CN108982476B - Resistive photocathode for gas photoelectric detector, preparation method and test method - Google Patents
Resistive photocathode for gas photoelectric detector, preparation method and test method Download PDFInfo
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Abstract
The present disclosure provides a resistive photocathode for a gas photodetector, a method for manufacturing the same, and a method for testing the same, the resistive photocathode for a gas photodetector including: and a DLC film formed on the upper surface of the base layer. According to the resistive photocathode for the gas photoelectric detector, the preparation method and the test method, the DLC film is used for preparing the resistive photocathode material, the DLC film is deposited on the substrate layer by adopting a magnetron sputtering method, so that the DLC can be used as a transmission type photocathode material of the gas detector on one hand and can be also suitable for the application of the resistive electrode material of the gas detector on the other hand, and the DLC film with high quantum efficiency, proper resistivity, good thickness uniformity and strong bonding force can be obtained on the substrate layer by optimizing and improving the process parameters for preparing the DLC.
Description
Technical Field
The disclosure relates to the technical field of microstructure gas detectors, and particularly relates to a resistive photocathode for a gas photoelectric detector, a preparation method and a test method.
Background
The photocathode is used as a core component of a gas photoelectric detector and can convert Cerenkov light generated when high-energy incident particles pass through a medium into photoelectrons through an external photoelectric effect. The photoelectrons are further amplified in an avalanche mode in the gas detector, and signals are induced on the readout board, so that light detection is achieved.
At present, the prior art is used on a gas photoelectric detectorThe mainstream photocathode material is CsI. The CsI photocathode has relatively high Quantum Efficiency (QE-Quantum Efficiency) and a simpler preparation method (thermal evaporation method), and is widely applied to gas detectors for photoelectric detection, such as: the CsI transmission type photocathode in the Picosecond Micromega detector, wherein the radiator for generating Cerenkov light is MgF with the thickness of 3mm2When the crystal is manufactured by a transmission type photocathode, MgF is needed firstly2The crystal is coated with a layer of Cr with a thickness of about 3.3nm to be used as an electrode of a detector, and then CsI with a thickness of about 18nm is deposited on the Cr to be used as a photocathode.
Another common photocathode material is a metal photocathode, which has good stability and strong radiation resistance, but the quantum efficiency of photoelectric conversion is very low, so most of the metal photocathodes are used in experiments with a very large number of incident photons, such as: chromium or aluminum transmission type photocathode in Picosecond Micromegas detector, wherein the radiator for generating Cerenkov light is MgF2Crystals of MgF2A layer of chromium or aluminum is evaporated on the crystal and is simultaneously used as a detector electrode and a photocathode.
However, in carrying out the present disclosure, the inventors of the present application found that the CsI-based transmissive photocathode is susceptible to deliquescence upon contact with water vapor in the air during transportation and installation, resulting in a low CsI quantum efficiency. Under extreme circumstances, the crystal structure is even completely destroyed, and the function of photoelectric conversion is lost. Therefore, the storage environment of CsI is so strict that it is generally kept under vacuum, so that the storage cost is high and the operation is very inconvenient. Secondly, CsI has weak radiation resistance, is easy to damage by ion bombardment and ages very fast in high counting rate application. The metal photocathode has two main disadvantages, the first is that the quantum efficiency is low, so that MgF with larger thickness is required to be used2And (4) crystals. The use of a crystal with a large thickness not only causes a great increase in cost, but also causes a large diffusion range of cerenkov light, and in some applications requiring position measurement, the position resolution capability of the detector is deteriorated. The second is that the metal photocathode is a good conductor,when the metal photocathode is applied as an electrode in a gas detector, the metal photocathode does not play any role in inhibiting the sparking discharge of the detector, and further limits the application range of the metal photocathode. Therefore, the further development and application of the gas photoelectric detector in the field of nuclear and particle physics experiments are limited by the problems of the current mainstream photocathode material when being used in combination with the gas detector.
BRIEF SUMMARY OF THE PRESENT DISCLOSURE
Technical problem to be solved
Based on the technical problems, the disclosure provides a resistive photocathode for a gas photoelectric detector, a preparation method and a test method, so as to solve the technical problems that in the prior art, a CSI photocathode material is difficult to store and easy to age, a metal photocathode material is low in quantum efficiency, and does not play any inhibiting role in ignition and discharge of the detector.
