex, further exacerbating the difficulty of vacuum control.

[0038] To address the aforementioned deficiencies, this invention provides a nanodose measurement device, system, and method. This invention can also provide an electric field insulation protection structure for a nanodose detector, comprising a negative electrode vacuum cover 110, a high-voltage protection component 120, and a high-voltage insulation component 130. This invention can also protect the high-voltage protection component 120. This invention can also protect the high-voltage insulation component 130. This invention can also protect the negative electrode vacuum cover 110.

[0039] Specifically, this invention improves the structure of the aforementioned low-resistivity glass wafer by designing a negative electrode vacuum cover plate 110, a high-voltage protection component 120, and a high-voltage insulation component 130. The high-voltage protection component 120 and the high-voltage insulation component 130 are nested at their edges, thereby forming an insulating space covering the negative high-voltage cathode feed channel 134. The negative electrode vacuum cover plate 110 is also fitted over the insulating space, and its vacuum seal 111 is nested at the end of the negative high-voltage cathode feed channel 134. This end protrudes from the main body and serves as the cathode inlet 131. The cathode 142 is connected to a highly conductive wire, i.e., a cathode high-voltage line. The cathode vacuum KF flange high-voltage electrode is connected to an external high-voltage power supply to apply a negative high voltage (around -2000V) to the cathode 142. The cathode high-voltage line passes through the negative high-voltage cathode feed channel 134 and is opposite to or in contact with the micro-hole 128 in the center of the high-voltage protection component 120. With this design, when the negative electrode vacuum cover plate 110 is in a vacuum environment, the cathode high-voltage line that runs through the negative high-voltage cathode feed channel 134 and is connected to the cathode 142 forms a high-voltage electric field with the anode 141. This causes the gap between the cathode high-voltage line in the negative high-voltage cathode feed channel 134 and the negative electrode vacuum cover plate 110 to form a narrow and extended breakdown path, thus avoiding gas breakdown between the cathode high-voltage line and the negative electrode vacuum cover plate 110.

[0040] The measurement principle of the nanodose measuring device 100 of the present invention is as follows: like Figure 2As shown, the high-voltage protection component 120 and the high-voltage insulation component 130 form an insulating space. The insulating space is sealed to a vacuum chamber. A micropore 128 with a diameter of 0.5 mm to 3 mm is prepared at the center of the high-voltage protection component 120. The micropore 128 communicates with the microchannel 121 on the high-resistivity dielectric plate 124, forming an ionization ion collection channel. One end of the ionization ion collection channel of the high-voltage protection component 120 is connected to the readout electrode 122 and the grounding electrode 123, and is in contact with the low-density equivalent gas inside the vacuum chamber. A negative high-voltage line connected to the cathode 142 is loaded with a negative high voltage. After being ejected, charged particles 143 pass through the low-density equivalent gas (such as propane), ionizing the propane gas and decomposing it to generate ionized ions and ionized electrons. Under the action of the electric field, the positive ionized ions drift along the field lines towards the micropore 128 of the high-voltage protection component 120 and are collected into the microchannel 121. A localized high-intensity electric field is formed inside the microchannel 121 between the cathode 142 and the ground electrode 123. Ionized ions entering the microchannel 121 undergo avalanche ionization under the influence of this localized strong electric field, generating a large number of avalanche electrons. The generated electron signal is captured by the readout electrode 122 disposed on the high-resistivity dielectric plate 124, thereby realizing the counting of nanodosimetric ionized ions.

[0041] Example 1 This embodiment provides a nanodose measuring device 100.

[0042] The nanodose measuring device 100 includes a main frame 140 and an electric field insulation protection structure. For example... Figure 1 and Figure 2 As shown, the electric field insulation protection structure includes a negative electrode vacuum cover plate 110, a high-voltage protection component 120, and a high-voltage insulation component 130 disposed on the main frame 140. Preferably, Figure 1 and Figure 2 The illustration shows a preferred embodiment of the present invention, in which the radial cross-section of the negative electrode vacuum cover 110, the high-voltage protection component 120, and the high-voltage insulation component 130 is circular. In actual product design, the radial cross-section of the negative electrode vacuum cover 110, the high-voltage protection component 120, and the high-voltage insulation component 130 is not limited to a circle, but can also be a polygon, a square, or other structures.

[0043] Preferably, the negative electrode vacuum cover 110 is made of metal, preferably a rust-resistant metal material, and more preferably, the negative electrode vacuum cover 110 is made of stainless steel. Stainless steel is chosen because its strength and resistance to deformation protect the internal electric field insulation structure from deformation. More preferably, such as... Figure 1 and Figure 2As shown, the negative electrode vacuum cover 110 includes a vacuum sealing port 111, a cover body 112, and a fixing part 113. Preferably, the cover body 112 is cap-shaped with a cavity. The vacuum sealing port 111 is located at the top of the cover body 112, and its diameter is significantly smaller than that of the cover body 112. The vacuum sealing port 111 is used to seal and fix with the vacuum KF interface of the vacuum KF flange high-voltage electrode. The bottom of the cover body 112 is provided with an outwardly flared edge, which is the fixing part 113. The fixing part 113 is provided with several holes for installation. These holes are used to pass bolts to install the negative electrode vacuum cover 110 onto the main frame 140. Preferably, when the negative electrode vacuum cover plate 110 is installed on the main frame 140, a sealing ring can also be provided between its fixing part 113 and the main frame 140 to seal the gap between the negative electrode vacuum cover plate 110 and the main frame 140, so that the vacuum control system 150 can easily form a vacuum environment inside the negative electrode vacuum cover plate 110 by evacuating air.

[0044] Preferably, the fixing method between the negative electrode vacuum cover plate 110 and the main frame 140 is not limited to bolt connection, but can also be welding connection, riveting connection, snap-on quick connection, threaded connection, magnetic auxiliary fixing and sealing compression, etc.

[0045] The inventors discovered that, for dielectric substrate materials such as epoxy resin and zirconium dioxide ceramic used in existing technologies, after several measurements, ionized ions and / or ionized electrons accumulate at the outlet and sidewalls of the microchannels 121 of the high-resistivity dielectric substrate 124, forming a reverse electric field in the microchannels 121. This significantly affects the collection efficiency of ionized ions, leading to a decrease in the performance of the nanodose detector. Therefore, this invention improves the materials used in the fabrication of the high-voltage protection component 120 and the high-voltage insulation component 130.

[0046] Preferably, the high-voltage protection component 120 is one of the core components for realizing the measurement of key parameters of nanodose, and is the core foundation for realizing ion-driven and ion-ion signal acquisition. The high-voltage protection component 120 is made of high-resistivity materials, including epoxy resin, ceramics, polymer insulating materials, and sapphire crystal materials.

[0047] The high-resistivity dielectric plate 124 on the outer side of the bottom 127 of the high-voltage protection component 120 is made of a high-resistivity material, including epoxy resin, ceramic, polymer insulating material and sapphire crystal material.

[0048] Preferably, the high-voltage insulation component 130 is made of a high-resistance material, including epoxy resin, ceramic, polymer insulating material and sapphire crystal material.

[0049] As shown above, this invention uses high-resistivity materials to fabricate the high-voltage protection component 120, the high-resistivity dielectric plate 124, and the high-voltage insulation component 130. The improved high-resistivity material offers significant advantages in isolating high-voltage electric fields, specifically addressing the pain points of existing technologies and meeting the core operational requirements of the nanodose measurement device 100. Compared to existing low-resistivity materials (such as low-resistivity glass wafers), the high-resistivity material, due to its significantly higher resistivity, can effectively suppress leakage current under high voltage. In low-density gas environments of 1 Torr to 10 Torr, it can significantly reduce the risk of high-voltage breakdown, avoid electric field disturbances, measurement errors, and equipment damage, ensure reliable isolation between the high-voltage electric field and the external environment, and maintain the stability of the electric field distribution. Meanwhile, in response to the problem that traditional epoxy resin, zirconium dioxide ceramic and other materials tend to accumulate ionized ions or electrons at the outlet and sidewall of the micropore 121 after long-term use, which in turn forms a reverse electric field that interferes with the collection of ionized ions, the high resistivity of high-resistivity materials can slow down the rate of charge migration and accumulation, reduce the generation of reverse electric fields, ensure that the positive electric field distribution driving ionized ions is not disrupted, and maintain the effectiveness of electric field isolation.

