Particle detection device and image generation device

Abstract

A particle detecting apparatus according to the present embodiment includes a detector including a plurality of superconducting nanostrips, which detects a particle from a particle generating source; a conversion mechanism having channels corresponding to the plurality of superconducting nanostrips, which converts an analog signal from a corresponding superconducting nanostrip into a digital signal; a collection mechanism, which collects outputs from the conversion mechanism; a first temperature maintaining section, which maintains a first temperature below a superconducting transition temperature; a first cryogenic container, which accommodates the first temperature maintaining section; and a vacuum container, which accommodates the conversion mechanism and the first cryogenic container, has an opening portion through which the particle from the particle generating source passes, and accommodates the detector inside the first cryogenic container and connects the detector to the first temperature maintaining section, the conversion mechanism is maintained at the first temperature or higher, and the collection mechanism is disposed outside the first cryogenic container.

Description

[0001] Related applications

[0002] This application is based on and claims the benefit of priority arising from the prior Japanese Patent Application No. 2021-060979, filed on March 31, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments of the present invention relate to a particle detection device and an image generation device. Background Technology

[0004] A particle detection device using a superconducting single-photon detector (SSPD) is known. This particle detection device generates a pulse signal when an X-ray photon collides with one of the multiple superconducting nanostrips that make up the SSPD. The number of photons (particles) is detected by counting the number of pulses in the generated pulse signal.

[0005] However, the SSPD is maintained in an extremely low-temperature container below the superconducting transition temperature. Therefore, when the mechanism for counting pulse signals (the counter) is located at room temperature, the heat flow from room temperature to the container increases. Especially when the SSPD is used in an image generation device, it is necessary to set the number of superconducting nanostrips to 100 or more. Summary of the Invention

[0006] One embodiment of the present invention provides a particle detection device capable of suppressing heat flow, and an image generation device using the particle detection device.

[0007] The particle detection device according to this embodiment includes: a detector containing multiple superconducting nanostrips for detecting particles from a particle source; a conversion mechanism having channels corresponding to the multiple superconducting nanostrips for converting analog signals from the corresponding superconducting nanostrips into digital signals; a collection mechanism for collecting the output from the conversion mechanism; a first temperature maintaining unit for maintaining a first temperature below the superconducting transition temperature; a first cryogenic container housing the first temperature maintaining unit; and a vacuum container housing the conversion mechanism and the first cryogenic container, having an opening for the particles from the particle source to pass through, the detector being housed within the first cryogenic container and connected to the first temperature maintaining unit, the conversion mechanism being maintained at a temperature above the first temperature, and the collection mechanism being disposed outside the first cryogenic container.

[0008] Based on the above configuration, a particle detection device capable of suppressing heat flow and an image generation device using the particle detection device can be provided. Attached Figure Description

[0009] Figure 1 This is a cross-sectional view showing the particle detection device according to the first embodiment.

[0010] Figure 2 This is a circuit diagram showing the particle detection device of the first embodiment.

[0011] Figure 3 It is a three-dimensional diagram illustrating the operating principle of a particle detection device.

[0012] Figure 4 It is a waveform diagram illustrating the operating principle of the particle detection device.

[0013] Figure 5 This is a waveform diagram representing the output of the particle detection device.

[0014] Figure 6 This is a cross-sectional view showing the particle detection device involved in the first modification of the first embodiment.

[0015] Figure 7 This is a cross-sectional view showing the particle detection device involved in the second variation of the first embodiment.

[0016] Figure 8 This is a cross-sectional view showing the particle detection device involved in the third variation of the first embodiment.

[0017] Figure 9 This is a cross-sectional view showing the particle detection device involved in the fourth variation of the first embodiment.

[0018] Figure 10 This is a cross-sectional view showing the particle detection device involved in the fifth modification of the first embodiment.

[0019] Figure 11 This is a circuit diagram illustrating the particle detection device involved in the sixth variation of the first embodiment.

[0020] Figure 12 This is a cross-sectional view showing the particle detection device according to the second embodiment.

[0021] Figure 13 This is a circuit diagram illustrating the particle detection device according to the third embodiment.

[0022] Figure 14 This is a circuit diagram illustrating the particle detection device according to the fourth embodiment.

[0023] Figure 15 This is a cross-sectional view showing the particle detection device according to the fifth embodiment.

