Iron-based x-ray dual-mode energy recovery system

Abstract

The application provides an iron-based X-ray double-mode energy recovery system and relates to the technical field of photovoltaic devices.The application is based on the high atomic number characteristics of an iron-based metal substrate and the three-dimensional structure of a honeycomb cavity array, a heterojunction is formed through an iron base, a titanium nitride transition layer, a cadmium sulfide electronic transition layer and a cadmium telluride crystal layer, the high-efficiency binding and capture of secondary electrons by the heterojunction improves the X-ray absorption rate and the photoelectric conversion efficiency, reduces the material use cost, has the advantage of easy processing, solves the problems of high cost and complex preparation of traditional radiation energy recovery materials, and through the dynamic complementation of the photovoltaic channel and the piezoelectric channel, high-power rapid energy supply can be realized through the photovoltaic layer under strong X-ray irradiation, and the piezoelectric and thermoelectric units can continuously output micro energy under weak radiation or pulse intermittent scenes, so that the energy collection stability and reliability in complex working conditions such as security inspection machines are ensured.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic device technology, specifically to an iron-based X-ray dual-mode energy recovery system. Background Technology

[0002] Active battery-powered IoT tags typically power their chips, sensors, and communication modules via built-in chemical batteries. However, this method suffers from difficulties in battery replacement and high maintenance costs. Consequently, passive tags have been developed, such as those powered by solar energy or radio frequency wireless power transmission. However, in environments with metal shielding, electromagnetic signals suffer severe shielding and attenuation, rendering these power extraction methods completely ineffective. Existing X-ray detectors are only used for imaging or material identification, and their value as an energy source for powering passive devices has not been explored.

[0003] Currently, X-ray energy recovery has certain drawbacks. X-ray energy recovery is often based on photovoltaic technology: using semiconductor materials such as cadmium telluride to directly convert X-ray photons into electrical energy. Existing solutions mostly use planar structures, which have low absorption efficiency for highly penetrating X-rays, and the expensive single-crystal materials lead to high costs, making it difficult to apply on a large scale. Thermoelectric technology: using materials such as bismuth telluride to generate electricity using the thermal gradient generated by X-rays, but it requires a stable and large temperature difference to work effectively. In transient and pulsed security inspection X-ray scenarios, the temperature rise is limited, the conversion efficiency is extremely low, and the thermal inertia is large, resulting in a slow response speed.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide an iron-based X-ray dual-mode energy recovery system to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The iron-based X-ray dual-mode energy recovery system includes a radiation absorption pretreatment layer, a direct power generation layer, an indirect conversion layer, and a power management module. A honeycomb cavity array is formed on the surface of the radiation absorption pretreatment layer; The direct power generation layer includes a titanium nitride transition layer, a cadmium sulfide electron transition layer, and a cadmium telluride crystal layer, which are sequentially deposited on the inner wall of the honeycomb cavity array. The indirect conversion layer is coupled to the bottom of the iron base layer of the X-ray absorption pretreatment layer and is used to convert the heat energy generated after absorbing X-rays into electrical energy. The indirect conversion layer includes a piezoelectric conversion unit and a thermoelectric conversion unit. The piezoelectric conversion unit is used to convert the transient thermal deformation generated by X-ray irradiation of the iron base layer into electrical energy, and the thermoelectric conversion unit is used to generate supplementary power in the case of steady-state temperature difference. The power management module is electrically connected to the direct power generation layer and the indirect conversion layer, respectively. The power management module includes a dual-channel dynamic rectification circuit and a switching circuit.

[0007] Furthermore, the depth-to-width ratio of the honeycomb cavity array is greater than 2:1 and less than 5:1.

[0008] Furthermore, the titanium nitride transition layer and the cadmium sulfide electron transition layer are sequentially deposited on the inner wall of the honeycomb cavity array by magnetron sputtering, and the cadmium telluride crystal layer is deposited on the cadmium sulfide electron transition layer by closed-space sublimation.

[0009] Furthermore, the piezoelectric conversion unit is composed of two sets of lead zirconate titanate ceramic sheets arranged in a row. One end of each set of lead zirconate titanate ceramic sheets is rigidly fixed to an anchor point on the iron substrate by a ceramic support, and the other end is coupled to the iron substrate by a flexible thermally conductive silicone. The two sets of lead zirconate titanate ceramic sheets are arranged orthogonally at a 45-degree angle, and the thermoelectric conversion unit is disposed between the piezoelectric conversion units.