(II) technical scheme
According to an aspect of the present disclosure, there is provided a resistive photocathode for a gas photodetector, comprising: a base layer; and a DLC film formed on the upper surface of the base layer.
In some embodiments of the present disclosure, wherein the substrate layer is MgF2And (5) crystallizing the wafer.
According to another aspect of the present disclosure, there is also provided a method of manufacturing a resistive photocathode of a gas photodetector, using a magnetron sputtering apparatus, including: step A: clamping the substrate layer, and exposing the upper surface of the substrate layer to a magnetron sputtering vacuum chamber; and B: bombarding and etching the upper surface of the substrate layer; and C: and sputtering and depositing the DLC film on the upper surface of the substrate layer.
In some embodiments of the present disclosure, further comprising step 1: and carrying out sputtering cleaning on the surface of the high-purity graphite target of the magnetron sputtering equipment.
In some embodiments of the disclosure, wherein: in the step A, wrapping the back and the side of the substrate layer by using aluminum foil, and putting the substrate layer into a tray; the bottom surface and the side surface of the base layer are embedded on the bottom surface and the inner surface of the tray.
In some embodiments of the present disclosure, the purity of the high purity graphite target is not less than 99.99%.
In some embodiments of the present disclosure, in step C: the current of the high-purity graphite target material is 1A, and the bias voltage is set to be 30V.
There is also provided, in accordance with another aspect of the present disclosure, a method for testing a resistive photocathode for a gas photodetector, comprising: step 10: the area resistivity of the resistive photocathode for a gas photodetector provided by the present disclosure was tested using a multimeter.
In some embodiments of the present disclosure, further comprising step 20: the resistive photocathode for a gas photodetector provided by the present disclosure was performance tested using a laser with a wavelength of 213 nanometers.
In some embodiments of the present disclosure, further comprising step 30: under the beam area environment of a large-scale hadron collider LHC, the performance of the resistive photocathode for the gas photoelectric detector provided by the disclosure is tested by using a Muon beam.
(III) advantageous effects
According to the technical scheme, the resistive photocathode for the gas photoelectric detector, the preparation method and the test method have one or part of the following beneficial effects:
(1) the resistive photocathode for the gas photoelectric detector can be simultaneously used as a photocathode material and a resistive electrode material to be applied to the gas detector, and compared with a pure metal photocathode, a DLC (Diamond like Carbon) resistive photocathode has higher photoelectric conversion efficiency as a photoelectric conversion material on one hand, and can be simultaneously applied to the resistive electrode material of the gas detector, so that the sparking discharge of the detector is effectively inhibited, the service life of the detector is prolonged, and the long-time working stability of the detector is improved;
(2) the resistance photocathode for the gas photoelectric detector is stable and reliable, and has strong anti-radiation and anti-aging capabilities, compared with a CsI photocathode, the DLC resistance photocathode has good binding force and stable and reliable performance on the one hand, and can be stored and operated in an atmospheric environment;
(3) the preparation method of the resistive photocathode for the gas photoelectric detector is simple and controllable, and the DLC film prepared by the magnetron sputtering method can be flexibly controlled in thickness and resistance by adjusting process parameters.
Drawings
Fig. 1 is a schematic structural diagram of a resistive photocathode for a gas photodetector according to an embodiment of the present disclosure.
Fig. 2 is a schematic flow chart of a method for manufacturing a resistive photocathode for a gas photodetector according to an embodiment of the present disclosure.
Fig. 3 is a schematic structural diagram of a device for preparing a resistive photocathode for a gas photodetector according to an embodiment of the present disclosure.
Fig. 4 is a schematic view of the structure of a tray in the manufacturing apparatus shown in fig. 3.
Fig. 5 is a schematic diagram of performance testing of a resistive photocathode for a gas photodetector provided by an embodiment of the present disclosure in a laboratory environment.
Fig. 6 is a schematic diagram of a performance test of a resistive photocathode for a gas photodetector provided in an embodiment of the present disclosure in a beam environment.
[ description of main reference numerals in the drawings ] of the embodiments of the present disclosure
10-a base layer;
20-DLC film.
Detailed Description
The resistive photocathode for the gas photoelectric detector, the preparation method and the test method provided by the embodiment of the disclosure use the diamond-like carbon-based film to prepare a resistive photocathode material with strong radiation resistance and aging resistance, and the DLC film is deposited on the substrate layer by adopting a magnetron sputtering method, so that the DLC can be used as a transmission-type photocathode material of the gas detector on one hand and can be applied to a resistive electrode material of the gas detector on the other hand.