[0024] Figure 16 This is a cross-sectional view of a particle detection device according to a variation of the fifth embodiment.

[0025] Figure 17 This is a cross-sectional view showing a particle detection device according to another variation of the fifth embodiment.

[0026] Figure 18 This is a block diagram illustrating the image generation apparatus according to the sixth embodiment. Detailed Implementation

[0027] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc., may not necessarily be the same as the actual situation. Even when representing the same part, it may be represented in the drawings with different dimensions, proportions, etc.

[0028] (First Embodiment) Figure 1 The configuration of the particle detection device according to the first embodiment is shown. The particle detection device 100 of the first embodiment includes a superconducting single-photon detector (SSPD) 110, a constant current power supply 120, a conversion mechanism 130, a collection mechanism 140, a cooling mechanism 150, and a computer 160.

[0029] The cooling mechanism 150 includes a first cryogenic container 152, a second cryogenic container 154 that houses the first cryogenic container 152, a vacuum container 156 that houses the second cryogenic container 154, and a freezer 170.

[0030] The cryostat 170 includes a first temperature maintaining unit 172 and a second temperature maintaining unit 174, and performs freezing in two stages. The first temperature maintaining unit 172 is housed in a first cryogenic container 152. The second temperature maintaining unit 174 is housed in a second cryogenic container 154. The SSPD 110 is connected to the first temperature maintaining unit 172 and is maintained at a temperature T1 below the superconducting transition temperature of the superconducting material constituting the SSPD 110.

[0031] The conversion mechanism 130 is connected to the second temperature maintenance unit 174 and is maintained at a temperature T2 that is above temperature T1. For example, when the superconducting material is niobium, temperature T1 is in the range of 20% to the superconducting transition temperature (1.84 to 9.2 K), for example, around 4 K. Temperature T2 is below 100 K, for example, around 65 K. Windows 152a and 154a are respectively provided on the first cryogenic container 152 and the second cryogenic container 154, which allow the detected particles to pass through and block heat. When the detected particles are hard X-ray photons, aluminum foil or the like is used for the windows. Similarly, the vacuum container 156 is provided with an opening 156a. In addition, the vacuum container 156 is connected to the vacuum container 190 that contains the particle generation source 180. The vacuum level of the vacuum container 156 is preferably 1.0 × 10⁻⁶. －6 Below mbar.

[0032] like Figure 2 As shown, the SSPD 110 forms N (N≧2) linear superconducting nanostrips 202 parallel to each other and at equal intervals on a substrate 201 such as a silicon wafer. Here, N is a natural number. For example, niobium is used as the superconducting material constituting the superconducting nanostrips 202.

[0033] like Figure 2 As shown, the conversion mechanism 130 includes a biaser 204, an amplifier 205, and a comparator 206, each corresponding to one of the N superconducting nanostrips 202. These biasers 204, amplifiers 205, and comparators 206 are, for example, disposed on a printed circuit board 203. Additionally, the conversion mechanism 130 includes a counter 207 disposed on the printed circuit board 203, having N channels corresponding to the N superconducting nanostrips 202, and connected to the N comparators 206.

[0034] Each superconducting nanostrip 202 has one end grounded and the other end connected to the RF / DC terminal of the corresponding bias circuit 204. The DC terminal of the bias circuit 204 is connected to the constant current power supply 120. The RF terminal of the bias circuit 204 is connected to the input terminal of the corresponding amplifier 205. The output terminal of the amplifier 205 is connected to the input terminal of the corresponding comparator 206. The output terminal of the comparator 206 is connected to the input terminal of the counter 207.

[0035] The collection mechanism 140 includes, for example, a centralized distribution circuit 209 disposed on a printed circuit board 208. The input terminals of the centralized distribution circuit 209 receive the output signal from the counter 207. The output terminals of the centralized distribution circuit 209 are connected to the computer 160. Furthermore, the counter 207 and the centralized distribution circuit 209 are semiconductor circuits, manufactured using FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuits), or the like. Additionally, the collection mechanism 140 is housed in a region outside the second cryogenic container 154 and within the vacuum container 156. In this case, the centralized distribution circuit 209 is cooled, for example, by a Peltier element 210.