[0010] Furthermore, the dual-channel dynamic rectifier circuit includes a synchronous rectifier circuit and a voltage doubler rectifier circuit. The synchronous rectifier circuit is used to reduce rectification conduction losses and improve energy harvesting efficiency, while the voltage doubler rectifier circuit is used to increase the AC pulse voltage output by the piezoelectric conversion unit.

[0011] Furthermore, the switching circuit is electrically connected to the photovoltaic channel, the piezoelectric channel, and the energy storage capacitor, respectively.

[0012] Compared with the prior art, the beneficial effects of the present invention are: This invention is based on the high atomic number characteristics of an iron-based metal substrate and the three-dimensional structure of a honeycomb cavity array. It constructs a heterojunction by forming an iron-based substrate, a titanium nitride transition layer, a cadmium sulfide electron transition layer, and a cadmium telluride crystal layer. Combined with the efficient trapping of secondary electrons by the heterojunction, it improves X-ray absorption rate and photoelectric conversion efficiency while reducing material costs and offering the advantage of easy processing. This solves the problems of high cost and complex preparation of traditional radiation energy recovery materials. At the same time, through the dynamic complementarity of photovoltaic and piezoelectric channels, it can achieve high-power rapid energy supply through the photovoltaic layer under strong X-ray irradiation, and can continuously output micro-energy through piezoelectric and thermoelectric units in weak radiation or pulse intermittent scenarios. With the help of the power management module, it effectively eliminates the sensitivity of a single transduction mode to X-ray intensity and energy spectrum fluctuations, ensuring the stability and reliability of energy collection in complex working environments such as security inspection machines. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall system flow of the present invention; Figure 2 This is a schematic diagram of a partial cross-sectional structure of the present invention; Figure 3 This is a schematic diagram of the working mode of the passive security inspection tag of the present invention. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0015] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0016] Example: Please refer to Figure 1-3 The present invention provides a technical solution: The iron-based X-ray dual-mode energy recovery system includes a radiation absorption pretreatment layer, a direct power generation layer, an indirect conversion layer, and a power management module. A honeycomb-shaped cavity array is formed on the surface of the X-ray absorption pretreatment layer; The direct power generation layer includes a titanium nitride transition layer, a cadmium sulfide electron transition layer, and a cadmium telluride crystal layer, which are sequentially deposited on the inner wall of the honeycomb cavity array. The indirect conversion layer is coupled to the bottom of the iron base layer of the X-ray absorption pretreatment layer to convert the heat energy generated after absorbing X-rays into electrical energy. The indirect conversion layer includes a piezoelectric conversion unit and a thermoelectric conversion unit. The piezoelectric conversion unit is used to convert the transient thermal deformation generated by X-ray irradiation of the iron base layer into electrical energy, and the thermoelectric conversion unit is used to generate supplementary power in the case of steady-state temperature difference. The power management module is electrically connected to the direct power generation layer and the indirect conversion layer respectively. The power management module includes a dual-channel dynamic rectification circuit and a switching circuit.

[0017] The X-ray absorption pretreatment layer forms the substrate, which is made of iron. It is formed by short-pulse laser etching to create a honeycomb cavity array with a density of 500-1000 cells / cm². The depth-to-width ratio of the honeycomb cavity array is greater than 2:1 and less than 5:1, for example, with a diameter of 20μm and a depth of 50μm. This can greatly increase the specific surface area and pre-absorb X-rays and generate secondary electrons through the high atomic number characteristics of iron.

[0018] Titanium nitride transition layers and cadmium sulfide electron transition layers are sequentially deposited on the inner wall of the honeycomb cavity array via magnetron sputtering. A cadmium telluride crystal layer is then deposited onto the cadmium sulfide electron transition layer using a closed-space sublimation method. This forms a pn junction perpendicular to the cavity surface, changing the traditional planar structure to a three-dimensional structure. This effectively traps secondary electrons, which bounce multiple times within the microcavity and are captured by the PN junction, improving capture efficiency and thus enhancing photoelectric conversion efficiency.