For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.
According to one aspect of the present disclosure, as shown in fig. 1, there is provided a resistive photocathode for a gas photodetector, comprising: a base layer 10; the DLC film 20 is formed on the upper surface of the substrate layer 10, the resistive photocathode for the gas photoelectric detector provided by the embodiment of the disclosure can be simultaneously used as a photocathode material and a resistive electrode material to be applied to the gas detector, and compared with a pure metal photocathode, the DLC film 20 has higher photoelectric conversion efficiency as a photoelectric conversion material and can be applied to a resistive electrode material of the gas detector, so that the sparking discharge of the detector is effectively inhibited, the service life of the detector is prolonged, and the long-term working stability is improved; meanwhile, the resistive photocathode for the gas photoelectric detector provided by the embodiment of the disclosure is stable and reliable, and has strong anti-irradiation and anti-aging capabilities, and compared with the CsI photocathode, the DLC resistive photocathode has good bonding force and stable and reliable performance, and can be stored and operated in an atmospheric environment.
In some embodiments of the present disclosure, wherein the substrate layer is MgF2The thickness of the crystal wafer is between 2mm and 4mm, the diameter of the crystal wafer is between 24.6mm and 26.2mm, and the substrate material can be used as a Cerenkov radiator of a gas photodetector.
In some embodiments of the present disclosure, the DLC film 20 has a thickness between 10nm and 50nm, and needs to have good thickness uniformity.
In some embodiments of the present disclosure, the sheet resistance value of the DLC film 20 is between 10M Ω/□ and 100M Ω/□.
According to another aspect of the present disclosure, as shown in fig. 2 to 4, there is also provided a method for preparing a resistive photocathode of a gas photodetector, using a magnetron sputtering apparatus, including: step A: clamping the substrate layer 10 to expose the upper surface of the substrate layer in a magnetron sputtering vacuum chamber; and B: in order to improve the bonding force of the resistive photocathode, the upper surface of the substrate layer 10 is bombarded and etched before DLC is deposited, and the cavity is vacuumized to 3 x 10-5Turning on a pulse direct current power supply below Torr, applying a bias voltage between 100V and 400V on a substrate to be plated, introducing high-purity argon gas with the flow rate between 15Sccm and 20Sccm and keeping the gas pressure between 5 x 10-3Torr to 5X 10-4Torr, carrying out plasma bombardment and etching on the surface of the base material for 30 seconds; and C: sputtering and depositing DLC film 20 on the upper surface of the base layer 10 while maintaining the pressure inside the vacuum chamber at 5X 10-3Torr to 5X 10-4And setting the substrate bias voltage to be 30V, the graphite target current to be 1A, the rotating speed of a sample rotating frame to be 10 r/min, the sputtering deposition time to be 5min to 40min, and finally obtaining the DLC film 20 on the surface of the substrate material.
The magnetron sputtering apparatus used for preparing the resistive photocathode of the gas photodetector provided by the embodiment of the present disclosure, as shown in fig. 3, includes a power supply system, a vacuum chamber, a vacuum system, and a cooling system, where the vacuum chamber includes 2 high-purity graphite targets equipped with a weak magnetic field.
In some embodiments of the present disclosure, the method for preparing a resistive photocathode for a gas photodetector further includes, before step a, step 1: the method comprises the following steps of performing sputtering cleaning on the surface of a high-purity graphite target of magnetron sputtering equipment: starting a vacuum system, vacuumizing the vacuum chamber until the vacuum degree is reduced to 10-1When the temperature is below Torr, the molecular pump is automatically turned on, and the vacuum is continuously pumped until the vacuum degree is lower than 3X 10-5And opening circulating cooling water and a medium-frequency direct-current power supply when the graphite target is subjected to Torr, setting the bias voltage between 70V and 150V, setting the current of the graphite target between 1.5A and 4A, introducing high-purity argon with the flow rate between 15sccm and 20sccm into a vacuum chamber, and carrying out sputtering cleaning on the surface of the high-purity graphite target for 30-90 minutes.