[0050] Preferably, the end face diameter of the high-resistivity dielectric plate 124, the diameter of the cathode 142, and the diameter of the anode 141 are consistent, and the diameter φ ranges from 50mm to 200mm. Exceeding this range can easily lead to uneven electric field, affecting the effective capture and collection of ionized ion signals. This configuration offers several key advantages: (1) The precise matching of the three dimensions can construct a coaxial symmetrical structure, ensuring the formation of a uniform funnel-shaped electric field within the sensitive volume, avoiding electric field distortion caused by size mismatch, and ensuring the stability of the migration path of ionized ions; (2) The size range of 50mm~200mm can effectively suppress the electrode edge effect, avoid the risk of gas breakdown caused by excessive concentration of local electric field, and balance the electric field strength and processing accuracy to prevent equipment instability caused by too small or too large size. (3) A uniform electric field can improve the collection efficiency of ionized ions, reduce signal drift and dispersion, ensure the accuracy and repeatability of nanodose measurement, and meet the needs of precise capture of low ionization events.

[0051] The nanodose measurement device 100 relies on a "regular funnel electric field distribution" to ensure ion collection efficiency. The matching of the high-voltage protection component 120 with the diameters of the cathode 142 and the anode 141 is crucial for the uniformity of the electric field. The high-resistivity material has stable insulation properties and can work synergistically with this size characteristic to avoid electric field distortion caused by uneven insulation of the material. At the same time, reliable isolation ensures that the high-voltage electric field only acts on the sensitive volume, further improving the accuracy of ion driving and signal acquisition, and providing core support for the performance optimization of the nanodose measurement device 100.

[0052] Preferably, the present invention uses COMSOL Multiphysics to calculate the electrostatic field. When only the voltage is applied to the anode 141 and the voltage of the cathode 142 is set to ground, the field strength in the vacuum chamber is uniformly distributed, which is not conducive to the collection and counting of ionized ions.

[0053] like Figure 3 As shown, the electric field at the inlet of the microchannel 121 exhibits a distinct funnel distribution, and ionized ions will efficiently drift into the microchannel 121 under the drive of the electric field. Therefore, the end face diameter of the high-resistivity dielectric plate 124, the diameter of the cathode 142, and the diameter of the anode 141 are kept consistent and set within the size range defined by this invention, which helps ionized ions to drift efficiently into the microchannel 121. Figure 3 As shown, the vacuum chamber is in a vacuum environment, meaning the interior is filled with a low-density gas (10). -6 g / cm 3 Charged particles 143 are emitted from the radiation source, pass through a high-voltage electric field, and are ionized into ionized ions. A primary particle detector 144 is located at one end of the vacuum chamber of the main frame 140, opposite the radiation source. Figure 3 As shown, ionized ions are captured and detected by primary particle detector 144.

[0054] like Figure 5 As shown, a cavity 125 is provided in the center of the high-voltage protection component 120. (As indicated...) Figure 2 and 5 As shown, the cavity 125 is a concave structure with a central cutout. During installation, the side of the high-voltage protection assembly 120 with the concave structure faces upwards. Preferably, as shown... Figure 5 As shown, at least one through-hole 128 is provided on the inner side of the bottom 127 of the cavity 125. Figure 4 As shown, a high-resistivity dielectric plate 124 is provided on the outer side of the bottom 127 of the cavity 125.

[0055] like Figure 4 As shown, the bottom 127 of the cavity 125 and the wall of the high-voltage protection assembly 120 form a stepped structure 129. When the high-voltage protection assembly 120 is installed on the main frame 140, as... Figure 2 As shown, the stepped structure 129 allows the bottom 127 of the cavity 125 to hold the high-voltage protection component 120 in place at the edge of the vacuum chamber, preventing the high-voltage protection component 120 from shaking or shifting. This is especially important when installing the external negative vacuum cover 110, preventing displacement caused by contact with the high-voltage protection component 120 during installation.

[0056] like Figure 4 As shown, the high-resistivity dielectric plate 124 is provided with microchannels 121, readout electrodes 122 and grounding electrodes 123. Figure 4In this design, the elongated copper sheet serves as the readout electrode 122. The readout electrode 122 has a hole, which is the microchannel 121. The remaining portion of the high-resistivity dielectric substrate 124, excluding the readout electrode 122, serves as the ground electrode 123. For example, the ground electrode 123 is a copper sheet. Preferably, a gap exists between the ground electrode 123 and the readout electrode 122. The ground electrode 123 and the readout electrode 122 are non-conductive.

[0057] Microchannel 121 is located at the center of the high-resistivity dielectric plate 124, allowing ionized ions to pass through and generate avalanche ionization. Readout electrode 122 is located near microchannel 121. Readout electrode 122 is used to capture ionized ions and perform nanodoscopy ionization ion counting. Ground electrode 123 is also located near microchannel 121 and away from readout electrode 122. Ground electrode 123 is grounded to provide high-voltage protection. Preferably, the micropore 128 at the bottom 127 of cavity 125 communicates with the microchannel 121 on the high-resistivity dielectric plate 124, forming a complete channel for the entry and exit of ionized ions.

[0058] The high-voltage insulation component 130 is used to form a barrier between the cathode high-voltage line and the negative electrode vacuum cover 110, thereby preventing high-voltage breakdown between the cathode high-voltage line and the negative electrode vacuum cover 110. Figure 2 and Figure 7 As shown, the high-voltage insulation component 130 is provided with a negative high-voltage cathode feed channel 134 that penetrates through it, so that the non-penetrated portion of the high-voltage insulation component 130 forms a barrier portion 132. Since the high-voltage insulation component 130 is made entirely of a material with high resistance characteristics, the barrier portion 132 is non-conductive, thus creating an insulating environment for the negative high-voltage cathode feed channel 134 where the cathode high-voltage line is located.

[0059] Preferably, such as Figure 6 and Figure 7 As shown, the negative high-voltage cathode feed channel 134 is in the shape of a straight channel. Preferably, the radial cross-section of the negative high-voltage cathode feed channel 134 is not limited to... Figure 6 and Figure 7 The circular channel shown can also be a polygonal, square, or other channel structure. This negative high-voltage cathode feed channel 134 is used to insert the cathode high-voltage line. Preferably, in the installed state, the non-protruding end of the negative high-voltage cathode feed channel 134 is in contact with the high-resistivity dielectric plate 124 of the high-voltage protection assembly 120, and the microchannels 121 on the high-resistivity dielectric plate 124 are opposite to the negative high-voltage cathode feed channel 134. More preferably, the position of the microchannels 121 is opposite to the radial cross-section of the negative high-voltage cathode feed channel 134, which allows ionized ions to quickly enter the microchannels 121 under the action of the high-voltage electric field.

[0060] Preferably, the microchannel 121 and the axial centerline of the negative high-voltage cathode feed channel 134 are approximately coincident. Preferably, the microchannel 121 and the axial centerline of the negative high-voltage cathode feed channel 134 can be directly coincident, or their angle can be small (e.g., less than 5 degrees) leading to approximate coincidence. When a funnel-shaped electric field is formed between the cathode 142 and the anode 141, ionized ions generated by the ionized gas drift towards the high-voltage protection component 120 and enter the microchannel 121.

[0061] According to a preferred embodiment, the pore size of the micropore 121 ranges from 0.5 mm to 10 mm. Preferred values ​​for the pore size of the micropore 121 are 0.5 mm, 0.75 mm, 1 mm, 1.5 mm, 1.75 mm, 2 mm, 2.25 mm, 2.5 mm, 2.75 mm, 3 mm, 4 mm, 5 mm, 6 mm, 8 mm, 9 mm, and 10 mm. More preferably, the pore size of the micropore 121 ranges from 0.5 mm to 5 mm. The depth of the micropore 121 ranges from 3 mm to 30 mm, such that ionized ions entering the micropore 121 generate an avalanche ionization signal within the micropore 121. Preferred values ​​for the depth of the micropore 121 are 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, and 30 mm.

[0062] This invention also tested the electric field distribution under two conditions: a constant cathode voltage of -1500V and a microchannel radius of 0.5mm, with the anode 141 subjected to 10V and 30V respectively. Furthermore, this invention also tested the electric field distribution under two conditions: a constant cathode voltage of -1500V and a microchannel radius of 1mm, with the anode 141 subjected to 10V and 30V respectively.

[0063] The results of the two tests show that when the cathode and anode voltages are constant, the larger the radius of the micropores 121 in the high-resistivity dielectric plate 124 of the nanodose measuring device 100, the more pronounced the funnel effect. This characteristic exhibits the same trend under anode voltages of 10V and 30V.

[0064] The microchannel 121 in the center of the high-resistivity dielectric plate 124 is the core structure for collecting ionized ions. The pore size and depth of the microchannel 121 directly affect the sensitive volume of the nanodose measurement device 100 and whether ionized ions can generate an avalanche ionization signal within the microchannel 121. Figure 3As shown, when charged particles 143 are injected into the nanodosing device 100 and pass through the low-density tissue equivalent gas, the ionized gas generates electron-ion pairs. The ionized ions drift towards the high-resistivity dielectric plate 124 under the influence of the funnel electric field and are extracted into the microchannel 121. Subsequently, the ionized ions continue to accelerate under the field strength of the microchannel 121, gaining sufficient energy to collide and ionize with gas molecules. The resulting collisional ionized electrons are accelerated under the influence of the reverse electric field, further generating secondary and tertiary electrons, ultimately forming avalanche ionization. Finally, the avalanche electrons generate a sufficiently large pulse signal, which is captured by the readout electrode 122 as it leaves the hole, forming the required nanodosing ionization ion count. Therefore, the range of pore size and depth of the microchannel 121 is beneficial to ensuring that the ionized ions generate avalanche ionization within the microchannel 121.

