An experimental method for identifying heavy ion species using characteristic X-rays

Abstract

The present invention relates to an experimental method for identifying heavy ion types using characteristic X-rays, and belongs to the technical field of heavy ion type identification. The method comprises the following steps: S1, selecting a suitable collision target material according to the type of heavy ion to be identified; S2, selecting a suitable X-ray detector according to the difference in Kα-X-ray energy generated by the heavy ion to be identified and the target material; S3, using a standard radioactive source to perform energy calibration on the detector; S4, placing the collision target material in a vacuum target chamber, placing the X-ray detector at the transparent window position of the vacuum target chamber, and starting to measure the characteristic X-ray energy; S5, comparing the experimentally measured heavy ion characteristic X-ray energy with the heavy ion characteristic X-ray energy data obtained by querying, so as to identify the heavy ion type. The method provided by the present invention utilizes the different characteristic X-ray energies generated by different atoms to identify the ion types generated by a mixed ion source, thereby ensuring the heavy ion types used in the experiment.

Description

Technical Field

[0001] The invention belongs to the technical field of heavy ion type identification, and specifically is an experimental method for identifying heavy ion types using characteristic X-rays. Background Art

[0002] The basic principle of hybrid ion acceleration technology is that different elements with the same charge-to-mass ratio can be accelerated using the same isochronous magnetic field and acceleration frequency. In the 1990s, Lawrence Berkeley Laboratory used two sets of light and heavy hybrid beams, involving ion types 11 B 3+ , 18 O 5+ , 22 Ne 6+ , 40 Ar 11+ , 51 V 14+ , 65 Cu 18+ , 86 K 21+ , 136 XE 38+ , using mixed beams for irradiation experiments can cover a wider LET range. The cyclotron CYCLONE of the University of Leuven in Belgium was funded by the European Space Agency (ESA) and other institutions to establish a heavy ion single particle effect irradiation device. The main ions of the mixed beam it produces are 10 B 2+ , 15 N 3+ , 20 Ne 4+ , 40 Ar 8+ , 84 K 17+ , 132 XE 26+ The main components of the mixed beam produced by the cyclotron of the Japan Atomic Energy Research Center are 4 He + , 12 C 3+ , 16 O 4+ , 20 Ne 5+ , 40 Ar 10+ , 84 K 21+ .

[0003] Different ions are needed to conduct research on heavy ion single particle effects. Among them, the ECR source is an important ion source introduction system, which can mix and match elements such as N, Ne, Si, Ar, Fe, Kr, and Xe. In order to ensure the accuracy of single particle test assessment, the types of ions must be identified. However, the mixed ion acceleration technology requires that the ions have the same charge-to-mass ratio, which brings certain difficulties to the identification of ion types. If the ordinary mass spectrometry method of magnetic field and electric field is used to select ions, then the biggest limitation encountered when facing heavier ions is that the mass resolution is first required to be extremely high, which will affect the ion transmission efficiency.

[0004] In addition, isotopes are identified by combining ordinary mass spectrometry with time-of-flight analysis, because the difference in isotope mass leads to a difference in flight time, thereby eliminating interference. The ΔE-E method is applicable to nuclides with Z≤20 and has requirements for ion energy. The full stripping method and gas-filled magnetic spectrometer both have relatively high requirements for ion energy. Summary of the invention

[0005] In order to solve the defects of the prior art, the purpose of the present invention is to provide an experimental method for identifying the types of heavy ions using characteristic X-rays. This method uses the different energies of characteristic X-rays produced by different atoms to identify the types of ions produced by a mixed ion source, thereby ensuring the types of heavy ions used in the experiment.

[0006] In order to achieve the above purpose, a technical solution adopted by the present invention is:

[0007] An experimental method for identifying heavy ion types using characteristic X-rays, the method is based on an experimental device for identifying heavy ion types using characteristic X-rays, the experimental device comprising a heavy ion source, a vacuum target chamber, an X-ray detector and a computer, the vacuum target chamber is located at the exit of the heavy ion source, a collision target material is placed in the vacuum target chamber; the X-ray detector is arranged at a transparent window outside the vacuum target chamber, and the X-ray detector is connected to the computer for communication;

[0008] The method comprises the following steps:

[0009] S1. Select appropriate collision target material according to the type of heavy ions to be identified;

[0010] S2, according to the K generated by the heavy ions to be identified and the collision target α -Difference in X-ray energy, select the appropriate X-ray detector;

[0011] S3, using a standard radiation source to calibrate the energy of the X-ray detector;

[0012] S4, placing the collision target in the vacuum target chamber, placing the X-ray detector at the transparent window position of the vacuum target chamber, and starting to measure the characteristic X-ray energy;

[0013] S5. Compare the experimentally measured heavy ion characteristic X-ray energy data with the heavy ion characteristic X-ray energy data obtained by query, so as to identify the type of heavy ions.

