Method for measuring the fluence of a hard x-ray area source

Abstract

The application discloses a kind of hard X-ray surface source energy injection quantity measurement method, solve the problem that the measurement result of existing calorimeter is low in large-area X-ray source measurement scene, measurement precision is low, specifically includes steps 1, in the radiation field of the hard X-ray surface source to be measured, set up calorimeter, make its normal line parallel with the normal line of the hard X-ray surface source to be measured, obtain the temperature difference before and after the absorption body of calorimeter is irradiated by the hard X-ray surface source to be measured;Step 2, through temperature difference Δ T Calculate the energy deposited in the absorption body of calorimeter;Step 3, calculate irradiation H by energy;Step 4, obtain photon incidence angle correction coefficient K1 and energy spectrum correction coefficient K2;Step 5, based on irradiation H, photon incidence angle correction coefficient K1 and energy spectrum correction coefficient K2 calculate the energy injection quantity of the hard X-ray surface source to be measured, complete the measurement of hard X-ray surface source energy injection quantity.

Description

Technical Field

[0001] This invention relates to energy flux measurement methods, specifically to a method for measuring the energy flux of a hard X-ray surface source. Background Technology

[0002] X-ray energy flux measurement is a core technology in the field of pulsed X-ray radiation parameter diagnosis. Currently, commonly used detectors for X-ray energy flux measurement include thermoluminescent dosimeters, scintillation detection systems, semiconductor detectors, air ionization chambers, and calorimeters. Among them, semiconductor detectors specifically include silicon photodiodes, diamond detectors, and other types.

[0003] The general measurement principle of the above-mentioned detectors is the same. Specifically, the X-rays incident on the detector surface deposit energy inside the detector. The detector captures characteristic parameters that are directly proportional to the X-ray energy flux. By detecting corresponding parameters such as thermoluminescence, charge, ionization energy, and temperature change, the energy flux value of the pulsed X-ray can be calculated, thus realizing the quantitative measurement of X-ray energy flux.

[0004] In X-ray diagnostic scenarios for laser fusion ignition devices, calorimeters are commonly used in the industry to measure X-ray energy flux. In this specific scenario, the X-ray radiation source of the laser fusion ignition device is a point source, with photons emitted at a 4π solid angle. The calorimeter is positioned far from the radiation source, allowing the incident radiation to be approximated as parallel light. Furthermore, the average energy of X-ray photons is low in this scenario; therefore, when using a calorimeter to measure energy flux, the measurement results do not require correction, and valid diagnostic data can be directly obtained.

[0005] However, existing calorimeter measurement technologies have significant limitations in application scenarios and technical defects, making them unsuitable for diagnosing large-area X-ray sources. When using calorimeters to measure the X-ray energy flux of large-area X-ray sources, the measured energy flux results are significantly lower than the true values ​​due to multiple factors such as detector placement, radiation spectrum, and irradiation area. This results in a substantial decrease in measurement accuracy, necessitating additional correction processing of the measurement results. Consequently, direct, accurate, and efficient measurements cannot be achieved, severely limiting the application scope and reliability of calorimeters in large-area X-ray source energy flux detection scenarios. Summary of the Invention

[0006] The purpose of this invention is to solve the technical problem that existing calorimeters provide low measurement results and have low measurement accuracy in large-area X-ray source measurement scenarios.

[0007] To achieve the above objectives, the present invention provides a method for measuring the energy flux of a hard X-ray surface source, the technical solution of which is as follows:

[0008] A method for measuring the energy flux of a hard X-ray surface source, used for areas larger than 100 cm². 2 The hard X-ray surface source is characterized by the following steps:

[0009] Step 1: Set up a calorimeter in the radiation field of the hard X-ray surface source to be tested, ensuring its normal is parallel to the normal of the hard X-ray surface source. Obtain the temperature difference of the calorimeter absorber before and after irradiation by the hard X-ray surface source. ;

[0010] Step 2, using temperature difference Computational calorimeter absorbs energy deposited in the body ;

[0011] Step 3, through energy Calculate the irradiance H;

[0012] Step 4: Obtain the photon incident angle correction coefficient K1 and the energy spectrum correction coefficient K2;

[0013] Step 5: Calculate the energy fluence of the hard X-ray surface source under test based on the irradiance H, the photon incident angle correction factor K1, and the energy spectrum correction factor K2. The measurement of the energy flux of the hard X-ray surface source was completed.