[0065] like Figure 6 and Figure 7 As shown, the negative high-voltage cathode feed channel 134 is located in the center of the high-voltage insulation assembly 130 and protrudes from one end of the high-voltage insulation assembly 130. The protruding end of the high-voltage insulation assembly 130 serves as the cathode inlet 131. That is, the cathode inlet 131 and the negative high-voltage cathode feed channel 134 are integrally formed. This arrangement makes it easier to connect and seal the vacuum KF interface with the vacuum KF flange high-voltage electrode. Preferably, as... Figure 6 As shown, the top of the high-voltage insulation component 130 may also be provided with raised and recessed textures 135. Preferably, the outer surface of the high-voltage insulation component 130 may also be a smooth surface, and the textures 135 are a structure provided according to requirements, not a mandatory structure.

[0066] like Figure 2 As shown, the shape and size of the vacuum sealing port 111 of the negative electrode vacuum cover 110 are adapted to the protruding portion of the negative high-voltage cathode feed channel 134. This arrangement significantly reduces the distance between the negative electrode vacuum cover 110 and the high-voltage insulation assembly 130, especially the top distance, allowing them to be closer together. This structural optimization brings significant technical advantages.

[0067] First, by reducing the distance between the two, the electric field distribution can be effectively controlled, forming a narrow and extended breakdown path, thereby avoiding measurement errors or equipment damage caused by gas breakdown between the cathode high-voltage line and the negative electrode vacuum cover plate 110. Second, this tightly fitted structure enhances the uniformity of the electric field, helping to improve the collection efficiency of ionized ions and ensuring that ionized ions can stably migrate to the microchannel 121 and be effectively captured under the action of the high-voltage electric field. At the same time, this nested connection method also improves the vacuum sealing performance of the device, avoiding the sealing instability caused by material permeability, surface flatness differences, and bubble generation in traditional sealing methods. Existing technology uses low-resistivity glass wafers to seal the vacuum chamber. When performing nanodose measurements, the negative high voltage loading range is -500V to -2500V. However, when the gas pressure in the negative high voltage cathode feed channel 134 is near the working gas pressure (1 torr), the high voltage cathode high voltage line and the negative electrode vacuum cover plate 110 are very prone to breakdown, which will result in the inability to load the negative high voltage normally, or even damage the high voltage power supply and the internal parts of the nanodose detector.

[0068] Therefore, in this invention, the edge portions of the high-voltage protection component 120 and the high-voltage insulation component 130 are nested together, thereby forming an insulating space that covers the negative high-voltage cathode feed channel 134 with the high-voltage protection component 120 and the barrier portion 132. When the edge portions of the high-voltage protection component 120 and the high-voltage insulation component 130 form a nested structure, there is no direct breakdown path between the high-voltage cathode high-voltage line and the negative electrode vacuum cover plate 110.

[0069] Preferably, such as Figure 2 As shown, the edge of the high-voltage protection component 120 that contacts the high-voltage insulation component 130 is provided with a first nesting groove 126. Preferably, when the cross-section of the high-voltage protection component 120 is circular, the first nesting groove 126 is annular.

[0070] Preferably, the depth of the first nested groove 126 of the high-voltage protection component 120 ranges from 5mm to 20mm. Preferably, the preferred values ​​for the depth of the first nested groove 126 are 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 15mm, and 20mm.

[0071] like Figure 2 As shown, the edge of the high-voltage insulation component 130 is provided with a second nested groove 133. The depth of the second nested groove 133 in the high-voltage insulation component 130 ranges from 5mm to 20mm. Preferably, the preferred values ​​for the depth of the second nested groove 133 are 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 15mm, and 20mm.

[0072] like Figure 7As shown, when the cross-section of the high-voltage insulation component 130 is circular, the second nested groove 133 is annular. Preferably, the distance between the bottom end face of the barrier portion 132 in the high-voltage insulation component 130 and the cathode 142 ranges from 0.5mm to 5mm. The preferred distances between the bottom end face of the barrier portion 132 and the cathode 142 are 0.5mm, 1mm, 1.5mm, 2.5mm, 3.5mm, 4.5mm, and 5mm. This dimensional range ensures that the top of the barrier portion 132 is as close as possible to the inner top of the negative electrode vacuum cover plate 110, preventing breakdown through the edge gap between the high-voltage protection component 120 and the high-voltage insulation component 130.

[0073] like Figure 2 As shown, the high-voltage protection component 120 and the high-voltage insulation component 130 are interlocked with each other via opposing first nesting slots 126 and second nesting slots 133, wherein the cavity 125 accommodates at least a portion of the blocking portion 132. Figure 2 As shown, the first nested groove 126 of the high-voltage protection component 120 is embedded within the outer wall of the high-voltage insulation component 130. The second nested groove 133 of the high-voltage insulation component 130 is embedded within the wall of the cavity 125 of the high-voltage protection component 120. This structure transforms what could have been a short, straight gap into a narrow and extended tortuous path. According to Paschen's law, the gas breakdown voltage increases with the effective path length. The extended path significantly increases the voltage threshold required for breakdown, exceeding the actual high-voltage range of the nanodose measurement device 100 during operation. Simultaneously, the high-resistivity insulation material of the high-voltage insulation component 130 fully fills the gap to form a physical barrier, reducing leakage current. Furthermore, the nested structure limits electric field distortion, preventing local electric field concentration at the gap (electric field concentration reduces local breakdown voltage). The synergistic effect of both ensures the breakdown protection effect through path optimization and electric field suppression. Therefore, when the high-voltage protection component 120 and the high-voltage insulation component 130 are nested in this way, the gap between the cathode high-voltage line passing through the negative high-voltage cathode feed channel 134 and the negative electrode vacuum cover plate 110 forms a narrow and extended breakdown path, thus avoiding gas breakdown between the cathode high-voltage line and the negative electrode vacuum cover plate 110.

[0074] Preferably, since the depth of the cavity 125 can be greater than the depth of the first nested groove 126, the length of the barrier portion 132 needs to be adapted to the cavity 125. Therefore, the barrier portion 132 can protrude from the end face of the high-voltage insulation assembly 130.

[0075] Preferably, such as Figure 1 As shown, the negative electrode vacuum cover plate 110 is fitted over the outside of the insulating space, and the vacuum sealing port 111 of the negative electrode vacuum cover plate 110 is nested at the end of the negative high-voltage cathode feed channel 134. The negative electrode vacuum cover plate 110 is mounted on the main frame 140. An anode 141 is disposed inside the main frame 140.

[0076] When the negative electrode vacuum cover plate 110 is in a vacuum environment, the cathode high-voltage line and the anode 141 form a high-voltage electric field, causing the gap between the cathode high-voltage line and the negative electrode vacuum cover plate 110 in the negative high-voltage cathode feed channel 134 to form a narrow and extended breakdown path, avoiding gas breakdown between the cathode high-voltage line and the negative electrode vacuum cover plate 110. Therefore, when the radiation source delivers charged particles 143 to the high-voltage electric field through the beam collimator, ionized ions pass through the microchannel 121, are captured by the readout electrode 122, and are counted using nanodosimetry. According to a preferred embodiment, the diameter of the bottom 127 of the high-voltage protection component 120 ranges from 50 mm to 200 mm, so that ionized ions are effectively captured and collected by the microchannel 121.

[0077] Preferably, to achieve better breakdown protection, key structural details need to be added from four dimensions: electric field modulation, path extension, material synergy, and structural optimization, in order to achieve better electrical insulation performance.

[0078] First, a multi-level stepped or labyrinthine groove structure can be added to the contact interface between the first nested groove 126 and the second nested groove 133. By machining alternating bosses and grooves on the nested mating surface, the potentially straight gaps are transformed into tortuous creepage paths. The nested mating surface refers to the physical contact surface where the edge structures of the high-voltage protection component 120 and the high-voltage insulation component 130 engage during assembly, specifically formed by the mating area between the inner wall of the first nested groove 126 and the outer wall of the second nested groove 133. This nested mating surface is a key area for the two components to achieve synergistic mechanical connection and electrical insulation; its geometry and material properties directly affect the overall insulation performance. This structure significantly increases the effective path length for surface discharge, conforming to Paschen's law that the breakdown voltage increases with the length of the path. Especially in low-density gas environments of 1 Torr to 10 Torr, the extended path allows the breakdown voltage threshold to be much higher than the actual applied operating voltage of -500 V to -2500 V, thereby effectively suppressing the risk of breakdown.