[0036] (The operating principle of a particle detection device) Below, refer to... Figure 3 and Figure 4 Explain the operating principle of the particle detection device 100. For example... Figure 3 As shown, X-ray photons and other particles 301 generated from particle source 180 collide with a superconducting nanostrip 202. In the superconducting nanostrip 202, a current, as indicated by arrow 302, flows from constant current power supply 120 via bias device 204, to a level not exceeding the superconducting critical current. Bias device 204 functions as a device for applying DC without affecting high-frequency signals. A region 303, transitioning from superconductivity to normal conduction, forms near the point of collision of particles 301 in the superconducting nanostrip 202. Because region 303 is in a normal conducting state and has resistance, current 304 flows around region 303. Thus, region 305, where the current becomes denser due to this detour, exceeds the superconducting critical current. Therefore, region 305 transitions to normal conduction, the superconducting nanostrip 202 becomes blocked, generating resistance, and a temporary voltage rise occurs. Subsequently, due to cooling, region 305 returns to the superconducting state. This voltage change generates a pulse signal. The pulse signal is amplified by amplifier 205. When the size of the amplified pulse signal 401 is above the threshold 402, a rectangular wave 404 with a pulse width 403 of about 100 nanoseconds is output from comparator 206.

[0037] Counter 207 is equipped with a section to record the count value of each channel. If a rectangular wave 404 arrives at counter 207, the count value of the corresponding channel is incremented by 1. Thus, counter 207 records the count value of each of the N superconducting nanostrips.

[0038] If the centralized distribution circuit 209 receives a start command from the computer 160, it resets the count values ​​of all channels recorded by the counter 207 to 0. It repeats the following actions: after a predetermined period of time, it reads the count value from the counter 207 and transmits the count values ​​of all channels to the computer 160, and then resets the count values ​​of all channels to 0 again.

[0039] If a termination command is received from computer 160, the operation ends. This is achieved by plotting counts for the positions of the superconducting nanostrips corresponding to each channel. Figure 5 The figure shows the one-dimensional positional distribution of the number of particles reaching SSPD 110.

[0040] By moving the SSPD 110 relative to the particle source 180 while acquiring a one-dimensional position distribution, a two-dimensional position distribution of the number of particles arriving at the SSPD 110 can be obtained. In the case of X-ray photons, this two-dimensional position distribution is equivalent to an X-ray image.

[0041] The pulse signal generated from SSPD 110 is Figure 4 The half-width 405 shown is, for example, an analog signal of about 2 nanoseconds (equivalent to a frequency of 500MHz). Therefore, as the cable 211 connecting SSPD 110 and conversion mechanism 130, a high-speed transmission flexible substrate with low high-frequency signal loss and space-saving multiple lines is used. In addition, the high-speed transmission flexible substrate is formed in a structure in which the ground line is arranged around the signal line, like a coaxial cable. If the total cross-sectional area of ​​the conductive parts (signal line and ground line) is set as S, the length of the high-speed transmission flexible substrate is set as L, and the thermal conductivity of the material constituting the conductive parts is set as k, then the heat W transferred by the signal line and the ground line is expressed by the following formula (1).

[0042] [Equation 1]

[0043]

[0044] Since the heat transferred outside the conductive part (insulation part) of the cable 211 is almost negligible, the material, cross-sectional area S, and length L of the conductive part of the cable 211 are determined in such a way that the heat W is sufficiently small (for example, less than 1 / 10) compared to the cooling capacity of the first temperature maintenance part 172 of the refrigerator 170.

[0045] On the other hand, the signal used for communication between the aggregation mechanism 140 and the conversion mechanism 130 is a digital signal with a pulse width of approximately 5 microseconds (200kHz). Generally, the higher the signal frequency, the smaller the cross-sectional area of ​​the conductive portion of a single signal line, and the longer the distance, the greater the energy loss of the signal. In addition, compared with analog signals, even if there is some degree of loss, the impact of digital signals is smaller because their values ​​are "0" or "1". Therefore, the cable 212 connecting the conversion mechanism 130 and the aggregation mechanism 140 is made of a flexible substrate with a smaller cross-sectional area of ​​the conductive portion compared with the high-speed transmission flexible substrate, a flat cable, or a twisted pair cable, etc., to minimize heat flow.