[0014] Furthermore, step 4 specifically includes:

[0015] Step 4.1: Obtain the photon incident angle correction coefficient K1;

[0016] When calorimeter 2 is located on the central axis of the hard X-ray surface source to be measured:

[0017]

[0018] Where R is the radius of the hard X-ray surface source luminescent disk to be tested, L is its brightness, t is the irradiation time, and h is the distance between the calorimeter and the hard X-ray surface source to be tested.

[0019] When the calorimeter is located outside the central axis of the hard X-ray surface source to be measured:

[0020]

[0021] Where d is the distance between the calorimeter and the central axis of the hard X-ray source to be measured, and r is the radius corresponding to each point on the hard X-ray source to be measured. The azimuth angle of calorimeter 2 in a spherical coordinate system centered at the center of the hard X-ray surface source 1 to be measured;

[0022] Step 4.2: Obtain the energy spectrum correction coefficient K2:

[0023]

[0024] Where E is the energy of the incident photon at the surface of the absorber.

[0025] Furthermore, step 2 specifically involves using temperature differences... Computational calorimeter absorbs energy deposited in the body :

[0026]

[0027] Where m is the mass of the absorber, c p This is the specific heat capacity of the absorber.

[0028] Furthermore, step 3 specifically involves using energy Calculate the radiation dose H:

[0029]

[0030] Where S is the surface area of ​​the absorber's light-facing side.

[0031] Further, step 5 specifically involves calculating the energy flux of the hard X-ray surface source 1 to be tested based on the irradiance H, the photon incident angle correction coefficient K1, and the energy spectrum correction coefficient K2. :

[0032]

[0033] Complete the measurement of the energy flux of the hard X-ray surface source.

[0034] The beneficial effects of this invention are:

[0035] 1. This invention provides a method for measuring the energy flux of a hard X-ray surface source, using a calorimeter on a surface with an area greater than 100 cm². 2 The measurement of the hard X-ray surface source was carried out. By calculating the measurement results and correcting them from the aspects of photon incident angle and energy spectrum, the measurement accuracy of the energy flux of the large-area hard X-ray surface source was greatly improved, and the problem of inaccurate energy flux measurement of the large-area hard X-ray surface source was solved.

[0036] 2. The present invention divides the method for obtaining the photon incident angle correction coefficient into two types: when the calorimeter is located on the central axis of the hard X-ray surface source and when the calorimeter is located outside the central axis of the hard X-ray surface source. Different calculation methods are used for different states, which can further improve the correction accuracy and thus improve the accuracy of the measurement results. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the parameters when the calorimeter is located on the central axis of the X-ray surface source to be measured in an embodiment of the present invention;

[0038] Figure 2This is a schematic diagram of the parameters when the calorimeter is located outside the central axis of the X-ray surface source to be measured in an embodiment of the present invention.

[0039] The attached figures are labeled as follows:

[0040] 1. Hard X-ray surface source to be tested; 2. Calorimeter. Detailed Implementation

[0041] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] This invention provides a method for measuring the energy flux of a hard X-ray surface source with an area of ​​100 cm². 2 The hard X-ray surface source specifically includes the following steps:

[0043] Step 1: Set up calorimeter 2 in the radiation field of the hard X-ray surface source 1 to be tested, so that its normal is parallel to the normal of the hard X-ray surface source 1 to be tested, and obtain the temperature difference of the absorber of calorimeter 2 before and after being irradiated by the hard X-ray surface source 1 to be tested. ;

[0044] In this embodiment, the calorimeter 2 uses a tantalum absorber with a diameter of 11 mm and a thickness of 1 mm.

[0045] Step 2, using temperature difference Computational calorimeter 2 absorbs energy deposited in the body :

[0046]

[0047] Where m is the mass of the absorber, c p The specific heat capacity of the absorber;

[0048] Step 3, through energy Calculate the radiation dose H:

[0049]

[0050] Where S is the surface area of ​​the absorber's light-facing side;

[0051] Step 4: Obtain the photon incident angle correction coefficient K1 and the energy spectrum correction coefficient K2;

[0052] Step 4.1: Obtain the photon incident angle correction coefficient K1;

[0053] like Figure 1As shown, when calorimeter 2 is located on the central axis of the hard X-ray surface source 1 to be measured:

[0054]

[0055] Where R is the radius of the luminous disk of the hard X-ray surface source 1 to be tested, L is its brightness, t is the irradiation time, and h is the distance between the calorimeter 2 and the hard X-ray surface source 1 to be tested.

[0056] In this embodiment, the radius R of the luminescent disk of the hard X-ray surface source 1 to be tested is 20cm.