[0079] Secondly, a local electric field shielding structure can be introduced at the nested mating surface. For example, an annular grounding electrode 123 or a conductive shielding layer can be provided inside the first nested slot 126 of the high-voltage protection component 120 and reliably grounded. This shielding layer can be composed of a sputtered metal film or an embedded conductive ring, and its position should be close to the edge region of the high-voltage electric field. This structure can actively homogenize the local electric field distribution, suppress electric field distortion and concentration at the nested gaps, and avoid pre-breakdown or corona discharge caused by excessively high local field strength due to small gaps.

[0080] Furthermore, micron-level sealing ridges or elastic compression structures can be incorporated into the nesting mating surfaces. For example, a micro-convex ridge can be designed around the top edge of the second nesting groove 133. When the high-voltage protection component 120 and the high-voltage insulation component 130 are pressed together, this ridge creates an interference fit with the corresponding groove wall, resulting in localized mechanical compression. If a low-permeability insulating gasket (such as a polytetrafluoroethylene film) is used in conjunction, a near-sealed physical barrier can be achieved without sacrificing electrical performance, further reducing the free path of gas in the gap and suppressing electron avalanche development. This structure is particularly suitable for high-resistivity ceramic components, compensating for minute dimensional deviations during sintering and improving interface adhesion.

[0081] Fourth, the geometric continuity of the nested structure should be optimized to avoid sharp edges or right-angle transitions. A rounded transition design with a radius of curvature of not less than 1 mm can be used at the corners of the first nested slot 126 and the second nested slot 133 to reduce the electric field gradient. Simultaneously, the transition region between the cavity 125 and the barrier portion 132 should be smooth and continuous to prevent charge accumulation at the corners. This design can reduce the local electric field enhancement factor and improve the uniformity of the overall electric field distribution, especially maintaining stability during high-voltage dynamic loading.

[0082] As mentioned above, by adding a labyrinthine nested path, introducing a grounding shielding layer, designing a micro-sealed ridge structure, optimizing the geometric transition, and matching material properties, the breakdown resistance can be significantly enhanced based on the original nested structure. These structural details work synergistically not only to extend the physical breakdown path but also to actively regulate the electric field distribution and interface state, thereby achieving more reliable and stable insulation protection performance under low pressure and high voltage conditions, providing a solid guarantee for the long-term precision operation of nanodose measurement devices.

[0083] Preferably, the high-voltage protection component 120 and the high-voltage insulation component 130 can be integrally formed. The tortuous gap originally formed by the interlocking of the first nesting groove 126 and the second nesting groove 133 needs to be realized in a single component through molding or precision machining. This integral single component should retain the cavity 125 and the through negative high-voltage cathode feed channel 134, and design a stepped or labyrinthine transition structure at the intersection of the two edges to physically force the high-voltage electric field path to be extended. Specifically, multi-level steps, sawtooth grooves, or spiral insulation channels can be set between the opening edge of the cavity 125 and the periphery of the negative high-voltage cathode feed channel 134. These structures significantly increase the surface creepage distance without increasing the overall volume, thereby forming a "bent breakdown path" equivalent to the original nested structure.

[0084] like Figure 9As shown, the horizontal axis of the left and right graphs represents the size of the ionization cluster, in μ, with a data range of 0–60. The vertical axis represents the probability density distribution, indicating the probability that an ion of radiation quality Q will produce v ionization events within a nanometer-scale volume unit, in units of 1 / event, with a data range of IE⁻⁶–0.1. The red curve is the Pv curve, which is the Bayesian reconstructed probability density distribution of the ionization cluster, and the black curve is the GEANT₄ curve, which is the GEANT₄ simulation result of the ionization cluster in a liquid water sphere. Figure 9 The left figure shows the probability density distribution of ionized clusters under a vacuum of 2.0 Torr and a sensitive volume of 4.6 nm. The right figure shows the probability density distribution of ionized clusters under a vacuum of 1.7 Torr and a sensitive volume of 3.9 nm.

[0085] The vacuum level is directly related to the size of the sensitive volume. When the sensitive volume is small, the detection efficiency of the nanodose measurement device 100 is relatively high, and the GEANT4 curve and the Bayesian curve show the best agreement. Figure 9 As shown in the right figure, under the conditions of a cathode voltage of -1500V, an anode voltage of 12V, a microchannel diameter of 1.5 mm, a vacuum degree of 1.7 Torr, and a sensitive volume of 3.9 nm, the nanodose measurement device 100 of the present invention exhibits high collection efficiency, and the GEANT4 curve shows the best agreement with the Bayesian curve. The main reason for this phenomenon is the increased detection efficiency, which further reduces the deviation between the calculated sensitive volume and the actual measured sensitive volume, thereby improving the accuracy of the actual ionization cluster size distribution calculated by the Bayesian reconstruction algorithm.

[0086] This invention also statistically analyzed the size distribution data of ionized clusters under different vacuum levels. At a vacuum level of 1.7 Torr, the total number of α particles measured was 114,335, the average size of the ionized clusters was 0.8992 μm, and the relative standard deviation of repeatability was 2.61%. At a vacuum level of 2.0 Torr, the total number of α particles measured was 104,440, the average size of the ionized clusters was 1.6050 μm, and the relative standard deviation of repeatability was 0.53%. At a vacuum level of 2.5 Torr, the total number of α particles measured was 114,840, the average size of the ionized clusters was 1.0924 μm, and the relative standard deviation of repeatability was 2.07%. Data analysis showed that the repeatability standard deviation was less than the required deviation of 6% under different cathode voltages, fully verifying the good stability of the nanodose measurement device 100 of this invention. Due to space limitations, Table 1 of this invention only shows the data on the size distribution of ionized clusters at a vacuum level of 2.0 Torr.

[0087] Table 1: Data on the size distribution of ionized clusters under a vacuum of 2.0 Torr.

[0088]

[0089] When using the nanodose measuring device 100 of the present invention, the steps of the operation method include: S1: The edge portions of the high-voltage protection component 120 and the high-voltage insulation component 130 are nested together, thereby forming an insulating space body that covers the negative high-voltage cathode feed channel 134 with the high-voltage protection component 120 and the barrier portion 132.

[0090] S2: The negative electrode vacuum cover plate 110 is fitted over the outside of the insulating space, and the vacuum sealing port 111 of the negative electrode vacuum cover plate 110 is nested at the end of the negative high voltage cathode feed channel 134.

[0091] S3: Install the negative electrode vacuum cover plate 110 on the main frame 140. An anode 141 is installed in the vacuum chamber inside the main frame 140.

[0092] When the negative electrode vacuum cover plate 110 is in a vacuum environment, the cathode high-voltage line in the negative high-voltage cathode feed channel 134 and the anode 141 form a high-voltage electric field. This creates a narrow and extended breakdown path between the cathode high-voltage line in the negative high-voltage cathode feed channel 134 and the negative electrode vacuum cover plate 110, preventing gas breakdown between the cathode high-voltage line and the negative electrode vacuum cover plate 110. Therefore, when the radiation source delivers charged particles 143 to the high-voltage electric field through the beam collimator, ionized ions pass through the microchannel 121, are captured by the readout electrode 122, and are counted using nanodosimetry. Unionized charged particles 143 are detected and captured by the primary particle detector 144.

[0093] Example 2 This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0094] This embodiment provides a nanodose measurement system, such as Figure 10 As shown, the system includes a vacuum control system 150, a nanodose measurement device 100 of the present invention, and a data acquisition and analysis system 160.

[0095] The vacuum control system 150 is used to extract air from the nanodose measuring device 100 and create a vacuum environment inside the nanodose measuring device 100.

[0096] The nanodoscopy device 100 is used to capture particles and perform nanodosimetric ionization counting.

[0097] The data acquisition and analysis system 160 is used to correlate each primary particle with its associated ionized ion and to record the arrival time of each ionized ion relative to the trigger.

[0098] Preferably, the vacuum control system 150 includes a vacuum pump unit, a vacuum level detection unit, and a logic control unit. These units work together to achieve precise control of the cavity vacuum environment and gas concentration.

[0099] Specifically, the vacuum pump unit includes a molecular pump, a first vortex pump, a second vortex pump, a first high-pressure solenoid valve, a second high-pressure solenoid valve, and a third high-pressure solenoid valve. These components are connected in a closed loop via vacuum pipes and KF interfaces. The inlet of the first vortex pump is connected to the first high-pressure solenoid valve via a vacuum pipe. The inlet of the second vortex pump is connected to the outlet of the molecular pump via a vacuum pipe. The third high-pressure solenoid valve is connected to the inlet of the molecular pump via a vacuum pipe. The other side of each high-pressure solenoid valve is connected to the outlet below the nanodosage measuring device 100 via a KF interface.

