Novel positron annihilation life time spectrometer

Abstract

The invention discloses a novel positron annihilation life time spectrometer. The positron annihilation life time spectrometer comprises a scintillation detector unit, wherein the scintillation detector unit is used for receiving gamma rays generated by disintegration of a radioactive source and positron annihilation and generating scintillation light; after being transmitted and modulated, the scintillation light enters a photocathode through a slit to generate photoelectrons; after being accelerated by a grid net, the photoelectrons enter a deflection plate and are deflected under the action of a high-frequency high-voltage electric field generated by a pulse signal source; after being multiplied and amplified by a micro channel plate, the deflected photoelectrons are imaged on a fluorescent screen; and an image acquisition and data analysis unit is used for reading the image on the fluorescent screen and carrying out on-line fitting on a single pulse signal according to position information to accurately obtain energy and generation time of the gamma rays. According to the positron annihilation life time spectrometer, the time resolution of the positron annihilation life time spectrometer can be effectively improved, the signal processing requirement of a system is reduced and the performance of the positron annihilation life time spectrometer is improved.

Description

technical field [0001] The invention relates to the technical field of nuclear electronics and nuclear detectors, in particular to a novel positron annihilation lifetime spectrometer. Background technique [0002] The positron is the antimatter of the electron, it interacts with matter, annihilates with the electron in the matter, and converts the entire mass into two gamma gamma rays with an energy of 0.511 MeV in opposite directions. The positron annihilation lifetime spectrometer is a sensitive tool for non-destructive detection of microstructural defects, charge density, and electron momentum density in material samples such as metals, semiconductors, high-temperature superconductors, and polymers by using the annihilation characteristics of positrons. It has high detection sensitivity and can It has the advantages of semi-quantitative analysis of defect concentration and depth distribution detection of defects. The annihilation lifetime of a positron is the time interv...

AI Technical Summary

Problems solved by technology

In the above-mentioned existing positron annihilation lifetime spectrometer scheme, the fixed scintillator material (BaF 2 ) in the case of using photomultiplier tubes and analog / digital circuits to convert and collect the start and end channel signals. It is difficult to further increase the sampling frequency of digital electronics, so it is difficult to increase the positron annihilation life The time resolution of the spectrometer affects the performance of the positron annihilation lifetime spectrometer

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