[0046] The effects of the first embodiment will now be explained. The cooling capacity of the second temperature maintenance unit 174 of the refrigerator 170 is around tens of W, which is extremely high compared to the cooling capacity of the first temperature maintenance unit 172, which is less than 1 W. In this embodiment, by connecting the switching mechanism 130 to the second temperature maintenance unit 174, even if the heat generated by the switching mechanism 130 is large, it can be adequately cooled. In addition, compared to the case where the switching mechanism 130 is disposed outside the vacuum container 156, the length of the cable 211 connecting the SSPD 110 to the switching mechanism 130 is shorter, and even if the cross-sectional area of ​​a single signal line is small, losses can be adequately suppressed.

[0047] Since the total cross-sectional area of ​​the conductive parts is determined by the cooling capacity of the first temperature maintenance part 172 as described above, if the cross-sectional area of ​​a single signal line becomes smaller, the number of signal lines may increase. As a result, a larger number of SSPDs 110 can be mounted with superconducting nanostrips 202.

[0048] Furthermore, by placing the collection mechanism 140 outside the second cryogenic container 154, the burden on the cooling capacity of the second temperature maintenance unit 174 can be reduced. By housing the collection mechanism 140 inside the vacuum container 156, cooling can be achieved using the Peltier element 210 without condensation.

[0049] As described above, according to the first embodiment, the pulse count of a large number of SSPDs 110 based on a semiconductor circuit with high heat generation can be counted using the conversion mechanism 130 and the collection mechanism 140, and a one-dimensional positional distribution of the particle number over a larger range can be obtained in a single operation. That is, a particle detection device that can suppress heat flux and allows for multi-line configuration of superconducting nanostripes can be provided.

[0050] Furthermore, a method was also considered that uses a superconducting single-flux quantum circuit as a counter, and that suppresses heat flux by placing it in an extremely low-temperature environment, similar to an SSPD. However, unlike this embodiment, there is a problem that there is no practical experience in constructing superconducting single-flux quantum circuits into large-scale components.

[0051] The particle detection device according to the modified example of the first embodiment will now be described.

[0052] (First variation) Figure 6 The particle detection device according to the first modification is shown. The particle detection device 100A of this first modification has the following configuration: Figure 1 In the particle detection device 100 of the first embodiment shown, the conversion mechanism 130 is connected to the first temperature maintenance unit 172, and the collection mechanism 140 is connected to the second temperature maintenance unit 174.

[0053] (Second variation) Figure 7 The particle detection device according to the second modification is shown. The particle detection device 100B of this second modification has the following configuration: Figure 6 In the particle detection device 100A of the first modified example shown, the collecting mechanism 140 is disposed outside the second cryogenic container 154 and inside the vacuum container 156.

[0054] (3rd variation) Figure 8 The particle detection device involved in the third modification is shown. The particle detection device 100C of this third modification has the following configuration: Figure 7 In the particle detection device 100B of the second modified example shown, the collecting mechanism 140 is disposed outside the vacuum container 156.

[0055] (4th variation) Figure 9 The particle detection device according to the fourth modification is shown. The particle detection device 100D of this fourth modification has the following configuration: Figure 6 In the particle detection device 100A of the first modified example shown, the conversion mechanism 130 is connected to the second temperature maintenance unit 174.

[0056] (5th variation) Figure 10 The particle detection device according to the fifth modification is shown. The particle detection device 100E of this fifth modification has the following configuration: Figure 9 In the particle detection device 100D of the fourth modified example shown, the collection mechanism 140 is disposed outside the vacuum container 156.

[0057] In the first to fifth modifications, the optimal configuration can be achieved based on the operating temperature range of the conversion mechanism 130 and the collection mechanism 140, the heat generation, and the cooling capacity of the first temperature maintenance unit 172 and the second temperature maintenance unit 174.

[0058] like Figure 8 or Figure 10As shown in the third and fifth modifications, when the collecting mechanism 140 is placed outside the vacuum container 156, a cooling fan and cooling water are used instead of the Peltier element 210 for cooling the centralized distribution circuit 209. In this case, it has the advantages of increasing the cooling temperature, visually confirming the status of the centralized distribution circuit 209, and easily making setting changes.

[0059] like Figure 7 As shown in the second variation, when the conversion mechanism 130 is connected to the first temperature maintaining unit 172 and the collecting mechanism 140 is disposed outside the second cryogenic container 154 and inside the vacuum container 156, or when it is disposed outside the vacuum container 156 as shown in the third variation, the second temperature maintaining unit 174 and the second cryogenic container 154 are not necessarily required.