[0014] Furthermore, in the experimental method of using characteristic X-rays to identify the types of heavy ions as described above, the heavy ion rays generated by the heavy ion source are incident on the collision target at a direction of 45 degrees to the collision target, generating characteristic X-rays.

[0015] Furthermore, in the experimental method for identifying heavy ion types using characteristic X-rays as described above, the principle for selecting the collision target in step S1 is that the atomic number of the collision target is 4 or 5 higher than the atomic number of the heavy ion to be identified.

[0016] Furthermore, in the experimental method for identifying heavy ion species using characteristic X-rays as described above, the collision target material selected in step S1 is titanium.

[0017] Furthermore, in the experimental method for identifying heavy ion species using characteristic X-rays as described above, the size of the collision target is 12 mm×12 mm, and the surface density is 2.3 mg / cm 2 .

[0018] Further, in the experimental method of using characteristic X-rays to identify the types of heavy ions as described above, the energy resolution of the X-ray detector selected in step S2 must be smaller than the energy resolution of the heavy ions to be identified and the K generated by the collision target. α -Difference in X-ray energy.

[0019] Furthermore, in the experimental method of using characteristic X-rays to identify heavy ion species as described above, a Si(Li) detector is selected in step S2, and its energy resolution is 125 eV.

[0020] Further, in the experimental method of using characteristic X-rays to identify heavy ion species as described above, the standard radiation source used in step S3 is 241 Am and 55 Fe, of which 241 The characteristic peak energies of Am are 11.9keV, 13.9keV and 17keV. 55 The characteristic peak energy of Fe is 5.69 keV.

[0021] The experimental method of using characteristic X-rays to identify heavy ion species according to the present invention has the following significant technical effects:

[0022] (1) The method of the present invention can make up for the problem of difficulty in identifying ion types due to similar charge-to-mass ratios in mixed ion source technology, and is conducive to selecting different ions for experiments;

[0023] (2) The method described in the present invention can be used to study the quality of the beam produced by the accelerator and whether it contains other heavy ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A flow chart of an experimental method for identifying heavy ion species using characteristic X-rays provided in an embodiment of the present invention;

[0025] Figure 2 for Figure 1 Schematic diagram of the experimental device structure used in the experimental method. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with specific embodiments and the accompanying drawings.

[0027] In order to use the different energies of atomic characteristic X-rays to identify the ion types produced by the mixed ion source, the following problems need to be solved: first, to select a suitable collision target material; second, to select a detector that can detect lower energy characteristic X-rays.

[0028] In order to solve the above problems, the present invention provides an experimental method for identifying heavy ion species using characteristic X-rays. Figure 1 The experimental method flow chart is shown. This method is based on the ECR ion source of the heavy ion cyclotron accelerator of China Atomic Energy Research Institute, and the relevant experimental equipment is arranged at the vacuum target chamber at the exit of the ion source. Figure 2 A structural schematic diagram of the experimental device used is shown, which includes a heavy ion cyclotron ECR ion source, a vacuum target chamber, an X-ray detector and a computer. The vacuum target chamber is located at the exit of the heavy ion cyclotron ECR ion source, and a collision target material is placed in the vacuum target chamber so that the heavy ion rays generated by the heavy ion cyclotron ECR ion source can be incident on the collision target material at a 45-degree direction, thereby generating characteristic X-rays; the X-ray detector is arranged at a transparent window outside the vacuum target chamber, and the X-ray detector transmits energy data of the detected characteristic X-rays to the computer, and the computer obtains the energy data and performs data analysis.

[0029] The above experimental method for identifying heavy ion species using characteristic X-rays comprises the following steps:

[0030] S1. Select appropriate collision target material according to the type of heavy ions to be identified.

[0031] Different target materials have different yields of characteristic X-rays for different ions. The KX cross-sections produced by the collision of incident ions with different target materials are different. Experimental studies have shown that when the atomic number of the target material is 4 or 5 higher than the atomic number of the incident ion, the KX-ray cross-section is higher, and the X-ray yield is greater under the same conditions, which is convenient for detection. In this embodiment, for the KX cross-section of argon (Ar) ions, the target material selected is titanium (Ti).

[0032] In this embodiment, the target size is 12 mm × 12 mm, and the target surface density is 2.3 mg / cm 2 .