[0057] like Figure 2 As shown, when calorimeter 2 is located outside the central axis of the hard X-ray surface source 1 to be measured:

[0058]

[0059] Where d is the distance between calorimeter 2 and the central axis of the hard X-ray source 1 to be measured, and r is the radius corresponding to each point on the hard X-ray source 1 to be measured. The azimuth angle of calorimeter 2 in a spherical coordinate system centered at the center of the hard X-ray surface source 1 to be measured;

[0060] Step 4.2: Obtain the energy spectrum correction coefficient K2:

[0061]

[0062] Where E is the energy of the incident photon at the surface of the absorber;

[0063] According to calculations, in this embodiment, when the calorimeter 2 is directly above the hard X-ray surface source 1 at h=5cm, the photon incident angle correction coefficient K1 is 1.61 and the energy spectrum correction K2 is 1.2.

[0064] Step 5: Calculate the energy flux of the hard X-ray surface source 1 to be tested based on the irradiance H, the photon incident angle correction factor K1, and the energy spectrum correction factor K2. :

[0065]

[0066] Complete the measurement of the energy flux of the hard X-ray surface source.

[0067] In this embodiment, the irradiation dose H = 1 mJ / cm 2 Then the amount can be injected =1.932mJ / cm 2 This embodiment also used the dosage measurement results of the dosing tablets to perform a simulation back-calculation, obtaining an energy flux of 2.1 mJ / cm. 2Compared with the calculation results of this embodiment, the difference between the two is very small, which shows that the measurement method provided in this embodiment has greatly improved the measurement accuracy and the measurement efficiency.

[0068] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for measuring the energy flux of a hard X-ray surface source, used for areas larger than 100 cm². 2 A hard X-ray surface source, characterized in that, Includes the following steps: Step 1: Set up a calorimeter (2) in the radiation field of the hard X-ray surface source (1) to be tested, so that its normal is parallel to the normal of the hard X-ray surface source (1) to be tested, and obtain the temperature difference of the absorber of the calorimeter (2) before and after being irradiated by the hard X-ray surface source (1). ; Step 2, using temperature difference Computational calorimeter (2) absorbs energy deposited in the body ; Step 3, through energy Calculate the irradiance H; Step 4: Obtain the photon incident angle correction coefficient K1 and the energy spectrum correction coefficient K2; Step 5: Calculate the energy flux of the hard X-ray surface source to be tested based on the irradiance H, the photon incident angle correction factor K1, and the energy spectrum correction factor K2. (1) The measurement of the energy flux of the hard X-ray surface source was completed.

2. The method for measuring the energy flux of a hard X-ray surface source according to claim 1, characterized in that, Step 4 specifically includes: Step 4.1: Obtain the photon incident angle correction coefficient K1; When calorimeter 2 is located on the central axis of the hard X-ray surface source (1) to be measured: ； Where R is the radius of the luminous disk of the hard X-ray surface source (1) to be tested, L is its brightness, t is the irradiation time, and h is the distance between the calorimeter (2) and the hard X-ray surface source (1) to be tested. When the calorimeter (2) is located outside the central axis of the hard X-ray surface source (1) to be measured: ； Where d is the distance between the calorimeter (2) and the central axis of the hard X-ray surface source (1) to be measured, and r is the radius corresponding to each point on the hard X-ray surface source (1) to be measured. The azimuth angle of calorimeter 2 in a spherical coordinate system centered at the center of the hard X-ray surface source 1 to be measured; Step 4.2: Obtain the energy spectrum correction coefficient K2: ； Where E is the energy of the incident photon at the surface of the absorber.

3. The method for measuring the energy flux of a hard X-ray surface source according to claim 1 or 2, characterized in that: Step 2 specifically involves calculating the energy deposited in the body by the calorimeter (2) through the temperature difference ∆T. : ； Where m is the mass of the absorber, c p This is the specific heat capacity of the absorber.

4. The method for measuring the energy flux of a hard X-ray surface source according to claim 3, characterized in that: Step 3 specifically involves using energy Calculate the radiation dose H: ； Where S is the surface area of ​​the absorber's light-facing side.

5. The method for measuring the energy flux of a hard X-ray surface source according to claim 4, characterized in that: Step 5 specifically involves calculating the energy flux of the hard X-ray surface source 1 to be tested based on the irradiance H, the photon incident angle correction factor K1, and the energy spectrum correction factor K2. : ； Complete the measurement of the energy flux of the hard X-ray surface source.

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