阅读说明：本技术 脉冲x射线辐射场内的光子数与电子数之比测量装置及方法 (Device and method for measuring the ratio of the number of photons to the number of electrons in a pulsed X-ray radiation field ) 是由 谢彦召 吕泽琦 陈晓宇 苟明岳 于 2021-08-05 设计创作，主要内容包括：本发明公开了一种脉冲X射线辐射场内的光子数与电子数之比测量装置及方法,属于脉冲功率技术测量领域,具有吸收辐射场内的电子和测量辐射场内光子数与电子数之比的功能,包括二极管、真空实验腔、实验腔后端盖板及剂量测量系统和电流测量系统。二极管与真空实验腔连接为一体,实验腔后端盖板密封连接真空实验腔,剂量测量系统测量脉冲X射线的剂量分布；电流测量系统测量辐射场内电子；由剂量和能谱计算得到光子数,电流计算得到电子数,获得光子数与电子数之比。本发明在吸收辐射场中电子的同时对光子影响较小,有效减小了脉冲X射线效应试验中电子的干扰,建立了辐射场内的光子数与电子数之比测量系统,有助于后续试验中对脉冲X射线效应进行更准确的分析。(The invention discloses a device and a method for measuring the ratio of photon number to electron number in a pulse X-ray radiation field, which belong to the technical field of pulse power measurement, have the functions of absorbing electrons in the radiation field and measuring the ratio of the photon number to the electron number in the radiation field, and comprise a diode, a vacuum experimental cavity, an experimental cavity rear end cover plate, a dose measuring system and a current measuring system. The diode is connected with the vacuum experimental cavity into a whole, a cover plate at the rear end of the experimental cavity is connected with the vacuum experimental cavity in a sealing manner, and the dose measurement system measures the dose distribution of the pulse X-ray; the current measuring system measures electrons in the radiation field; and calculating the dose and the energy spectrum to obtain the photon number, calculating the current to obtain the electron number, and obtaining the ratio of the photon number to the electron number. The invention has small influence on photons while absorbing electrons in a radiation field, effectively reduces the interference of electrons in a pulse X-ray effect test, establishes a system for measuring the ratio of the number of photons to the number of electrons in the radiation field and is beneficial to more accurately analyzing the pulse X-ray effect in a subsequent test.)

1. The device for measuring the ratio of the photon number to the electron number in a pulse X-ray radiation field is characterized by comprising a vacuum experiment cavity (8) and a diode (1) which is integrally designed with the vacuum experiment cavity (8), wherein the diode (1) is arranged at one end of the vacuum experiment cavity (8), the other end of the vacuum experiment cavity (8) is provided with an experiment cavity rear end cover plate (9) for sealing, a dose measuring system and a Rogowski coil (16) of a current measuring system are also arranged in the vacuum experiment cavity (8), the dose measuring system is embedded in the inner side of the Rogowski coil (16) of the current measuring system, and the Rogowski coil (16) and the dose measuring system are coaxial and are arranged perpendicular to the direction of the pulse X-ray;

the dose measuring system comprises a dose plate support bottom plate (10), a cover plate (11), a dose plate (13) and a supporting base (14); the end face of the dose sheet (13) faces the incidence direction of the pulse X-ray, the dose sheet is placed on a dose sheet support bottom plate (10) and fixed by a cover plate (11), a support base (14) is embedded in a Rogowski coil (16), and the dose sheet support bottom plate (10) is fixed on the support base (14).

2. The device for measuring the ratio of the number of photons to the number of electrons in a pulsed X-ray radiation field according to claim 1, characterized in that the diode (1) comprises a vacuum-insulating diaphragm (2), a cathode support (3), a diode cathode (4) and a diode anode composite target and fixing structure (15); wherein, the cathode support (3) is connected with the vacuum insulation clapboard (2), the anode conversion target and the fixed structure (15) are connected with the vacuum experiment cavity (8), the diode cathode (4) is arranged on the cathode support (3), and high-voltage pulse is input from the diode cathode (4).