[0100] The first vortex pump is responsible for pre-evacuation, requiring the vacuum level inside the chamber to drop below 20 Pa. Since the molecular pump requires a vacuum below 10 Pa to start, the second vortex pump is designed as a secondary pump to ensure that the pressure on both the inlet and outlet sides of the molecular pump is below 10 Pa, thus guaranteeing a smooth start-up. The coordinated operation of the pump set is crucial for the stable operation of the molecular pump—starting it directly at atmospheric pressure would damage the internal blades and lead to equipment failure.

[0101] Preferably, the vacuum detection unit consists of a low vacuum pressure sensor, a high vacuum pressure sensor, and a static vacuum pressure sensor. Its core function is to monitor the vacuum status of the vacuum pipeline and cavity in real time. The specific installation location and functions are as follows: A low-vacuum pressure sensor is mounted in the first vacuum pipe between the bottom outlet and the third high-pressure solenoid valve, responsible for real-time monitoring of the vacuum level in this pipe. A high-vacuum pressure sensor is installed in the second vacuum pipe between the molecular pump and the third high-pressure solenoid valve, used to determine whether the pipe vacuum level meets the molecular pump start-up standard. A static vacuum pressure sensor is connected to the middle outlet of the nanodosage measuring device 100, used to detect the static vacuum level within the chamber. The vacuum level detection unit can accurately collect vacuum level data, efficiently cooperate with the PLC logic controller in the logic control unit to judge the current vacuum state and control the high-pressure solenoid valve, thereby coordinating with the MFC flow controller to deliver the target gas, ultimately enabling the system to achieve the preset vacuum level and gas concentration requirements.

[0102] Preferably, in accordance with the operational requirements of the vacuum control system of the nanodose measurement device 100, the PLC logic controller is configured to achieve fully automated control of the entire process, from "vacuum monitoring to logic judgment to equipment control to parameter closed-loop adjustment." Its core functions are specifically manifested as follows: The system collects real-time data from the low vacuum pressure sensor, high vacuum pressure sensor, and static vacuum pressure sensor in the vacuum degree detection unit. Simultaneously, it receives operational status feedback signals (such as start / stop status and fault signals) from the vacuum pump group (first and second vortex pumps, and molecular pump) and high-pressure solenoid valves, providing a comprehensive understanding of the system's operating conditions. Subsequently, it analyzes and judges the collected data according to a preset control program (including vacuum degree thresholds and pump group start-up logic). For example, it determines whether the first vortex pump pre-pumping has reached the target vacuum degree below 20 Pa, whether the vacuum degree in the vacuum pipeline meets the requirement of below 10 Pa for molecular pump start-up, and whether the static vacuum degree inside the cavity meets the measurement requirements, providing a basis for control actions.

[0103] The PLC logic controller outputs control commands based on the judgment results to realize the coordinated action of multiple devices. First, the first vortex pump is started for pre-evacuation. After the standard is met, the second vortex pump (molecular pump trailer pump) is started. After the molecular pump starts, it is controlled to start, so as to avoid damage to the molecular pump in a non-standard vacuum environment. At the same time, the high-pressure solenoid valve is controlled to switch the vacuum pipeline status. The MFC flow controller is coordinated to adjust the effective gas delivery flow rate so that the cavity reaches the preset vacuum degree and gas concentration.

[0104] In addition, the PLC logic controller also has fault protection and anomaly handling functions, and monitors the equipment operating status in real time. If it detects that the vacuum level is not up to standard, the pump group is faulty, or the solenoid valve is abnormal, it will immediately trigger the protection mechanism (such as stopping the relevant equipment, cutting off the high-pressure solenoid valve, and issuing an alarm signal) to avoid system damage or expansion of measurement error. At the same time, it interacts with the host computer, vacuum detection unit, MFC flow controller, etc. through the communication module, uploads real-time vacuum level data, equipment operating status and fault information, and receives parameter setting instructions (such as adjusting the target vacuum level and gas concentration) issued by the host computer, so as to realize remote monitoring and flexible control of the system.

[0105] Example 3 This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0106] This embodiment provides a high-voltage protection component 120 for the electric field insulation protection structure of a nanodose measurement device 100, including a body made of a high-resistivity material and a high-resistivity dielectric plate 124 disposed on the outside of the bottom 127 of the body.

[0107] Preferably, a cavity 125 is formed in the center of the main body from top to bottom. Preferably, at least one through-hole 128 is provided on the inner side of the bottom 127 of the cavity 125. Preferably, the bottom 127 of the cavity 125 and the wall surrounding the cavity 125 together form a stepped structure 129, which is used to confine the high-pressure protection component 120 to the edge of the vacuum chamber within the main frame 140 during assembly.

[0108] Preferably, the high-resistivity dielectric plate 124 is fixed to the outside of the bottom 127. Preferably, the high-resistivity dielectric plate 124 is provided with microchannels 121 communicating with micropores 128. Preferably, the microchannels 121 are used for the passage of ionized ions and the generation of avalanche ionization therein.

[0109] Preferably, the high-resistivity dielectric plate 124 is further provided with a readout electrode 122 located around the microchannel 121 and a ground electrode 123 arranged around the readout electrode 122. Preferably, the readout electrode 122 is used to collect the avalanche ionization signal generated through the microchannel 121. Preferably, the ground electrode 123 is grounded to form a funnel-shaped electric field distribution.

[0110] Preferably, the edge side of the high-voltage protection component 120 that contacts the high-voltage insulation component 130 is provided with a first nesting groove 126 extending circumferentially. Preferably, the first nesting groove 126 is nested with the second nesting groove 133 of the high-voltage insulation component 130, so that the high-voltage protection component 120 and the high-voltage insulation component 130 together form an insulating space covering the negative high-voltage cathode feed channel 134.

[0111] Preferably, the end face diameter of the high-resistivity dielectric plate 124 matches the diameter of the cathode 142 and the anode 141 in the nanodose measuring device 100, and the diameters of the three are in the range of 50 mm to 200 mm, so that the ionized ions generated by the ionized gas can effectively drift and be collected into the micropores 121 under the action of the electric field.

[0112] In this specific implementation, such as Figure 4 and Figure 5 As shown, the high-voltage protection component 120 in the electric field insulation protection structure of the nanodose measurement device 100 is preferably integrally formed from a high-resistivity material. Its upper part is for contact with the vacuum chamber inside the main frame 140, and its lower part is for close contact with the high-resistivity dielectric plate 124. A cavity 125 is formed from top to bottom in the center of the body. This cavity 125 is used to accommodate the barrier portion 132 from the high-voltage insulation component 130 in the assembled state, allowing the barrier portion 132 to partially extend into the cavity 125 to form a localized insulating coating. At least one through-hole 128 is machined inside the bottom 127 of the cavity 125, extending downwards through the bottom of the cavity, allowing ionized ions to enter the microchannels 121 on the high-resistivity dielectric plate 124 from the cavity area. To ensure the stability of the high-voltage protection component 120 relative to the main frame 140 during assembly, a stepped structure 129 is formed between the bottom 127 of the cavity 125 and the wall surrounding the cavity 125. Through the corresponding limiting contact between the stepped structure 129 and the main frame 140, the high-voltage protection component 120 can be precisely positioned at the edge of the vacuum chamber, ensuring the coaxiality of the structure and preventing displacement after assembly.

[0113] In this embodiment, the high-resistivity dielectric plate 124 is fixedly disposed on the outer side of the bottom 127 of the cavity, preferably by means of a high-pressure-resistant, low-stress mechanical clamp or a metal pressure frame to ensure that it does not warp under high-pressure loading and thermal cycling conditions. Multiple microchannels 121 are machined on the high-resistivity dielectric plate 124, each microchannel 121 communicating with a microhole 128 located directly above it, forming a through-structure between the microhole 128 and the microchannel 121, allowing ionized ions to enter the microchannel 121 in a straight line under the influence of an electric field. The microchannel 121 typically has a high electric field gradient, causing ionized ions to undergo avalanche ionization within it. To efficiently collect electrons generated by avalanche ionization, readout electrodes 122 are disposed on the high-resistivity dielectric plate 124 around the microchannels 121. These readout electrodes 122 are connected to the data acquisition and analysis system 160 via insulated leads, transmitting the charge signal within the microchannels 121. In addition, a grounding electrode 123 is provided on the high-resistivity dielectric plate 124, which is arranged circumferentially around the readout electrode 122. By connecting the grounding electrode 123 to the ground potential, a uniform funnel-shaped electric field distribution can be formed at the entrance of the microchannel 121, so that the electric field lines narrow from wide and concentrate towards the central region of the microchannel 121, thereby enhancing the directional drift of ionized ions to the microchannel 121 and improving the charge collection efficiency.