[0019] The piezoelectric conversion unit consists of two sets of lead zirconate titanate (PZT) ceramic sheets. One end of each set is rigidly fixed to an anchor point on an iron substrate via a ceramic support, while the other end is coupled to the iron substrate via flexible thermally conductive silicone with a specific Young's modulus (e.g., 5 MPa). The two sets of PZT sheets are arranged orthogonally at a 45-degree angle. The shear force generation mechanism is as follows: When the iron substrate expands due to absorbing X-ray heat, due to isotropic expansion, a small, randomly oriented in-plane strain is generated on the substrate plane. Through an asymmetric constraint design with one end rigidly fixed and the other end elastically coupled, this in-plane strain is converted into shear stress (d15 mode) acting on the PZT sheets. The 45° orthogonal arrangement ensures that regardless of the direction of thermal deformation, at least one set of PZT sheets is effectively shear-driven, thereby outputting charge. A thermoelectric conversion unit, which is a bismuth telluride thermoelectric element, is positioned between the piezoelectric conversion units.

[0020] The dual-channel dynamic rectifier circuit includes a synchronous rectifier circuit and a voltage doubler rectifier circuit. The synchronous rectifier circuit is used to reduce rectification conduction losses and improve energy harvesting efficiency. The voltage doubler rectifier circuit is used to increase the AC pulse voltage output by the piezoelectric conversion unit to a voltage level sufficient to wake up the power management module or drive the charge pump. The cadmium telluride crystal as the photovoltaic layer is a low internal resistance source, while the lead zirconate titanate ceramic sheet as the piezoelectric layer is a high internal resistance source. The power management module is equipped with a low input impedance synchronous rectifier circuit for the photovoltaic channel and a high input impedance charge pump and voltage doubler rectifier circuit for the piezoelectric channel. The piezoelectric channel accumulates and doubles the piezoelectric micro-pulse charge through the high input impedance charge pump connected in series with the voltage doubler rectifier circuit, forming a stable DC voltage that can drive the energy storage capacitor, thereby maximizing the piezoelectric output energy and thus maximizing energy transfer.

[0021] The power management module utilizes a cascaded startup mechanism of the photovoltaic and piezoelectric layers to achieve cold start. The high-voltage synchronous rectification circuit is directly coupled to the photovoltaic layer. Utilizing the high-amplitude voltage (greater than 1.8V) output by the photovoltaic layer at the moment of X-ray incident, the internal energy storage capacitor is rapidly charged, thus completing power-on within microseconds. This voltage also serves as a bias power supply, activating the piezoelectric conversion unit interface and conditioning circuit (including a high-impedance charge pump) that were originally in a dormant state. As a result, any weak piezoelectric pulse energy can be rectified and multiplied through this activated path, working together with the photovoltaic energy to maintain the capacitor voltage above the undervoltage lockout threshold (~1.8V) of the power management module. Thanks to the optimized circuit architecture, the startup and energy capture response time is less than 100μs, far lower than the typical security inspection X-ray pulse width, thus ensuring that the energy is completely captured during the pulse's duration.

[0022] The switching circuit is electrically connected to the photovoltaic channel, the piezoelectric channel, and the energy storage capacitor, respectively, and is configured to execute the following energy routing strategy: High-voltage direct connection mode: Triggered when the real-time monitoring photovoltaic channel input voltage is greater than 3V, corresponding to strong X-ray irradiation, the high-voltage synchronous rectifier circuit is controlled to conduct, directly coupling the photovoltaic layer to the energy storage capacitor and the load, utilizing the low internal resistance characteristics of the photovoltaic layer to supply power and charge quickly with maximum power transmission efficiency; Micro-energy boost mode: When the input voltage of the photovoltaic channel is no greater than 3V, and the piezoelectric and thermoelectric channels detect a valid pulse output trigger, the direct connection path of the photovoltaic is disconnected, and the high impedance voltage doubler rectifier circuit of the piezoelectric channel is activated. The micro-amplitude, high internal resistance pulse energy output by the piezoelectric layer is multiplied and accumulated, and the energy storage capacitor is charged in trickle form to maintain the basic operating conditions of the system of the present invention. Reverse blocking and regulated output: The switching circuit includes a reverse blocking unit to prevent the energy in the energy storage capacitor from flowing back to the energy source. Regardless of the mode, the output of the switching circuit is connected to a voltage regulator to output a constant stable voltage (such as 3.3V) to power the ultra-low power Bluetooth communication module.

[0023] Reference Figure 1 This is the control logic diagram for the power management module.

[0024] Reference Figure 2 From top to bottom, the layers are: X-ray absorption pretreatment layer, direct power generation layer, indirect conversion layer, piezoelectric conversion unit, and hot spot conversion unit.