3. The device for measuring the ratio of the number of photons to the number of electrons in a pulsed X-ray radiation field according to claim 2, characterized in that said diode anode composite target and holding structure (15) comprises a metal conversion target (5), a polyethylene film clamping ring (6) and a metal conversion target holding structure (7); the metal conversion target fixing structure (7) compresses and flattens the metal conversion target (5), and the polyethylene film is fixed on the outer side of the metal conversion target (5) by the polyethylene film pressing ring (6).

4. Device for measuring the ratio of the number of photons to the number of electrons in a pulsed X-ray radiation field according to claim 1, characterized in that the dose disk (13) is a lithium fluoride pyroelectric detector with an irradiation zone of 4.5mm diameter and 0.8mm thickness, measured in the range of 10 μ Gy to 10 Gy.

5. The device for measuring the ratio of the number of photons to the number of electrons in a pulsed X-ray radiation field according to claim 1, wherein the bottom plate (10) of the dose plate holder is provided with a plurality of grooves for receiving the dose plates (13), the plurality of grooves are arranged on the bottom plate (10) of the dose plate holder in two mutually perpendicular radial directions, and the adjacent grooves are spaced by 1 cm.

6. Device for measuring the ratio of the number of photons to the number of electrons in a pulsed X-ray radiation field according to claim 5, characterised in that the rogowski coil (16) is a differential rogowski coil, the rogowski coil (16) being provided with a metallic shielding housing, the measurement signal being output via a BNC cable head on the metallic shielding housing, the metallic shielding housing being insulated from the X-ray system housing and not being grounded.

7. The device for measuring the ratio of the number of photons to the number of electrons in a pulsed X-ray radiation field according to claim 1, characterized in that the current measuring system further comprises a data transmission unit and a data acquisition unit, which are arranged outside the vacuum laboratory chamber (8), the measurement results of the rogowski coil (16) being transmitted to the data acquisition unit by means of the data transmission unit.

8. Method for measurement using a device for measuring the ratio of the number of photons to the number of electrons in a pulsed X-ray radiation field according to any of claims 1 to 7, comprising the steps of:

the method comprises the following steps: high-voltage pulses are loaded to the diode (1), and after being converted into pulse X-rays, the pulse X-rays enter the vacuum experiment cavity (8), a dose measuring system in the vacuum experiment cavity (8) measures the pulse X-ray dose distribution to obtain the total dose, and the total dose and the energy spectrum distribution of the pulse X-rays are calculated to obtain the total photon number;

step two: measuring current by using a Rogowski coil (16), and obtaining the total number of electrons in the radiation field by using the current;

step three: and calculating to obtain the ratio of the total number of photons to the total number of electrons.

9. The method for measuring by a device for measuring a ratio of photon count to electron count in a pulsed X-ray radiation field according to claim 8, wherein in the first step, the area represented by the measured value of each dose slice (13) increases with the radius, the total dose of the measured surface is determined by area weighting, the dose of the pulsed X-ray is the absorbed dose, the photon fluence, i.e. the number of photons per unit area, is determined by the conversion relationship between the absorbed dose and the photon fluence of the pulsed X-ray of different energy bands, and the total photon count is obtained by multiplying the irradiation area.

10. The method for measuring a ratio of photon count to electron count in a pulsed X-ray radiation field according to claim 8, wherein in the second step, the total number of electrons is calculated by measuring a current by a rogowski coil (16) in a current measuring system, and the measured current is integrated over the pulsed X-ray generation time.

Technical Field

The invention belongs to the technical field of pulse power measurement, and relates to an absorption structure for electrons in a pulse X-ray radiation field and a device and a method for measuring the ratio of the number of photons to the number of electrons in the radiation field.