[0114] To ensure effective cooperation between the high-voltage protection component 120 and the high-voltage insulation component 130, a first nesting groove 126 extending circumferentially is machined on the edge of the high-voltage protection component 120 near the high-voltage insulation component 130. The size and shape of the first nesting groove 126 match the second nesting groove 133 of the high-voltage insulation component 130. In the assembled state, the first nesting groove 126 and the second nesting groove 133 are nested together, forming an insulation path with a complex folding structure between the high-voltage protection component 120 and the high-voltage insulation component 130, and further constructing an insulating space between them that covers the negative high-voltage cathode feed channel 134. This interlocking structure not only enhances the stability of the mechanical fit and prevents relative displacement between the high-voltage insulation component 130 and the high-voltage protection component 120 under the action of a high-voltage electric field, but also significantly extends the possible breakdown path from the negative high-voltage cathode feed channel 134 to the surrounding metal structure, thereby significantly improving the overall electrical breakdown resistance of the system.

[0115] In this embodiment, the end face diameter of the high-resistivity dielectric plate 124 is preferably matched with the diameters of the cathode 142 and anode 141 in the nanodose measurement device 100, so that the three are coaxially arranged in the axial direction, and the corresponding diameter range is set to 50 mm to 200 mm. By keeping the size of the high-resistivity dielectric plate 124 on the same order of magnitude as the anode 141 and cathode 142, a symmetrical electric field distribution on a macroscale can be formed when the device is working, so that ionized ions passing through the working gas can drift towards the microchannel 121 along symmetrical and stable electric field lines under the action of the electric field. Especially in the low-density tissue equivalent gas (low-pressure gas) environment, the migration direction of ionized ions is very sensitive. If the electric field distribution is uneven, the ions will deviate from the entrance of the microchannel 121 and cannot enter the microchannel, resulting in a decrease in signal acquisition efficiency. This embodiment ensures the symmetry of the macroscopic electric field distribution by matching the diameter, so that the ionized ions generated by gas ionization can be stably guided to the central region of the microchannel 121, effectively improving the utilization rate of ionized ions and enhancing the stability and repeatability of the avalanche ionization signal.

[0116] The high-voltage protection component 120, constructed using the structure described in this embodiment, provides efficient collection of ionized ions in weak ionization and low-voltage operating environments. Furthermore, in conjunction with the structural features of the first nested groove 126, this component, together with the high-voltage insulation component 130, forms a stable structure that extends the insulation path. This comprehensively improves the high-voltage loading capacity, breakdown resistance, ion collection efficiency, and statistical measurement accuracy of the nanodose measurement device 100. These technical effects are difficult to achieve in traditional dielectric substrate and single-layer nanodose detectors, representing a significant improvement over existing technologies.

[0117] Example 4 This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0118] This embodiment provides a high-voltage insulation component 130 for use in the electric field insulation protection structure of a nanodose measurement device 100. The high-voltage insulation component 130 is made of a high-resistivity material and has a solid structure with a negative high-voltage cathode feed channel 134 running through its center. The portion not penetrated by the negative high-voltage cathode feed channel 134 forms a barrier portion 132.

[0119] Preferably, the negative high-voltage cathode feed channel 134 extends axially along the high-voltage insulation component 130. Preferably, the negative high-voltage cathode feed channel 134 is located at the center of the high-voltage insulation component 130. Preferably, one end of the negative high-voltage cathode feed channel 134 protrudes from the end face of the high-voltage insulation component 130 to form a cathode inlet 131, which is used to cooperate with the vacuum sealing port 111 of the negative electrode vacuum cover plate 110.

[0120] Preferably, the edge side of the high-voltage insulation component 130 is provided with a second nesting groove 133 in the circumferential direction, which is used to nest with the first nesting groove 126 of the high-voltage protection component 120 in the assembled state, so that a tortuous and extended creepage path is formed between the high-voltage insulation component 130 and the high-voltage protection component 120.

[0121] Preferably, the barrier portion 132 extends along the axial direction of the negative high-voltage cathode feed channel 134 toward the side closer to the high-voltage protection component 120, and is adapted to at least partially extend into the cavity 125 of the high-voltage protection component 120 in the assembled state, so as to jointly construct an insulating space covering the negative high-voltage cathode feed channel 134 with the high-voltage protection component 120.

[0122] Preferably, when the high-voltage insulation component 130 is assembled in the nanodose measuring device 100, the distance between the bottom end face of the barrier portion 132 and the cathode 142 is limited to the range of 0.5 mm to 5 mm, so as to form a stable funnel-shaped electric field distribution between the cathode 142 and the anode 141. In conjunction with the depth of the second nested groove 133 being 5 mm to 20 mm, the breakdown path between the cathode high-voltage line through the negative high-voltage cathode feed channel 134 and the negative electrode vacuum cover plate 110 is narrow and extended, thereby suppressing the occurrence of gas breakdown.

[0123] In this specific implementation, such as Figure 6 and Figure 7 As shown, the high-voltage insulation component 130 in the electric field insulation protection structure of the nanodose measurement device 100 is made entirely of a high-resistivity material. Its body is a solid structure, formed into a continuous and dense structure through integral sintering or integral processing of the insulation material. A negative high-voltage cathode feed channel 134 is axially disposed at the center of the high-voltage insulation component 130. This negative high-voltage cathode feed channel 134 is used to accommodate the cathode high-voltage line introduced from the external vacuum in the assembled state, enabling it to stably provide a high-voltage potential to the cathode 142 inside the device. To ensure a reliable seal between the power supply path and the external vacuum interface, the high-voltage insulation assembly 130 has a cathode inlet 131 protruding from the end face at one end near the negative electrode vacuum cover plate 110. The cathode inlet 131 is an extension of the negative high-voltage cathode power supply channel 134 at the end of the assembly. Its geometry is adapted to the shape and size of the inner hole of the vacuum sealing port 111 of the negative electrode vacuum cover plate 110, so that the two can form a stable vacuum sealing structure through precise nesting after assembly, which significantly reduces the free gas space at the negative pressure interface and improves the dielectric strength when the cathode high-voltage line is introduced into the vacuum.

[0124] The high-voltage insulation component 130 has a second nesting groove 133 machined circumferentially on its peripheral sidewall. The second nesting groove 133 is preferably an annular groove, and its cross-sectional shape can be rectangular, chamfered, or arc-shaped. During assembly, the second nesting groove 133 can interlock with the corresponding first nesting groove 126 on the high-voltage protection component 120, forming an irregular, tortuous, extended interface between the high-voltage insulation component 130 and the high-voltage protection component 120. The contact surface between the two exhibits a folded structure in both the axial and radial directions. This interlocking relationship effectively increases the creepage distance between the high-voltage insulation component 130 and the high-voltage protection component 120, forming a labyrinth-like extended insulation path, and creating a complete, high-impedance insulation covering around the high-voltage area, effectively suppressing creepage breakdown along the surface and improving the overall structure's anti-breakdown performance.

[0125] In this embodiment, the portion of the high-voltage insulation component 130 not penetrated by the negative high-voltage cathode feed channel 134 serves as a barrier portion 132. This barrier portion 132 forms a continuous insulating wall inside the high-voltage insulation component 130 and extends axially along the negative high-voltage cathode feed channel 134 towards the side closer to the high-voltage protection component 120, until it at least partially extends into the cavity 125 of the high-voltage protection component 120 in the assembled state. With this structure, the barrier portion 132 spatially surrounds the negative high-voltage cathode feed channel 134, ensuring the feed path is completely enclosed within the insulator. Furthermore, the barrier portion 132, extending into the cavity 125, further isolates the high-voltage region from the external metal structure, causing the electric field lines to redistribute in the feed lead-out area. This significantly weakens the electric field tip effect common in conventional feed hole structures and reduces charge concentration near the high-voltage line.

[0126] Specifically, when the high-voltage insulation component 130 is assembled in the nanodose measuring device 100, the axial distance between the bottom end face of the barrier portion 132 and the cathode 142 inside the device is preferably controlled within the range of 0.5 mm to 5 mm. This distance range was determined through extensive electric field simulation and experimental verification. It can ensure that the funnel-shaped electric field structure near the cathode 142 is well formed, so that the electric field lines converge smoothly from the cathode 142 towards the microchannel 121, while avoiding the barrier portion 132 being too close to the cathode 142, which would cause a sharp increase in the local electric field and thus trigger the risk of partial discharge or breakdown. Meanwhile, the depth of the second nesting groove 133 in the high-voltage insulation component 130 is preferably 5 mm to 20 mm. This depth can provide sufficient nesting stroke in actual use, so that a sufficient return path is formed between the high-voltage insulation component 130 and the high-voltage protection component 120, extending the insulation creepage distance along the interface. Combined with the insulation performance of the high-resistivity material body, the breakdown path from the negative high-voltage cathode feed channel 134 to the negative electrode vacuum cover plate 110 is forcibly lengthened and compressed and restricted in space, further improving the overall structure's resistance to breakdown.