[0025] Specifically, the X-ray absorption pretreatment layer uses industrial pure iron plate as the substrate, with a thickness of 300 μm. A fiber laser with a wavelength of 1064 nm is used to etch the substrate surface, forming a hexagonal honeycomb microcavity array with a density of 800 microcavities / cm². Each microcavity has an opening diameter of 20 μm, a depth of 50 μm, and an aspect ratio of 2.5:1. The choice of industrial pure iron as the substrate material represents a balance between atomic number Z=26, mechanical strength, thermal conductivity, and processing cost. Compared to lead or aluminum, it is more conducive to secondary electron emission and heat conduction, and lead is toxic, while aluminum has a low atomic number. After processing, the microcavities undergo electrochemical polishing to reduce the surface roughness to below 0.1 μm, thereby decreasing the carrier recombination probability.

[0026] On the microcavity structure obtained above, a functional layer is deposited using magnetron sputtering. First, a 50 nm thick titanium nitride layer is sputtered as a transition layer to buffer the difference in thermal expansion coefficients between the iron substrate and the semiconductor layer. Second, a 50 nm thick cadmium sulfide layer is sputtered as an n-type window layer. Finally, a p-type cadmium telluride crystal layer is grown using an improved closed-space sublimation method. To solve the problem of sidewall film formation in high aspect ratio microcavities, substrate rotation and tilted argon gas flow are introduced during the deposition process, allowing cadmium telluride gas molecules to enter the microcavity at a grazing angle, thereby forming a continuous and uniform polycrystalline thin film on the sidewalls up to 50 μm deep, establishing a pn junction structure perpendicular to the cavity surface, which serves as the direct power generation layer.

[0027] The indirect conversion layer uses PZT-5H type piezoelectric ceramic material, namely lead zirconate titanate ceramic sheets, cut into ceramic sheets with dimensions of 20mm × 5mm × 0.2mm. These ceramic sheets serve as piezoelectric conversion units. Two ceramic sheets are arranged at a 45° angle and fixed to the bottom of the iron-based absorption layer using flexible thermally conductive silicone. This asymmetric constraint structure ensures that when the iron substrate undergoes thermal deformation due to X-ray absorption, regardless of the deformation direction, it can drive the PZT-5H type piezoelectric ceramic material to produce shear deformation, thereby outputting charge. Thermoelectric conversion units can be selectively arranged between the piezoelectric conversion units for supplementary power generation under steady-state temperature difference scenarios.

[0028] The power management module uses a PMIC chip, which integrates a dual-channel dynamic rectification and switching circuit. Specifically, the photovoltaic channel is connected to the photovoltaic layer and configured with a full-bridge synchronous rectification circuit; the piezoelectric channel is connected to the piezoelectric layer and configured with a six-times voltage multiplier rectifier circuit to accumulate weak pulse charges. Both outputs are connected to a 22μF energy storage capacitor.

[0029] The logic control unit of the PMIC chip is configured to execute dynamic switching logic: real-time monitoring of the input voltage of the photovoltaic channel; when the input voltage is greater than 3V, it is determined to be a high-voltage scenario, and the photovoltaic channel is enabled first (high-voltage direct drive mode); when the input voltage is not greater than 3V and the piezoelectric channel has micro-pulse output, it is determined to be a low-energy scenario, and the piezoelectric channel is switched to (accumulated micro-pulse mode).

[0030] The iron-based X-ray dual-mode energy recovery system, along with a low-power Bluetooth module, temperature sensor, and encryption chip, are encapsulated in a 25mm x 25mm x 3mm ABS engineering plastic shell to form a complete passive security inspection tag.

[0031] It also integrates an X-ray triggered TDMA communication protocol: the tag begins collecting energy when it detects an X-ray pulse, and wakes up and transmits data within a specific time window after the pulse ends, such as 1ms to 20ms, avoiding conflicts with other tags and achieving synchronization using the periodic operation of the X-ray machine. A self-destructive data erasure mechanism based on radiation dose rate is also included: when an abnormally high dose rate is detected, such as greater than 50mGy / s, which may correspond to an unpacking inspection, the circuit automatically triggers to erase sensitive data, ensuring information security.

[0032] When high-energy X-rays are incident on the surface of the X-ray absorption pretreatment layer, the iron-based material absorbs the X-rays and simultaneously excites secondary electrons, generating heat energy. The secondary electrons bounce multiple times within the honeycomb cavity array and are captured by the direct power generation layer on the sidewall, thus forming a photoelectric current. At the same time, the heat energy drives the piezoelectric conversion unit of the indirect conversion layer to output pulse charges. After being processed by the dual-channel dynamic rectification and switching logic of the power management module, the photoelectric and piezoelectric signals are rectified into stable DC and converged to the energy storage capacitor, ultimately powering the low-power Bluetooth communication module and sensors, achieving reliable energy recovery in a metal-shielded environment.