[0060] (Sixth variation) such as Figure 9 As shown in the fourth variation, when both the conversion mechanism 130 and the collection mechanism 140 are connected to the second temperature maintaining unit 174, as... Figure 11 As shown in the sixth variation, the conversion mechanism 130 and the collection mechanism 140 can also be formed on a single substrate, and the counter and centralized distribution circuit can be manufactured using a single FPGA or ASIC 601. In this case, space is saved.

[0061] (Second Embodiment) Refer to Figure 12 This describes the particle detection device according to the second embodiment. The particle detection device 100F of this second embodiment replaces... Figure 1 The two-stage refrigerator 110 shown uses a first refrigerator 702 and a second refrigerator 705. The first refrigerator 702 has a first temperature maintaining unit 701 that maintains the temperature at T1, and the first temperature maintaining unit 701 is housed in a first cryogenic container 703. The second refrigerator 705 has a second temperature maintaining unit 704 that maintains the temperature at T2. The second temperature maintaining unit 704 is housed in a second cryogenic container 706, and the first cryogenic container 703 and the second cryogenic container 706 are arranged side by side in a vacuum container. In this case, the cooling capacity of the second temperature maintaining unit 704 can be increased, and the limitation on the heat generation of the conversion mechanism 130 can be alleviated.

[0062] (Third Embodiment) Hereinafter, referring to Figure 13 This describes the particle detection device according to the third embodiment. Figure 1 and Figure 2 In the particle detection device 100 of the first embodiment shown, the conversion mechanism 130 is provided with N biasers 204, amplifiers 205, comparators 206 and counters 207 on a substrate 203.

[0063] In contrast, the particle detection device of this third embodiment divides the conversion mechanism 130 into m-plate substrates. For example... Figure 13 As shown, n1, n2, ..., n are respectively disposed on m printed circuit boards 801. m A bias circuit 204, an amplifier 205, a comparator 206, and a circuit with n1, n2, ..., n m A counter with 802 channels. Here, N = n1 + n2 + ... + n m Each superconducting nanostrip 202 is connected to a biaser 204, an amplifier 205, a comparator 206, and a channel of a counter 802. Each of the m counters 802 is connected to a centralized distribution circuit 803 on the aggregation mechanism 140. Their respective functions and other configurations are the same as those described in the first embodiment.

[0064] The particle detection device of the third embodiment can also be applied when the number N of superconducting nanostrips 202 exceeds the number of channels of counter 802, and can achieve the same effect as the first embodiment. It has the effect of further expanding the range of the one-dimensional positional distribution of the number of particles that can be acquired in a single burst.

[0065] (Fourth Embodiment) Hereinafter, referring to Figure 14 This describes the particle detection device according to the fourth embodiment. Figure 1 and Figure 2 In the first embodiment shown, the conversion mechanism 130 is composed of a bias 204, an amplifier 205, a comparator 206, and a counter 207.

[0066] In the fourth embodiment, such as Figure 14 As shown, the conversion mechanism 901 includes N biasers 204, amplifiers 205, and comparators 206. The collection mechanism 902 includes a counter 903 and a centralized distribution circuit 904. Alternatively, the counter 903 can be divided into m parts, or as shown... Figure 12 As shown in the seventh variation, the counter 903 and the centralized distribution circuit 904 are manufactured using an FPGA or ASIC.

[0067] The signal generated by comparator 206 is a rectangular wave with a pulse width of approximately 100 nanoseconds. It is binary data, i.e., a digital signal, indicating whether a pulse signal was generated from SSPD 110. Since information is not lost even with slight losses, a cable with a small cross-sectional area can be used for the cable 905 connecting the conversion mechanism 901 and the collection mechanism 904. Furthermore, in the amplifier 205 described above, if the pulse signal can be amplified to a sufficient degree to compensate for the amount of loss in the cable connecting the conversion mechanism 901 and the collection mechanism 904, the comparator 206 can be omitted, and the comparator 206 can be placed in the collection mechanism instead of the conversion mechanism. Other configurations are the same as in the first embodiment.

[0068] According to the fourth embodiment, the same effect can be obtained in a different manner than that of the first embodiment. In this case, it has the effect of being able to use devices with an operating temperature range near room temperature as comparators, counters, and centralized distribution circuits.