In some embodiments of the disclosure, wherein: in the step A, wrapping the back and the side of the substrate layer 10 by using aluminum foil, and putting the whole substrate layer into a well-arranged tray; as shown in fig. 4, the bottom and side surfaces of the substrate layer 10 are embedded in the bottom and inner surfaces of the tray to prevent the side and back surfaces of the substrate material from being coated with DLC, the tray is mounted and fixed on a sample turret and placed in a vacuum chamber, and the position of the turret is adjusted to place the substrate material in the middle of a high purity graphite target with a target pitch of 14cm to 17 cm.
In some embodiments of the present disclosure, the purity of the high purity graphite target is not less than 99.99%.
In this disclosure, step C: the current of the high-purity graphite target is 1A, the bias voltage is set to be 30V, the sputtering deposition time is between 5 minutes and 40 minutes, in the process of preparing the DLC film 20 by using a magnetron sputtering method, the target current can affect the deposition rate of the DLC film 20, the target current is too large, carbon atom clusters sputtered out are large, the uniformity of the DLC film 20 is poor, the target current is too small, DLC is difficult to deposit on a substrate material, in order to obtain proper DLC film 20 resistance and high quantum efficiency, the thickness of DLC needs to be controlled to be between 10 nanometers and 50 nanometers, the thickness uniformity is good, and therefore the target current needs to be optimized.
According to yet another aspect of the present disclosure, there is also provided a method of testing a resistive photocathode for a gas photodetector, comprising: step 10: the method comprises the steps of testing the surface resistivity of a resistive photocathode for the gas photoelectric detector provided by the embodiment of the disclosure by using a multimeter; step 20: in a laboratory environment, a performance test is performed on the resistive photocathode for the gas photoelectric detector provided by the embodiment of the disclosure by using laser with the wavelength of 213 nanometers; and/or step 30: under the beam area environment of a large-scale hadron collider LHC, the performance of the resistive photocathode for the gas photoelectric detector provided by the embodiment of the disclosure is tested by using a Muon beam.
In some embodiments of the present disclosure, the DLC resistive photocathode provided in the embodiments of the present disclosure and a micro grid gas detector (MicroMegas) are combined together to assemble a gas photodetector, and the resistive photocathode provided in the embodiments of the present disclosure for a gas photodetector is used as a photocathode of a MicroMegas detector to implement photoelectric conversion on one hand, and is used as a resistive electrode of a detector to suppress sparking discharge of the detector on the other hand; in a laboratory environment, as shown in fig. 5, a performance test is performed on the resistive photocathode for a gas photodetector provided in the embodiment of the present disclosure by using a laser with a wavelength of 213 nm, when the laser is incident on the DLC film 20, photoelectrons are excited, and the photoelectrons undergo avalanche amplification inside the gas detector, and finally a signal is induced on a detector readout strip and collected by an oscilloscope; or as shown in fig. 6, a Muon beam can be used to perform a performance test on the resistive photocathode for a gas photodetector provided in the embodiment of the present disclosure in a beam area environment of a large hadron collider LHC, when a high-energy Muon (150GeV) particle passes through a magnesium fluoride crystal, cerenkov light is generated to be incident on the DLC film 20 to excite photoelectrons, the photoelectrons are avalanche amplified inside the gas detector, and finally, a signal is induced on a detector readout strip and is acquired by an oscilloscope, and two scintillator detectors are respectively arranged in front of and behind the gas photodetector as trigger detectors.
The effectiveness of the resistive photocathode for the gas photodetector, the preparation method and the test method provided by the embodiment of the disclosure is verified through a specific embodiment as follows:
in the present example, a Teer 650 magnetron sputtering device was used for MgF2Preparation of DLC film on Crystal
Step 1, pre-treating a substrate sample (base layer 10), comprising the following steps: MgF with the thickness of 3mm and the diameter of 25.4mm is selected2The crystal wafer is used as a base material, and the base material is wiped and cleaned by using dust-free cloth;
step 2, high purityThe method for carrying out sputtering cleaning on the surface of the graphite target comprises the following steps: pumping the vacuum degree of the cavity to 2 x 10-5And (3) opening a circulating cooling system, starting a medium-frequency direct-current power supply system, introducing high-purity argon with the flow of 16sccm, setting the bias voltage to be 100V, setting the current of the high-purity graphite target to be 3.5A, and carrying out sputtering cleaning on the surface of the high-purity graphite target for 1 hour.