Background

Pulsed X-rays are typically generated by a vacuum diode, high voltage pulses are applied to the diode, electrons are emitted from the cathode, accelerated by an electric field in the diode gap, and bombard the anode conversion target. The speed of the electrons is rapidly reduced when the electrons approach the atomic nucleus of the target material, bremsstrahlung occurs to form pulse X-rays, and a small amount of electrons penetrate the anode target. The larger the atomic number of the anode target material, the higher the conversion efficiency of the target and the higher the intensity of the generated pulsed X-rays. Therefore, a metal material with a high atomic number is generally selected as the conversion target. In the prior art, when researches such as system electromagnetic pulse effect, biological effect and the like are carried out, effectors can be influenced by the combined action of photons and electrons, and the influence of pulse X-rays is difficult to distinguish. Therefore, there is a need for an electron absorbing structure in a radiation field that reduces electrons in the radiation field and has as little effect on photons as possible for subsequent pulsed X-ray effect tests to be performed.

In order to evaluate the ratio of photons to electrons in a pulsed X-ray radiation field and to distinguish the effect of electrons and photons on an effector, the number of photons and the number of electrons need to be measured, which provides support for more accurate analysis of the pulsed X-ray effect in subsequent experiments.

Disclosure of Invention

In order to overcome the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a device and a method for measuring the ratio of the number of photons to the number of electrons in a pulsed X-ray radiation field, which realize the functions of absorbing electrons in the radiation field and measuring the number of photons and the number of electrons in the radiation field, evaluate the ratio of photons to electrons in the pulsed X-ray radiation field, measure the number of photons and the number of electrons, and further distinguish the influence of electrons and photons on effectors.

In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:

the device for measuring the ratio of the number of photons to the number of electrons in a pulse X-ray radiation field is characterized by comprising a vacuum experimental cavity and a diode which is integrally designed with the vacuum experimental cavity, wherein the diode is arranged at one end of the vacuum experimental cavity, the other end of the vacuum experimental cavity is provided with an experimental cavity rear end cover plate for sealing, a dose measuring system and a Rogowski coil of a current measuring system are also arranged in the vacuum experimental cavity, the dose measuring system is embedded in the Rogowski coil of the current measuring system, and the Rogowski coil and the dose measuring system are coaxial and are both arranged perpendicular to the direction of a pulse X-ray;

the dose measuring system comprises a dose sheet bracket bottom plate, a cover plate, a dose sheet and a supporting base; the end face of the dose sheet faces to the incident direction of the pulse X-ray, the dose sheet is placed on a dose sheet support bottom plate and fixed by a cover plate, a support base is embedded in the Rogowski coil, and the dose sheet support bottom plate is fixed on the support base.

Preferably, the diode comprises a vacuum insulation separator, a cathode support, a diode cathode and diode anode composite target and a fixed structure; the cathode support is connected with the vacuum insulation partition plate, the diode anode composite target and the fixed structure are connected with the vacuum experiment cavity, the diode cathode is arranged on the cathode support, and high-voltage pulses are input from the diode cathode.

Preferably, the diode anode composite target and fixing structure comprises a metal conversion target, a polyethylene film pressure ring and a metal conversion target fixing structure; the metal conversion target fixing structure compresses and flattens the metal conversion target, and the polyethylene film compression ring fixes the polyethylene film on the outer side of the metal conversion target.

Furthermore, the metal conversion target is made of a material with high atomic number, so that the conversion efficiency is improved.

Preferably, the dose sheet is a lithium fluoride thermoluminescent detector, the diameter of an irradiation area of the lithium fluoride thermoluminescent detector is 4.5mm, the thickness of the lithium fluoride thermoluminescent detector is 0.8mm, and the measurement range is 10 mu Gy-10 Gy.

Preferably, a plurality of grooves for placing the dosage pieces are formed in the dosage piece support bottom plate, the grooves are formed in the dosage piece support bottom plate along two mutually perpendicular radius directions, and the interval between every two adjacent grooves is 1 cm.

Preferably, the Rogowski coil is a differential Rogowski coil, the Rogowski coil is provided with a metal shielding shell, a measurement signal is output through a BNC cable head on the metal shielding shell, and the metal shielding shell is insulated from the X-ray system shell and is not grounded.

Preferably, the current measurement system further comprises a data transmission unit and a data acquisition unit, the data transmission unit and the data acquisition unit are arranged outside the vacuum experiment cavity, and the measurement result of the rogowski coil is transmitted to the data acquisition unit through the data transmission unit.

