Novel digital beta <+>-gamma coincidence positron annihilation lifetime spectrum system

Abstract

The invention relates to the technology of nuclear electronics and nuclear detectors and specifically relates to a novel digital beta <+>-gamma coincidence positron annihilation lifetime spectrum system. The system comprises samples, a radioactive source, an avalanche diode, a vacuum chamber, a three-dimensional mobile device, a first coaxial electromagnetic lens, a second coaxial electromagneticlens, a first BaF2 scintillator detector, a second BaF2 scintillator detector, a first high-voltage power supply, a second high-voltage power supply, a third high-voltage power supply, a pre-amplifier, a first constant fraction timing discriminator, a second constant fraction timing discriminator, a third constant fraction timing discriminator, a coincidence device and a digital oscilloscope. Thesystem enables the radioactive source and the samples to be separated, adopts the avalanche diode to replace a plastic scintillator to serve as an initial signal generator, has higher time resolution,is simple in structure and convenient to measure, and can realize real-time in-situ measurement under conditions of high temperature, high stress and changes (stretch, distortion and the like) of sample structures.

Description

technical field [0001] The invention belongs to the technical field of nuclear electronics and nuclear detectors, and in particular relates to a new type of digital beta + -γ conforms to the positron annihilation lifetime spectrum system. Background technique [0002] As the antimatter of electrons, positrons are of great significance in the study of defects in the microstructure of materials. Since the vacancy-type defect in the material lacks positively charged atoms and is negatively charged, it can capture positrons. Therefore, the more defects in the material, the greater the proportion of positrons captured by defects. As a non-destructive testing technique, positron annihilation technology has been widely used in the detection and characterization of material defects due to its non-destructive, high sensitivity and convenient use. The conventional positron annihilation lifetime spectrum is measured using a "sandwich" sandwich structure, that is, "sample-radiation so...

AI Technical Summary

Problems solved by technology

The conventional positron annihilation lifetime spectrum is measured using a "sandwich" sandwich structure, that is, "sample-radiation source-sample". The close contact between the radiation source and the sample greatly limits the measurement range of positrons, such as high temperature, high stress and Dynamic measurement of real-time deformation of the sample; in addition, there are many nuclear electronic devices that make up the conventional positron annihilation lifetime spectroscopy system, which are relatively bulky and expensive. Positron annihilation lifetime results have large errors

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