[0069] (Fifth Embodiment) Hereinafter, referring to Figure 15 This describes the particle detection device according to the fifth embodiment. Figure 1 In the first embodiment shown, the conversion mechanism 130 is connected to the second temperature maintenance unit 174.

[0070] In the particle detection device 100G of the fifth embodiment, a connector 1000 is provided at the midpoint between the SSPD 110 and the conversion mechanism 130, and the connector 1000 is connected to the second temperature maintaining section 174 to maintain the temperature of the connector at T2. The connector 1000 can be omitted at this time, but in order to maintain the temperature of the cable (conductive part) at the portion connected to the second temperature maintaining section 174 at T2, the connection area between the cable and the second temperature maintaining section 174 needs to be sufficiently large. The conversion mechanism 130 is disposed outside the second cryogenic container 154 and inside the vacuum container 156, and is cooled by the Peltier element 1001 (see reference). Figure 15 ).

[0071] In addition, such as Figure 16 or Figure 17 As shown in the variation of the fifth embodiment, the conversion mechanism 130 and the collection mechanism 140 can also be disposed outside the vacuum container 156. In this case, they are cooled by a cooling fan and cooling water. Let the heat transferred by the cable connecting the SSPD 110 and the connector 1000 be W. s The heat transferred by the cable 1002 connecting the connector 1000 and the conversion mechanism 130 is set as W. c So that W c Greater than W sThe length, cross-sectional area, material, and mounting position of the connector 1000 of the conductive portion of the cable 1002 are determined in a manner that is less than the cooling capacity of the second temperature maintaining section 174. Since the cooling capacity of the second temperature maintaining section is sufficiently large, the cross-sectional area of ​​the conductive portion of the cable 1002 can be sufficiently large, thereby effectively suppressing signal loss transmitted by the cable 1002.

[0072] According to the fifth embodiment and its variations, the conversion mechanism can be disposed outside the cryogenic container, which has the effect of mitigating the limitation on the operating temperature of the conversion mechanism.

[0073] (Sixth Embodiment) Refer to Figure 18 The image generation apparatus according to the sixth embodiment will be described. This sixth embodiment's image generation apparatus includes, for example, a particle source 180 that generates X-rays, one of the particle detection apparatuses of the first to fifth embodiments and their modifications (e.g., the particle detection apparatus 100 of the first embodiment), and a controller 1100 that moves the sample 10 relative to the SSPD 110 of the particle detection apparatus 100. The sample 10 is positioned between the particle source 180 and the SSPD 110, and X-rays are irradiated onto the sample 10 from the particle source 180. The SSPD 110 detects the X-rays passing through the sample 10. At this time, by moving the sample 10 relative to the SSPD 110 using the controller 1100, an X-ray image of the sample 10 can be obtained. For example, if the length and width of the superconducting nanostrip are the same, and the relative movement is along the extension direction of the superconducting nanostrip, a two-dimensional image of the sample 10 can be obtained. When the relative movement is a rotational movement relative to the centerline connecting the center of SSPD 110 and the center of particle source 180, a 2D image of sample 10 can be obtained. This image is generated by computer 160. Alternatively, image generation can also be performed using a computer (not shown) configured outside of particle detection device 100.

[0074] Since the image generation apparatus of the sixth embodiment uses one of the particle detection apparatuses of the first to fifth embodiments and their variations, it is possible to obtain an image generation apparatus that can suppress heat flux and allows for multi-line configuration of superconducting nanostrips.

[0075] Several embodiments of the present invention have been described, but these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are included within the scope of the invention as described in the patent claims and its equivalents.

Claims

1. A particle detecting apparatus comprising: a detector including a plurality of superconducting nanostrips, which detects particles from a particle generating source; a conversion mechanism having channels provided corresponding to the plurality of superconducting nanostrips, which converts analog signals from the corresponding superconducting nanostrips into digital signals; a collection mechanism which collects outputs from the conversion mechanism; a first temperature maintaining section which maintains a first temperature below a superconducting transition temperature; a first cryogenic container which accommodates the first temperature maintaining section; and a vacuum container which accommodates the conversion mechanism and the first cryogenic container, has an opening portion through which the particles from the particle generating source pass, the detector is accommodated in the first cryogenic container and connected to the first temperature maintaining section, the conversion mechanism is maintained at or above the first temperature, and the collection mechanism is disposed outside the first cryogenic container. Further comprising: a second temperature maintaining section which maintains a second temperature above the first temperature; and a second cryogenic container which accommodates the second temperature maintaining section and accommodates the first cryogenic container, and is accommodated in the vacuum container.