The invention also discloses a method for measuring by using the device for measuring the ratio of the number of photons to the number of electrons in the pulsed X-ray radiation field, which comprises the following steps:

the method comprises the following steps: loading high-voltage pulses to a diode, converting the high-voltage pulses into pulse X-rays, entering a vacuum experimental cavity, measuring by a dose measuring system in the vacuum experimental cavity to obtain pulse X-ray dose distribution, calculating to obtain total dose, and calculating to obtain total photon number according to the total dose and the energy spectrum distribution of the pulse X-rays;

step two: measuring current by using a Rogowski coil, and obtaining the total number of electrons in a radiation field by using the current;

step three: and calculating to obtain the ratio of the total number of photons to the total number of electrons.

Preferably, in the step one, the area represented by the measured value of each dose slice increases with the radius, the total dose of the measured surface is calculated through area weighting, the dose of the pulse X-ray refers to the absorbed dose, the photon fluence, i.e. the number of photons per unit area, is calculated according to the conversion relation between the absorbed dose and the photon fluence of the X-ray of different energy bands, and then the total photon number is obtained by multiplying the number by the irradiation area;

preferably, in the second step, the total number of electrons is calculated by measuring the current by a rogowski coil in a current measuring system, and the measured current is integrated within the generation time of the pulse X-ray.

Compared with the prior art, the invention has the following beneficial effects:

the invention discloses a device for measuring the ratio of photon number to electron number in a pulse X-ray radiation field, which integrates a diode and a vacuum experimental cavityDesigning, keeping the same vacuum degree, placing a Rogowski coil and a dose measuring system of a current measuring system in a vacuum experimental cavity, embedding the dose measuring system in the Rogowski coil of the current measuring system, coaxially placing the Rogowski coil and the dose measuring system of the current measuring system, measuring the dose and the current at the same position, obtaining the ratio of photon number to electron number, and reducing the error caused by external factors; the device for measuring the ratio of the number of photons to the number of electrons in the pulsed X-ray radiation field is simple to operate and convenient to use; can be used at an air pressure of not less than 10^-3And the device can be directly placed in an experiment cavity connected with a diode in a Pa vacuum environment, is convenient to use, and provides data support for development of subsequent effect experiments.

Further, the diode anode composite target and fixing structure comprises a metal conversion target, a polyethylene film pressure ring and a metal conversion target fixing structure; the electron absorption device and the metal conversion target are fixed together through the polyethylene film pressure ring and the metal conversion target fixing structure to form the composite target, no additional device is needed, the polyethylene film has small influence on X rays when absorbing electrons, and the beneficial effects of good absorption effect, simplicity in operation and the like are achieved.

Furthermore, the lithium fluoride thermoluminescent detector with the diameter of the irradiation area of 4.5mm, the thickness of 0.8mm and the measurement range of 10 mu Gy-10Gy is adopted as a dosage tablet, and the lithium fluoride thermoluminescent detector has small volume and convenient use.

Furthermore, a plurality of grooves are arranged on the bottom plate of the dose sheet support along two mutually perpendicular radius directions at intervals of 1cm for placing dose sheets, and the dose sheets are arranged in a radial mode, so that the intensity and uniformity of a radiation field can be obtained simultaneously.

Furthermore, the differential Rogowski coil adopted by the invention is provided with a metal shielding shell, is insulated from and not grounded with the shell of an X-ray system, overcomes the interference of a strong radiation field on small current measurement, and can accurately obtain the number of electrons in the radiation field by matching with a data acquisition and processing system.

The invention provides a method for measuring by using a device for measuring the ratio of photon number to electron number in a pulse X-ray radiation field, wherein the photon number is obtained by calculating the energy spectrum and the dose of the pulse X-ray; the electronic number is obtained by integrating the current measured by the Rogowski coil in the pulse X-ray generation time, and the current is the sensitivity obtained by dividing the voltage signal of the oscilloscope by calibration; and meanwhile, the ratio of the photon number to the electron number is measured, so that the functions of absorbing electrons in a radiation field and measuring the photon number and the electron number of the radiation field are realized, the use is convenient and fast, and data support is provided for the development of subsequent effect experiments.