[0127] This embodiment, through the above structural design, enables the high-voltage insulation component 130, after assembly, to form an insulating space with the high-voltage protection component 120, enclosing the negative high-voltage cathode feed channel 134. The high-voltage region is surrounded by continuous high-resistivity material, with no air gap accumulation inside, thereby avoiding the formation of easily discharged free gas regions. Simultaneously, due to the high fit between the cathode inlet 131 and the vacuum seal 111, the free path under negative pressure is significantly shortened, reducing the number of gas molecules. This allows a stable high-voltage operating environment to be maintained even in low-voltage ranges prone to breakdown, such as 1 Torr to 10 Torr. The combined effect of the deep insertion of the barrier portion 132 into the center of the negative high-voltage cathode feed channel 134, the labyrinthine structure formed by the second nested groove 133, and the integral molding of the high-resistivity material significantly improves the breakdown voltage of the feed path. The high-voltage loading capacity can stably reach -1500 V to -2500 V without gas breakdown, achieving performance unattainable by traditional straight-hole structures. Based on this, the overall electric field distribution between the cathode 142 and the anode 141 is more uniform, making the migration path of ionized ions more regular, increasing the probability of them entering the micropore 121, and making the avalanche ionization process more stable and reliable, thereby significantly improving the detection accuracy and repeatability of the nanodose measurement device 100.

[0128] Example 5 This embodiment is a further improvement on embodiment 1, and repeated content will not be described again.

[0129] This embodiment provides a high-voltage insulation component 130 for use in the electric field insulation protection structure of a nanodose measurement device 100. The high-voltage insulation component 130 is made of a high-resistivity material and has a solid structure with a negative high-voltage cathode feed channel 134 running through its center. The portion not penetrated by the negative high-voltage cathode feed channel 134 forms a barrier portion 132.

[0130] Preferably, the negative high-voltage cathode feed channel 134 extends along the axial direction of the high-voltage insulation component 130 and is located at the center of the high-voltage insulation component 130. Preferably, one end of the negative high-voltage cathode feed channel 134 protrudes from the end face of the high-voltage insulation component 130 to form a cathode inlet 131, which is used to cooperate with the vacuum sealing port 111 of the negative electrode vacuum cover plate 110.

[0131] Preferably, the edge side of the high-voltage insulation component 130 is provided with a second nesting groove 133 in the circumferential direction, which is used to nest with the first nesting groove 126 of the high-voltage protection component 120 in the assembled state, so that a tortuous and extended creepage path is formed between the high-voltage insulation component 130 and the high-voltage protection component 120.

[0132] Preferably, the barrier portion 132 extends along the axial direction of the negative high-voltage cathode feed channel 134 toward the side closer to the high-voltage protection component 120, and is adapted to at least partially extend into the cavity 125 of the high-voltage protection component 120 in the assembled state, so as to jointly construct an insulating space covering the negative high-voltage cathode feed channel 134 with the high-voltage protection component 120.

[0133] When the high-voltage insulation component 130 is assembled in the nanodose measuring device 100, the distance between the bottom end face of the barrier portion 132 and the cathode 142 is limited to the range of 0.5mm to 5mm, so as to form a stable funnel-shaped electric field distribution between the cathode 142 and the anode 141. In conjunction with the depth of the second nested groove 133 of 5mm to 20mm, the breakdown path between the cathode high-voltage line through the negative high-voltage cathode feed channel 134 and the negative electrode vacuum cover plate 110 is narrow and extended, thereby suppressing the occurrence of gas breakdown.

[0134] In one specific implementation, such as Figure 6 and Figure 7As shown, the high-voltage insulation component 130 in the electric field insulation protection structure of the nanodose measurement device 100 is made entirely of a high-resistivity material. Its body is a solid structure, formed into a continuous and dense structure through integral sintering or integral processing of the insulation material. A negative high-voltage cathode feed channel 134 is axially disposed at the center of the high-voltage insulation component 130. This negative high-voltage cathode feed channel 134 is used to accommodate the cathode high-voltage line introduced from the external vacuum in the assembled state, enabling it to stably provide a high-voltage potential to the cathode 142 inside the nanodose measurement device 100. To ensure a reliable seal between the power supply path and the external vacuum interface, the high-voltage insulation assembly 130 has a cathode inlet 131 protruding from the end face at one end near the negative electrode vacuum cover plate 110. The cathode inlet 131 is an extension of the negative high-voltage cathode power supply channel 134 at the end of the assembly. Its geometry is adapted to the shape and size of the inner hole of the vacuum sealing port 111 of the negative electrode vacuum cover plate 110, so that the two can form a stable vacuum sealing structure through precise nesting after assembly, which significantly reduces the free gas space at the negative pressure interface and improves the dielectric strength when the cathode high-voltage line is introduced into the vacuum.

[0135] The high-voltage insulation component 130 has a second nesting groove 133 machined circumferentially on its peripheral sidewall. The second nesting groove 133 is preferably an annular groove, and its cross-sectional shape can be rectangular, chamfered, or arc-shaped. During assembly, the second nesting groove 133 can interlock with the corresponding first nesting groove 126 on the high-voltage protection component 120, forming an irregular, tortuous, extended interface between the high-voltage insulation component 130 and the high-voltage protection component 120. The contact surface between the two exhibits a folded structure in both the axial and radial directions. This interlocking relationship effectively increases the creepage distance between the high-voltage insulation component 130 and the high-voltage protection component 120, forming a labyrinth-like extended insulation path, and creating a complete, high-impedance insulation covering around the high-voltage area, effectively suppressing creepage breakdown along the surface and improving the overall structure's anti-breakdown performance.

[0136] In this embodiment, the portion of the high-voltage insulation component 130 not penetrated by the negative high-voltage cathode feed channel 134 serves as a barrier portion 132. This barrier portion 132 forms a continuous insulating wall inside the high-voltage insulation component 130 and extends axially along the negative high-voltage cathode feed channel 134 towards the side closer to the high-voltage protection component 120, until it at least partially extends into the cavity 125 of the high-voltage protection component 120 in the assembled state. With this structure, the barrier portion 132 spatially surrounds the negative high-voltage cathode feed channel 134, ensuring the feed path is completely enclosed within the insulator. Furthermore, the barrier portion 132, extending into the cavity 125, further isolates the high-voltage region from the external metal structure, causing the electric field lines to redistribute in the feed lead-out area. This significantly weakens the electric field tip effect common in conventional feed hole structures and reduces charge concentration near the high-voltage line.

[0137] Specifically, when the high-voltage insulation component 130 is assembled in the nanodose measuring device 100, the axial distance between the bottom end face of the barrier portion 132 and the cathode 142 inside the nanodose measuring device 100 is preferably controlled within the range of 0.5 mm to 5 mm. This distance range was determined through extensive electric field simulation and experimental verification. It ensures that the funnel-shaped electric field structure near the cathode 142 is well formed, so that the electric field lines converge smoothly from the cathode 142 towards the microchannel 121. It also avoids the barrier portion 132 being too close to the cathode 142, which could cause a sharp increase in the local electric field and thus trigger the risk of partial discharge or breakdown. Meanwhile, the depth of the second nesting groove 133 in the high-voltage insulation component 130 is preferably 5 mm to 20 mm. This depth can provide sufficient nesting stroke in actual use, so that a sufficient return path is formed between the high-voltage insulation component 130 and the high-voltage protection component 120, extending the creepage distance along the interface. Combined with the insulation performance of the high-resistivity material body, the breakdown path from the negative high-voltage cathode feed channel 134 to the negative electrode vacuum cover plate 110 is forcibly lengthened and compressed and restricted in space, further improving the overall structure's resistance to breakdown.

[0138] This embodiment, through the above structural design, enables the high-voltage insulation component 130, after assembly, to form an insulating space with the high-voltage protection component 120, enclosing the negative high-voltage cathode feed channel 134. The high-voltage region is surrounded by continuous high-resistivity material, with no air gap accumulation inside, thereby avoiding the formation of easily discharged free gas regions. Simultaneously, due to the high fit between the cathode inlet 131 and the vacuum seal 111, the free path under negative pressure is significantly shortened, reducing the number of gas molecules. This allows a stable high-voltage operating environment to be maintained even in low-voltage ranges prone to breakdown, such as 1 Torr to 10 Torr. The combined effect of the deep insertion of the barrier portion 132 into the center of the negative high-voltage cathode feed channel 134, the labyrinthine structure formed by the second nested groove 133, and the integral molding of the high-resistivity material significantly improves the breakdown voltage of the feed path. The high-voltage loading capacity can stably reach -1500 V to -2500 V without gas breakdown, achieving performance unattainable by traditional straight-hole structures. Based on this, the overall electric field distribution between the cathode 142 and the anode 141 is more uniform, making the migration path of ionized ions more regular, increasing the probability of them entering the micropore 121, and making the avalanche ionization process more stable and reliable, thereby significantly improving the detection accuracy and repeatability of the nanodose measurement device 100.