And 3, fixing the base material, comprising the following steps: wrapping the back and the side of a substrate material by using aluminum foil, integrally putting the substrate material on a tray, integrally fixing and tightly attaching the tray on a stainless steel rotating frame by using screws, installing the rotating frame on a rotating shaft in a vacuum chamber, and adjusting the position of a substrate to ensure that the height of the substrate is positioned in the middle of a high-purity graphite target material, wherein the distance between a target surface and the substrate is 15 cm;
and 4, carrying out plasma bombardment and etching on the surface of the base material, wherein the method comprises the following steps: opening the mechanical pump to pre-pump the chamber until the vacuum degree of the chamber is about 10-1When the pressure is Torr, the molecular pump is automatically opened to continue vacuum pumping, and when the vacuum degree is up to 10- 6When the Torr is in an order of magnitude, a circulating cooling system and a medium-frequency direct-current power supply system are opened, a bias voltage of 300V is applied on a base material to be plated, high-purity argon with the flow rate of 16Sccm is introduced, and the air pressure is kept at 8 x 10-4Torr, carrying out plasma bombardment and etching on the surface of the base material for 30 seconds;
step 5, further MgF2The preparation of the DLC resistive photocathode on the surface of the crystal comprises the following steps: maintaining the internal pressure of the vacuum chamber at 8 × 10-4Adjusting the bias voltage of the base material to 30V, setting the current of the high-purity graphite target to 1A, adjusting the rotating speed of a base material rotating stand to 10 revolutions per minute, and performing sputtering deposition for 5 minutes to obtain a photocathode on a quartz crystal;
step 6, preparing DLC films 20 with different thicknesses, comprising the following steps: under the condition of ensuring that the conditions of the steps 1, 2, 3 and 4 are not changed, only the MgF in the step 5 is changed2The time for sputtering and depositing DLC on the crystal is respectively set as 10min, 20min and 40min, and MgF is coated2DLC resistive photocathodes with different thicknesses are obtained on the crystal;
and 7, testing the DLC film, which comprises the following steps:
step 71: the surface resistance value of the DLC resistive photocathode material is measured by using a multimeter, the obtained DLC resistive photocathode material with different thicknesses has the surface resistance value of 10 MOmega/□ -100 MOmega/□, the longer the deposition time is, the smaller the resistance value of the DLC surface resistor is, and the DLC film material in the resistance value range can be suitable for the resistive electrode material of the microstructure gas detector, so that the ignition and discharge of the detector are inhibited. The DLC resistive photocathode material with the deposition time of 20min is tested to have the DLC film thickness of about 20 nanometers and good bonding force.
Step 72: the DLC film 20 is tested in a laboratory environment, and MgF coated with the DLC film 202The crystal sample is made into an incidence window of a micro-grid gas detector (MicroMegas), and is also used as a photocathode and a resistive electrode of the detector at the same time, and high voltage is applied to the detector to enable the detector to be in a normal working mode; and (3) opening the laser, dividing the laser into two paths by using a spectrometer, wherein one path of the laser is incident on an MCP (multi-channel plate) to be used as a trigger signal, the other path of the laser is incident on the DLC film 20 to convert the laser into photoelectrons, and a signal of a gas detector is adopted on an oscilloscope to test the performance of the DLC photocathode. And under the same condition, testing the DLC photocathode with the deposition time of 5min, 10min, 20min and 40min respectively, and the result shows that the DLC photocathode with the deposition time of 10min has relatively high quantum efficiency for the laser with the wavelength of 213 nanometers.
Step 73: testing the DLC film in a beam environment, mounting a detector on an experimental platform of a beam area, respectively placing two MCP-PMTs at the front and the rear of the detector as trigger signals, applying high voltage to the detector to enable the detector to be in a working mode, wherein beam particles are 150GeV Muon condition that Muon passes through MgF2When the crystal is in a crystal state, Cerenkov light is generated and is transmitted to the DLC film to generate photoelectrons, the photoelectrons are subjected to avalanche amplification in a sensitive area of a detector, a voltage signal is induced on a reading strip, the signal is finally collected by an oscilloscope, and a test result shows that the DLC photocathode with the deposition time of 10min is better than the DLC photocathode with the deposition time of 20min under the same condition and accords with a test result in a laboratory,MgF thickness of 3mm for a single Muon particle2The DLC resistive photocathode with the deposition time of 10min can generate 2.4 photoelectrons, and for a pure metal aluminum photocathode, a single Muon particle passes through MgF with the thickness of 5mm2The generated Cerenkov light can generate 2.2 photoelectrons, so that the photoelectric conversion effect of the DLC film 20 is obviously better than that of a pure metal aluminum photocathode.