3. The particle detecting apparatus according to claim 2, wherein the conversion mechanism is accommodated in the second cryogenic container and connected to the second temperature maintaining section.

4. The particle detecting apparatus according to claim 1, wherein the conversion mechanism is accommodated in the first cryogenic container and connected to the first temperature maintaining section.

5. The particle detecting apparatus according to any one of claims 1 to 4, wherein the collection mechanism is accommodated in the vacuum container.

6. The particle detecting apparatus according to claim 2 or 3, wherein the collection mechanism is disposed in the second cryogenic container and connected to the second temperature maintaining section.

7. The particle detecting apparatus according to any one of claims 1 to 4, wherein the collection mechanism is disposed outside the vacuum container. Further comprising: a second temperature maintaining section which maintains a second temperature above the first temperature; and a second cryogenic container which accommodates the second temperature maintaining section and accommodates the first cryogenic container in parallel, in the vacuum container.

9. The particle detecting apparatus according to claim 1, wherein, with respect to a cable connected to the detector, a value obtained by dividing a product of a cross-sectional area of a conductive portion of the cable, a temperature difference between both ends of the cable, and a thermal conductivity of the conductive portion by a length of the cable is 1 / 10 or less of a cooling capacity in the first temperature maintaining section.

2. The particle detection apparatus of claim 1, wherein, 10. A particle detecting apparatus comprising: a detector including a plurality of superconducting nanostrips, which detects particles from a particle generating source; a conversion mechanism having channels provided corresponding to the plurality of superconducting nanostrips, which converts analog signals from the corresponding superconducting nanostrips into digital signals; a collection mechanism which collects outputs from the conversion mechanism; a cable which connects the detector and the conversion mechanism; a first temperature maintaining section which maintains a first temperature below a superconducting transition temperature; a first cryogenic container which accommodates the first temperature maintaining section; and a second temperature maintaining section which maintains a second temperature above the first temperature. Further comprising: a second cryogenic container which accommodates the second temperature maintaining section and accommodates the first cryogenic container. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 8. The particle detection apparatus of claim 1, wherein, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A second temperature maintaining unit maintains a second temperature above the first temperature; and A vacuum container, which houses the first cryogenic container and the second temperature maintaining section, has an opening for the particles from the particle generation source to pass through. The detector is housed within the first cryogenic container and connected to the first temperature maintenance unit. The cable is connected to the second temperature maintaining unit, and the portion of the cable connected to the second temperature maintaining unit is maintained at the second temperature. The collection mechanism is located outside the first cryogenic container.

11. The particle detection device according to claim 10, wherein, A connector is provided at the midpoint of the cable connecting the detector and the conversion mechanism. The connector is connected to a second temperature maintaining unit and is maintained at a second temperature. The heat transferred by the cable connecting the detector and the connector is less than the heat transferred by the cable connecting the connector and the conversion mechanism.

12. The particle detection device according to any one of claims 1 to 4, 10 to 11, wherein, The pulse width of the digital signal output from the conversion mechanism is 50 ns or more.

13. The particle detection device according to any one of claims 1 to 4, 10 to 11, wherein, The multiple superconducting nanostrips are divided into multiple groups, and the conversion mechanism is divided into groups corresponding to each group and arranged side by side. The analog signals generated from the superconducting nanostrips belonging to each group are input into the conversion mechanism corresponding to each group.

14. The particle detection device according to any one of claims 1 to 4, 10 to 11, wherein, The cable connecting the detector to the conversion mechanism is a flexible substrate.

15. The particle detection device according to any one of claims 1 to 4, 10 to 11, wherein, The conversion mechanism has: A biasing device, which is configured corresponding to the plurality of superconducting nanostrips, applies DC to the output signal from the corresponding superconducting nanostrips; An amplifier that amplifies the output of the bias circuit; A comparator that compares whether the output of the amplifier is above a threshold, and outputs a digital signal when it is above the threshold. as well as A counter that counts the output from the comparator.

16. An image generation apparatus comprising: The particle detection device according to any one of claims 1 to 15; The particle source; A controller that causes the detector of the particle detection device to move relative to the sample; and The image generation unit generates an image of the sample based on the output of the collection mechanism.

Images