[0139] It should be noted that the specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this invention, and these solutions all fall within the scope of this invention and its protection. Those skilled in the art should understand that this specification and its accompanying drawings are illustrative and not intended to limit the scope of the claims. The scope of protection of this invention is defined by the claims and their equivalents. This specification contains multiple inventive concepts; terms such as "preferredly," "according to a preferred embodiment," or "optionally" indicate that the corresponding paragraph discloses an independent concept. The applicant reserves the right to file divisional applications based on each inventive concept.

Claims

1. A nanodose measuring device, the device comprising a main frame (140) and an electric field insulation protection structure; characterized in that, The electric field insulation protection structure includes a negative electrode vacuum cover plate (110), a high voltage protection component (120), and a high voltage insulation component (130) installed on the main frame (140). The high-voltage protection component (120) has a cavity (125) in the center and a high-resistivity dielectric plate (124) on the outside of the bottom (127) of the cavity (125). The high-voltage insulation component (130) is provided with a negative high-voltage cathode feed channel (134) that penetrates itself, so that the unpenetrated part of the high-voltage insulation component (130) forms a barrier part (132). The edge portions of the high voltage protection component (120) and the high voltage insulation component (130) are nested together, thereby the high voltage protection component (120) and the barrier portion (132) form an insulating space covering the negative high voltage cathode feed channel (134); The negative electrode vacuum cover plate (110) is sleeved on the outside of the insulating space body, and the vacuum sealing port (111) of the negative electrode vacuum cover plate (110) is nested at the end of the negative high voltage cathode feed channel (134); The negative electrode vacuum cover plate (110) is installed on the main frame (140); an anode (141) is provided inside the main frame (140). When the negative electrode vacuum cover plate (110) is in a vacuum environment, the cathode high voltage line that passes through the negative high voltage cathode feed channel (134) and is connected to the cathode (142) forms a high voltage electric field with the anode (141), which makes the gap between the cathode high voltage line and the negative electrode vacuum cover plate (110) form a narrow and extended breakdown path, thus avoiding gas breakdown between the cathode high voltage line and the negative electrode vacuum cover plate (110).

2. The nanodose measuring device according to claim 1, characterized in that, The edge of the high-voltage protection component (120) that is in contact with the high-voltage insulation component (130) is provided with a first nesting groove (126). The edge of the high-voltage insulation component (130) is provided with a second nesting groove (133). The high-voltage protection component (120) and the high-voltage insulation component (130) are interlocked with each other through the first nesting slot (126) and the second nesting slot (133), wherein the cavity (125) accommodates at least a portion of the barrier portion (132).

3. The nanodose measuring device according to claim 1 or 2, characterized in that, The negative high-voltage cathode feed channel (134) is located in the center of the high-voltage insulation component (130) and protrudes from one end of the high-voltage insulation component (130); The shape and size of the vacuum sealing port (111) of the negative electrode vacuum cover plate (110) are adapted to the protruding part of the negative high voltage cathode feed channel (134).

4. The nanodosage measuring device according to any one of claims 1 to 3, characterized in that, The negative high voltage cathode feed channel (134) is in the shape of a straight channel; The microchannel (121) in the center of the high-resistivity dielectric plate (124) is approximately coincident with the axial centerline of the negative high-voltage cathode feed channel (134); When a funnel-shaped electric field is formed between the cathode high-voltage line and the anode (141), ionized ions generated by the ionized gas drift toward the high-voltage protection component (120) and enter the microchannel (121).

5. The nanodosage measuring device according to any one of claims 1 to 4, characterized in that, The high-voltage protection component (120) is made of high-resistance materials, including epoxy resin, ceramic, polymer insulating materials and sapphire crystal materials. The bottom (127) of the high-voltage protection component (120) has a diameter ranging from 50 mm to 200 mm, so that ionized ions can be effectively captured and collected by the micropores (121).

6. The nanodosage measuring device according to any one of claims 1 to 5, characterized in that, The pore size of the microchannel (121) ranges from 0.5 mm to 10 mm, and the depth of the microchannel (121) ranges from 3 mm to 30 mm, so that the ionized ions entering the microchannel (121) generate an avalanche ionization signal in the microchannel (121).

7. The nanodosage measuring device according to any one of claims 1 to 6, characterized in that, The high-voltage insulation component (130) is made of high-resistance materials, including epoxy resin, ceramic, polymer insulation materials and sapphire crystal materials; The distance between the bottom end face of the barrier portion (132) in the high-voltage insulation assembly (130) and the cathode (142) is in the range of 0.5mm to 5mm; The depth range of the first nested groove (126) of the high-voltage protection component (120) is 5mm to 20mm; The depth of the second nested groove (133) in the high-voltage insulation component (130) ranges from 5mm to 20mm.

8. A method for measuring nanodosage, characterized in that, The method includes: The edge portions of the high-voltage protection component (120) and the high-voltage insulation component (130) are nested together, thereby forming an insulating space covering the negative high-voltage cathode feed channel (134) with the high-voltage protection component (120) and the barrier portion (132). The high-voltage protection component (120) has a cavity (125) in the center, and a high-resistivity dielectric plate (124) is provided on the outer side of the bottom (127) of the cavity (125). The high-voltage insulation component (130) has a negative high-voltage cathode feed channel (134) that penetrates itself, so that the unpenetrated portion of the high-voltage insulation component (130) forms the barrier portion (132). The negative electrode vacuum cover plate (110) is fitted over the outside of the insulating space body, and the vacuum seal port (111) of the negative electrode vacuum cover plate (110) is nested at the end of the negative high voltage cathode feed channel (134); The negative electrode vacuum cover plate (110) is installed on the main frame (140); an anode (141) is provided inside the main frame (140). When the negative electrode vacuum cover plate (110) is in a vacuum environment, the cathode high voltage line that passes through the negative high voltage cathode feed channel (134) and is connected to the cathode (142) forms a high voltage electric field with the anode (141), which makes the gap between the cathode high voltage line and the negative electrode vacuum cover plate (110) form a narrow and extended breakdown path, thus avoiding gas breakdown between the cathode high voltage line and the negative electrode vacuum cover plate (110).

9. The method according to claim 8, characterized in that, The edge of the high-voltage protection component (120) that is in contact with the high-voltage insulation component (130) is provided with a first nesting groove (126). The edge of the high-voltage insulation component (130) is provided with a second nesting groove (133). The high-voltage protection component (120) and the high-voltage insulation component (130) are interlocked with each other through the opposing first nesting slot (126) and second nesting slot (133). The cavity (125) accommodates at least a portion of the barrier (132), and the microchannel (121) is positioned opposite to the radial cross-section of the negative high voltage cathode feed channel (134).

10. A nanodose measurement system, characterized in that, The system includes: A vacuum control system (150) is used to extract air from the nanodose measuring device (100) and create a vacuum environment inside the nanodose measuring device (100); A nanodoscopy device (100) is used to capture particles and perform nanodosimetric ionization counting; A data acquisition and analysis system (160) is used to correlate each primary particle with its associated ionized ion and record the arrival time of each ionized ion relative to the trigger. The nanodose measuring device (100) includes a main frame (140) and an electric field insulation protection structure; the electric field insulation protection structure includes a negative electrode vacuum cover plate (110), a high voltage protection component (120) and a high voltage insulation component (130) installed on the main frame (140). A cavity (125) is provided in the center of the high-voltage protection assembly (120), and a high-resistivity dielectric plate (124) is provided on the outside of the bottom (127) of the cavity (125). The high-voltage insulation component (130) is provided with a negative high-voltage cathode feed channel (134) that penetrates itself, so that the unpenetrated part of the high-voltage insulation component (130) forms a barrier part (132). The edge portions of the high voltage protection component (120) and the high voltage insulation component (130) are nested together, thereby the high voltage protection component (120) and the barrier portion (132) form an insulating space covering the negative high voltage cathode feed channel (134); The negative electrode vacuum cover plate (110) is fitted over the outside of the insulating space, and the vacuum seal port (111) of the negative electrode vacuum cover plate (110) is nested at the end of the negative high voltage cathode feed channel (134); The negative electrode vacuum cover plate (110) is installed on the main frame (140); the main frame (140) is provided with an anode (141). When the negative electrode vacuum cover plate (110) is in a vacuum environment, the cathode high voltage line that runs through the negative high voltage cathode feed channel (134) and is connected to the cathode (142) forms a high voltage electric field with the anode (141), which makes the gap between the cathode high voltage line and the negative electrode vacuum cover plate (110) form a narrow and extended breakdown path, thus avoiding gas breakdown between the cathode high voltage line and the negative electrode vacuum cover plate (110).

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