In addition, in the long-time test of the photocathode in the beam area, the DLC film 20 can work stably for a long time, the invisible photocathode has an aging phenomenon, the normal working time of the CsI photocathode is about one day, and the CsI crystal structure is damaged by the bombardment of incident particles, so that the stability and the anti-irradiation performance of the DLC resistive photocathode are obviously superior to those of the CsI photocathode.
From the above description, those skilled in the art should have clear understanding of the resistive photocathode for gas photodetectors, the preparation method, and the test method provided by the present disclosure.
In summary, the resistive photocathode for the gas photoelectric detector, the preparation method and the test method provided by the embodiment of the disclosure use the diamond-like carbon-based film to prepare a resistive photocathode material with strong anti-radiation and anti-aging capabilities, a magnetron sputtering method is adopted to deposit a DLC film on the substrate layer, so that the DLC can be used as a transmission type photocathode material of the gas detector on one hand and can be also suitable for the application of a resistance electrode material of the gas detector on the other hand, and through optimizing and improving the process parameters of DLC preparation, the DLC film with high quantum efficiency, proper resistivity, good thickness uniformity and strong bonding force can be obtained on the basal layer, because DLC has the characteristics of high mechanical strength and high physical and chemical stability, DLC is very suitable to be used as a photoelectric conversion material in the current physical experiments of high-brightness nuclei and particles.
It should also be noted that directional terms, such as "upper", "lower", "front", "rear", "left", "right", and the like, used in the embodiments are only directions referring to the drawings, and are not intended to limit the scope of the present disclosure. Throughout the drawings, like elements are represented by like or similar reference numerals. Conventional structures or constructions will be omitted when they may obscure the understanding of the present disclosure.
And the shapes and sizes of the respective components in the drawings do not reflect actual sizes and proportions, but merely illustrate the contents of the embodiments of the present disclosure. Furthermore, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.
Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various disclosed aspects. However, the disclosed method should not be interpreted as reflecting an intention that: that is, the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, disclosed aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this disclosure.
The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present disclosure in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present disclosure and are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.
Claims (9)
1. A resistive photocathode for a gas photodetector, comprising:
a base layer; the basal layer is MgF2A crystal; the thickness of the substrate layer is between 2mm and 4 mm; and
a DLC film formed on the upper surface of the base layer, the DLC film serving as a transmissive photocathode material; the thickness of the DLC film is between 10nm and 50 nm; the surface resistance value of the DLC film is between 10M omega/port and 100M omega/port.
2. A method of making a resistive photocathode for a gas photodetector as claimed in claim 1, using a magnetron sputtering apparatus, comprising:
step A: clamping the substrate layer, and exposing the upper surface of the substrate layer to a magnetron sputtering vacuum chamber;
and B: bombarding and etching the upper surface of the substrate layer;
and C: and sputtering and depositing the DLC film on the upper surface of the substrate layer.
3. The method of preparing a resistive photocathode for a gas photodetector of claim 2, further comprising the steps of 1: and carrying out sputtering cleaning on the surface of the high-purity graphite target of the magnetron sputtering equipment.
4. The method of fabricating a resistive photocathode for a gas photodetector of claim 2, wherein:
in the step A, wrapping the back and the side of the substrate layer by using aluminum foil, and putting the substrate layer into a tray;
the bottom surface and the side surface of the base layer are embedded on the bottom surface and the inner surface of the tray.
5. The method for preparing a resistive photocathode of a gas photodetector of claim 3, wherein the purity of the high-purity graphite target material is not less than 99.99%.
6. The method according to claim 2, wherein in the step C: the current of the high-purity graphite target material is 1A, and the bias voltage is set to be 30V.
7. A method of testing a resistive photocathode for a gas photodetector, comprising:
step 10: the area resistivity of the resistive photocathode for a gas photodetector of claim 1 was tested using a multimeter.
8. A method of testing a resistive photocathode for a gas photodetector according to claim 7, further comprising: step 20: a performance test of the resistive photocathode for a gas photodetector of claim 1 was performed using a laser with a wavelength of 213 nm.
9. A method of testing a resistive photocathode for a gas photodetector according to claim 7, further comprising: step 30: the performance test of the resistive photocathode for the gas photodetector of claim 1 is performed by using a Muon beam in a beam area environment of a large hadron collider LHC.
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