Drawings

FIG. 1 is a schematic diagram of a diode and a vacuum experimental chamber according to the present invention;

FIG. 2 is a schematic view of a dosimetry system of the invention;

FIG. 3 is a schematic view of a photon and electron count measurement layout according to the present invention;

FIG. 4 is a graph of the dose distribution over radius in a radiation field measured experimentally with the present invention.

Wherein: 1-a diode; 2-vacuum insulation partition board; 3-a cathode support; 4-diode cathode; 5-a metal conversion target; 6-polyethylene film compression rings; 7-a metal conversion target fixing structure; 8-vacuum experimental cavity; 9-a rear end cover plate of the experimental cavity; 10-dose plate holder baseplate; 11-a cover plate; 12-a set screw; 13-dose tablets; 14-a support base; 15-diode anode composite target and fixed structure; 16-rogowski coil.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention is described in further detail below with reference to the accompanying drawings:

as shown in FIG. 1, the diode 1 and the vacuum experimental chamber 8 of the preferred embodiment of the present invention are designed integrally, the same vacuum degree is maintained, the vacuum is sealed by the vacuum insulation partition plate 2, the system housing and the experimental chamber rear end cover plate 9, and the vacuum degree in the vacuum experimental chamber 8 is maintained at 10 during the experiment^-3Pa in order to ensure the isolation of the diode 1 and the generation of pulsed X-rays. The diode 1 mainly comprises a vacuum insulation clapboard 2, a cathode support 3, a diode cathode 4, a metal conversion target 5, a metal conversion target fixing structure 7, a polyethylene film pressure ring 6 and a polyethylene film, the metal conversion target fixing structure 7 compresses and flattens the metal conversion target 5, the polyethylene film pressing ring 6 fixes the polyethylene film on the outer side of the metal conversion target 5 to form a diode anode composite target and fixing structure 15, the cathode support 3 of the diode is connected with the vacuum insulation partition plate 2, the anode conversion target and fixing structure 15 of the diode is connected with the vacuum experiment cavity 8, the diode cathode 4 is arranged on the cathode support 3, the cathode support 3 is arranged between the anode conversion target and fixing structure 15 and the vacuum insulation partition plate 2, high-voltage pulse is input from the diode cathode 4, wherein the metal conversion target 5 generally selects a material with high atomic number, and the conversion efficiency is improved. The metal conversion target 5 selected in the embodiment is a tantalum film with the thickness of 20 microns, and the metal conversion target 5, a polyethylene film compression ring 6 and a metal conversion target fixing structure 7 jointly form a diode anode composite target and a diode anode fixing structure 15.

High voltage pulse is input from the cathode 4 of the diode, and the anode of the diode is grounded and connected with the system shell. The pulse is loaded between the cathode and the anode of the diode 1, under the action of a high-voltage pulse electric field, the cathode 4 of the diode emits electrons and is accelerated in the gap to bombard the metal conversion target 5, bremsstrahlung radiation is converted into X rays, part of the electrons can penetrate through the metal conversion target 5, and the polyethylene film absorbs the electrons behind the metal conversion target. A Rogowski coil 16 of a dose measuring system and a current measuring system is placed in the experiment cavity, and measuring results are led out through an interface on a shell of a system shell.