[0033] Reference Figure 3The passive security tag's workflow is as follows: When luggage bearing this tag enters the X-ray irradiation area of ​​the security scanner, the X-ray absorption preprocessing layer captures high-energy X-rays and converts the radiation energy into electrical energy to charge the energy storage capacitor through a dual-mode conversion mechanism of the direct power generation layer and the indirect conversion layer. The tag controller follows the communication protocol, delaying for 1ms after detecting the end of the X-ray pulse to avoid the strongest noise interference, and waking up the low-power Bluetooth communication module within a time window of 1ms-20ms. The pre-stored 12-byte unique ID code and the real-time collected 4-byte ambient temperature data are encrypted and compressed by AES and broadcast. The Bluetooth reader deployed at the exit of the security scanner receives and uploads the data to the background management system, thereby completing the automatic identification, matching, and tracking of luggage. At the same time, the tag has a built-in dose rate sensor. When the ambient X-ray dose rate is detected to continuously exceed 50mGy / s, indicating that it may be undergoing manual inspection, a self-destruct circuit will be triggered to automatically erase the sensitive data in the encryption chip to ensure information security.

[0034] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0035] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented in software, the above embodiments can be implemented, in whole or in part, as a computer program product. Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0036] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment, depending on actual needs.

[0037] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. An iron-based X-ray dual-mode energy recovery system, comprising a radiation absorption pretreatment layer, a direct power generation layer, an indirect conversion layer, and a power management module, characterized in that: A honeycomb cavity array is formed on the surface of the radiation absorption pretreatment layer; The direct power generation layer includes a titanium nitride transition layer, a cadmium sulfide electron transition layer, and a cadmium telluride crystal layer, which are sequentially deposited on the inner wall of the honeycomb cavity array. The indirect conversion layer is coupled to the bottom of the iron base layer of the X-ray absorption pretreatment layer and is used to convert the heat energy generated after absorbing X-rays into electrical energy. The indirect conversion layer includes a piezoelectric conversion unit and a thermoelectric conversion unit. The piezoelectric conversion unit is used to convert the transient thermal deformation generated by X-ray irradiation of the iron base layer into electrical energy, and the thermoelectric conversion unit is used to generate supplementary power in the case of steady-state temperature difference. The power management module is electrically connected to the direct power generation layer and the indirect conversion layer, respectively. The power management module includes a dual-channel dynamic rectification circuit and a switching circuit.

2. The iron-based X-ray dual-mode energy recovery system according to claim 1, characterized in that: The depth-to-width ratio of the honeycomb cavity array is greater than 2:1 and less than 5:

1.

3. The iron-based X-ray dual-mode energy recovery system according to claim 1, characterized in that: The titanium nitride transition layer and the cadmium sulfide electron transition layer are sequentially deposited on the inner wall of the honeycomb cavity array by magnetron sputtering, and the cadmium telluride crystal layer is deposited on the cadmium sulfide electron transition layer by closed-space sublimation.

4. The iron-based X-ray dual-mode energy recovery system according to claim 1, characterized in that: The piezoelectric conversion unit consists of two sets of lead zirconate titanate ceramic sheets arranged in a row. One end of each set of lead zirconate titanate ceramic sheets is fixed to an anchor point on the iron substrate by a ceramic support, and the other end is coupled to the iron substrate by thermally conductive silicone. The two sets of lead zirconate titanate ceramic sheets are arranged orthogonally at a 45-degree angle, and the thermoelectric conversion unit is located between the piezoelectric conversion units.

5. The iron-based X-ray dual-mode energy recovery system according to claim 1, characterized in that: The dual-channel dynamic rectifier circuit includes a synchronous rectifier circuit and a voltage doubler rectifier circuit. The synchronous rectifier circuit is used to reduce rectification conduction losses and improve energy harvesting efficiency, while the voltage doubler rectifier circuit is used to increase the AC pulse voltage output by the piezoelectric conversion unit.

6. The iron-based X-ray dual-mode energy recovery system according to claim 1, characterized in that: The switching circuit is electrically connected to the photovoltaic channel, the piezoelectric channel, and the energy storage capacitor, respectively.

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