CzT radiation detection device based on three-dimensional electrode and particle discrimination method

Abstract

The application provides a CZT radiation detection device based on a three-dimensional electrode and a particle discrimination method, aiming at discriminating alpha, beta and gamma from the source. The CZT radiation detection device adopts a cathode as a radiation incident window, and shallow layer induction electrodes and deep layer collection electrodes are arranged on the side of the crystal, and an anode is arranged on the surface opposite to the cathode, thereby forming a three-dimensional electrode system. The application utilizes the essential difference in the action depth of alpha, beta and gamma rays in the CZT crystal, and the unique'strong / weak' combination characteristics of the electrode signals, and realizes high-fidelity discrimination of alpha, beta and gamma in the mixed radiation field through the signal distribution characteristics that alpha particles generate strong signals in the shallow layer induction electrodes, the energy deposition depth of beta particles in the CZT crystal has low dispersion, and the energy deposition depth of gamma rays in the CZT crystal has high dispersion.

Claims

1. A CZT radiation detection device based on three-dimensional solid electrodes, comprising a CZT crystal, characterized in that, Also includes: A cathode covering the first surface of the CZT crystal serves as a radiation incident window; An anode covering the second surface of the CZT crystal; The second surface is opposite to the first surface; A shallow sensing electrode is disposed on the side of the CZT crystal near the first surface; A deep collection electrode is disposed on the side of the CZT crystal and located below the shallow sensing electrode. An insulating isolation groove is disposed on the side of the CZT crystal and located between the cathode and the shallow sensing electrode, between the shallow sensing electrode and the deep collecting electrode, and between the deep collecting electrode and the anode. The signal acquisition and processing unit includes a signal acquisition module, a clock synchronization module, an analog-to-digital conversion module, and a signal processing module. The signal acquisition module includes three independent charge-sensitive preamplifiers connected to the shallow sensing electrode, the deep collecting electrode, and the anode, respectively. The clock synchronization module provides synchronous trigger signals to each charge-sensitive preamplifier to ensure synchronous acquisition. The analog-to-digital conversion module is connected to the output of each charge-sensitive preamplifier to digitize the waveform; the signal processing module receives and processes the digitized signal.

2. The CZT radiation detection device based on three-dimensional electrodes according to claim 1, characterized in that: The CZT crystal is a cuboid.

3. The CZT radiation detection device based on a three-dimensional electrode according to claim 1 or 2, characterized in that: The width of the shallow sensing electrode is 100-150 µm; The width of the deep collection electrode is 2000-2500 µm; The width of the insulating isolation groove is 100-2500 µm, and the insulating isolation groove is filled with a material with a dielectric constant greater than 8.

4. The CZT radiation detection device based on a three-dimensional electrode according to claim 3, characterized in that: The cathode surface is provided with a gradient doped layer, the doping concentration of the gradient doped layer decreases from the surface linearly to the interior ; The cathode is a metal electrode with a thickness of 20 nm to 1 μm.

5. The CZT radiation detection device based on a three-dimensional electrode according to claim 4, characterized in that: The anode is a metal electrode with a thickness of 20 nm to 1 μm.

6. The CZT radiation detection device based on a three-dimensional electrode according to claim 5, characterized in that: Both the shallow sensing electrode and the deep collecting electrode are made of gold.

7. The CZT radiation detection device based on a three-dimensional electrode according to claim 6, characterized in that: The material filled in the insulating groove is .

8. The CZT radiation detection device based on a three-dimensional electrode according to claim 4, characterized in that: The gradient doped layer is boron doped.

9. A particle discrimination method for a CZT radiation detection device based on three-dimensional electrodes, characterized in that, Includes the following steps: 1) Using any one of the three-dimensional electrode-based CZT radiation detection devices described in claims 1-8, the peak amplitude of shallow induction electrode signals is simultaneously acquired and extracted. Peak amplitude of deep collection electrode signal and peak amplitude of anode signal ; 2) Determine the peak amplitude of the shallow induction electrode signal Is it greater than or equal to the first threshold Thr1? If it is greater than or equal to the first threshold Thr1, it is an alpha particle event; Otherwise, proceed to step 3). 3) Determine whether the energy deposition depth dispersion parameter K is less than the second threshold Thr2; If the value is less than the second threshold Thr2, it is a β particle event; Otherwise, it is a gamma-ray event; The formula for calculating the energy deposition depth dispersion parameter K is as follows: .

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