As shown in fig. 2, the dosimetry system of the invention comprises a dose plate holder bottom plate 10, a cover plate 11, a fixing screw 12 and a support base 14, wherein the end surface of a dose plate 13 faces the incident direction of a pulse X-ray, and is placed on the dose plate holder bottom plate 10 and fixed by the cover plate 11, the support base 14 is embedded in a rogowski coil 16, the dose plate holder bottom plate 10 is fixed on the support base 14, the dose plate holder bottom plate 10 is provided with grooves 1cm apart along two mutually perpendicular radial directions, the dose plate 13 is placed in the grooves, the diameter of each groove is 5mm, and the number of the grooves is 21, and the support base 14 supports and fixes the dose plate holder bottom plate 10; the support base 14 is made of nylon and is in a semicircular shape. The dose sheet 13 is a circular lithium fluoride thermoluminescent detector with the diameter of 4.5mm and the thickness of 0.8mm, the measurement range is 10 mu Gy-10Gy, the lithium fluoride thermoluminescent detector mainly comprises lithium fluoride LiF and comprises magnesium Mg, copper Cu and phosphorus P, and annealing treatment is carried out before use, so that the measurement accuracy is ensured. The dose pieces 13 are arranged in a radial shape, so that the maximum dose of a radiation field can be obtained, the distribution uniformity of X-rays can be obtained, and different numbers of dose pieces 13 can be arranged according to the requirement.

As shown in fig. 3, the electrons emitted from the diode cathode 4 enter the vacuum experimental chamber 8 through the metal transfer target 5 and the polyethylene film, the dose plate 13 and the dose plate holder base plate 10, the support base 14 are placed at the same position of the vacuum experimental chamber 8 as the rogowski coil 16, the dose plate 13 is arranged in the area surrounded by the rogowski coil 16, the dose and the current at the same position are measured, and the ratio of the number of photons to the number of electrons is obtained. Wherein the photon number is calculated from the energy spectrum and dose of the pulse X-ray, and the electron number is obtained by dividing the integral of the current measured by the rogowski coil 16 in the pulse X-ray generation time by the electron charge. The Rogowski coil 16 of the invention is wound on a circular nylon framework with a rectangular cross section and is made of a stainless steel shell in an electromagnetic shielding mode. Because the transmitted electron beam current is small and is easily interfered by electromagnetic radiation of a test environment to influence a measurement result, differential winding is used. In this embodiment, the rogowski coil 16 outputs a waveform by using a self-integration circuit structure, and the output voltage is in direct proportion to the current to be measured without an external integrator. Before use, the sensitivity of the Rogowski coil 16 is calibrated, a signal source generates a measured current, the measured current is connected with a 50-ohm matching resistor, the output current of the signal source is measured simultaneously by using a standard current loop and the Rogowski coil 16 to be calibrated, and the waveforms of the standard current loop and the Rogowski coil are compared to calibrate the sensitivity of the Rogowski coil. The current signal measured by the rogowski coil 16 is obtained by dividing the voltage signal acquired by the oscilloscope by the sensitivity.

Referring to fig. 1, 2 and 3, the device for measuring the ratio of the number of photons to the number of electrons in a pulsed X-ray radiation field comprises a diode anode composite target and fixed structure 15, a dose measuring system in a vacuum laboratory cavity 8 behind a diode 1 and a current measuring system for measuring the number of electrons; the diode anode composite target and fixing structure 15 is composed of a metal conversion target 5 with a high atomic number, a polyethylene film pressing ring 6 and a metal conversion target fixing structure 7, wherein the metal conversion target fixing structure 7 fixes the metal conversion target 5, and the polyethylene film pressing ring 6 fixes the polyethylene film on the outer side of the metal conversion target 5. Electrons generate bremsstrahlung through the metal conversion target 5 to generate pulse X rays, and the polyethylene film absorbs the transmitted electrons after the metal conversion target 5; the dose measuring system comprises a dose plate support base plate 10, a cover plate 11, a dose plate 13 and a support base 14; the end face of the dose plate 13 faces the incident direction of the pulse X-ray, and is placed on the dose plate support base plate 10 and fixed by the cover plate 11, and the dose plate support base plate 10 is fixed on the support base 14. Measuring the pulsed X-ray dose distribution via the arrangement as in fig. 2; the current measuring system comprises a differential Rogowski coil 16, a data transmission unit and a data acquisition unit, wherein the Rogowski coil 16 is positioned at the same position with the dose piece and is vertical to the direction of the pulse X-ray, so that electrons in a radiation field completely pass through the Rogowski coil 16; the ratio of the number of photons to the number of electrons is calculated from the dose, the energy spectrum and the current value.