[0033] S2, based on the K generated by the heavy ions to be identified and the collision target α -Difference in X-ray energy, select the appropriate X-ray detector.

[0034] In this embodiment, K generated by Ar ions α -X-ray energy is about 2.6-2.9keV, K of Ti α -X-ray energy is 4.551keV, and the difference between the two is about 1.6-1.9keV, so the energy resolution of the selected X-ray detector needs to be smaller than the difference between the two. In this embodiment, a Si (Li) detector is selected, the model is the XR-100SDD silicon drift detector (SDD) developed by AMPTEK, and its energy resolution is 125eV.

[0035] S3. Use a standard radiation source to calibrate the energy of the X-ray detector.

[0036] In this embodiment, a standard radiation source is used. 241 Am and 55 Fe is used to calibrate the energy of the X-ray detector, where 241 The characteristic peak energies of Am are 11.9keV, 13.9keV and 17keV. 55 The characteristic peak energy of Fe is 5.69 keV.

[0037] S4. Place the collision target in the vacuum target chamber, place the X-ray detector at the transparent window position of the vacuum target chamber, and start measuring the characteristic X-ray energy.

[0038] S5. Compare the experimentally measured heavy ion characteristic X-ray energy data with the heavy ion characteristic X-ray energy data obtained by query, so as to identify the type of heavy ions.

[0039] The experimental method for identifying heavy ion types using characteristic X-rays provided by the present invention can make up for the problem in mixed ion source technology that ion types are difficult to identify due to similar charge-to-mass ratios, and is conducive to selecting different ions for experiments; it can study the quality of the beam generated by the accelerator and whether it contains other heavy ions.

[0040] The above embodiments are merely illustrative of the present invention, and the present invention may also be implemented in other specific ways or other specific forms without departing from the gist or essential features of the present invention. Therefore, the described embodiments should be considered illustrative rather than restrictive in any respect. The scope of the present invention should be described by the appended claims, and any changes equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. An experimental method for identifying heavy ion species using characteristic X-rays, the method is based on an experimental device for identifying heavy ion species using characteristic X-rays, the experimental device comprising a heavy ion source, a vacuum target chamber, an X-ray detector and a computer, the vacuum target chamber is located at the exit of the heavy ion source, a collision target material is placed in the vacuum target chamber; the X-ray detector is arranged at a transparent window outside the vacuum target chamber, and the X-ray detector is connected to the computer for communication; The method comprises the following steps: S1. Select a suitable collision target material according to the type of heavy ions to be identified. The principle for selecting the collision target material is that the atomic number of the collision target material is 4 or 5 higher than the atomic number of the heavy ions to be identified. S2, selecting a suitable X-ray detector according to the difference in energy between the heavy ions to be identified and the Kα-X-rays generated by the collision target; S3, using a standard radiation source to calibrate the energy of the X-ray detector; S4, placing the collision target in the vacuum target chamber, placing the X-ray detector at the transparent window position of the vacuum target chamber, and starting to measure the characteristic X-ray energy; S5. Compare the experimentally measured heavy ion characteristic X-ray energy data with the heavy ion characteristic X-ray energy data obtained by query, so as to identify the type of heavy ions.

2. The experimental method for identifying heavy ion species using characteristic X-rays according to claim 1, characterized in that: The heavy ion rays generated by the heavy ion source are incident on the collision target at a direction of 45 degrees to the collision target, thereby generating characteristic X-rays.

3. The experimental method for identifying heavy ion species using characteristic X-rays according to claim 1 or 2, characterized in that: The collision target material selected in step S1 is titanium.

4. The experimental method for identifying heavy ion species using characteristic X-rays according to claim 3, characterized in that: The size of the collision target is 12 mm × 12 mm, and the surface density is 2.3 mg / cm 2 .

5. The experimental method for identifying heavy ion species using characteristic X-rays according to claim 1, characterized in that: The energy resolution of the X-ray detector selected in step S2 needs to be smaller than the energy difference between the heavy ions to be identified and the Kα-X-rays generated by the collision target.

6. The experimental method for identifying heavy ion species using characteristic X-rays according to claim 5, characterized in that: In step S2, a Si (Li) detector is selected, and its energy resolution is 125 eV.

7. The experimental method for identifying heavy ion species using characteristic X-rays according to claim 5 or 6, characterized in that: The standard radiation source used in step S3 is 241 Am and 55 Fe, of which 241 The characteristic peak energies of Am are 11.9keV, 13.9keV and 17keV. 55 The characteristic peak energy of Fe is 5.69 keV.

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