The diode anode composite target and fixing structure 15 is fixed by a polyethylene film pressure ring 6 and a metal conversion target fixing structure 7, wherein the polyethylene film pressure ring 6 is used for fixing a polyethylene film, and the polyethylene film absorbs electrons after the metal conversion target 5.

The dose plate holder base plate 10, cover plate 11, set screws 12 and support base 14 in the dose measuring system are made of polyethylene and nylon; wherein, the dosage sheet support bottom plate 10 is provided with 21 grooves which have a distance of 1cm and are mutually vertical in the radius direction, and dosage sheets 13 are placed in the grooves; the cover plate 11 is 1mm thick and is fixed to the dose plate holder base plate 10 by screws 12.

The Rogowski coil 16 is made of a nylon material with a rectangular cross section as a framework, 100 turns of differential winding are wound, a stainless steel shell is shielded and protected, a measurement signal is output through a BNC cable head on the stainless steel shell, and the stainless steel shell is insulated from a shell of the pulse X-ray system and is not grounded.

The current signal is connected with a data acquisition system through a data transmission system; the data transmission system comprises a coaxial cable and a cable joint, wherein a cable shielding layer of the coaxial cable is insulated from a shell of the pulse X-ray system, is not in common ground, and reduces interference.

The data acquisition system comprises an oscilloscope and software, wherein the software is compiled by Matlab program and is used for integral processing of current waveform.

Further, the photon number is obtained by the energy spectrum and the dose calculation of the pulse X-ray;

furthermore, the electronic number is obtained by integrating the current measured by the Rogowski coil in the pulse X-ray generation time, and the current is the sensitivity obtained by dividing the voltage signal of the oscilloscope by calibration;

further, the ratio of the number of photons to the number of electrons in the radiation field is obtained by calculation.

As shown in FIG. 4, the dose distribution plot of the dose in the radiation field according to the experiment of the present invention is larger when the dose plate 13 is located within + -5 cm from the center.

The invention provides a method for measuring by using a device for measuring the ratio of the number of photons to the number of electrons in a pulsed X-ray radiation field, which comprises the following steps:

firstly, a dose measuring system is used for measuring to obtain pulse X-ray dose distribution and calculating total dose, and photon number is calculated according to the total dose and the energy spectrum distribution of the pulse X-ray.

The area represented by the measurement of each dose patch 13 increases with the radius, and the total dose for the measurement area is determined by area weighting. The dose of pulsed X-rays generally refers to the absorbed dose, i.e., the average energy imparted by ionizing radiation to a substance per unit volume. Under the condition of the same total energy, the absorbed doses of X-rays of different energy pulses are different, and the dose of a low energy section is stronger. The pulse X-ray energy spectrum obtains the share of the pulse X-rays in different energy bands, the photon fluence, namely the photon number in unit area, is calculated according to the conversion relation between the absorption dose and the photon fluence of the pulse X-rays in different energy bands, and the total photon number is obtained by multiplying the photon number by the irradiation area. The mean pulse X-ray dose measured in the preferred embodiment of the present invention is 50.5mGy, the dose distribution is shown in FIG. 4, and the number of photons obtained from the pulse X-ray energy spectrum is 3.9X 10¹³。

And secondly, measuring the current by using a current measuring system, and obtaining the electron number in the radiation field by using the current.

Signals of the Rogowski coil 16 in the current measuring system are transmitted to an oscilloscope through a data transmission system, and voltage signals acquired by the oscilloscope are divided by the calibrated sensitivity of the Rogowski coil 16 to be current signals in a radiation field. The current signal is integrated over the pulse time to obtain the total charge of electrons in the radiation field, and the total charge is divided by the electron charge to obtain the number of electrons in the radiation field. In the preferred embodiment of the invention, the total amount of transmitted electrons in the radiation field measured by the Rogowski coil 16 is 1.14nC, and the number of electrons in the radiation field is 7.1X 10⁹。

Thirdly, the ratio of the number of photons to the number of electrons is calculated, and in the preferred embodiment of the invention, the ratio of the number of photons to the number of electrons is 5493: 1. The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.