Method for positron annihilation lifetime spectrum measurement, system and scintillation detector

Abstract

The invention relates to a method for positron annihilation lifetime spectrum measurement, a system for positron annihilation lifetime spectrum measurement, and a scintillation detector. The method for positron annihilation lifetime spectrum measurement includes the following steps that: a time point when a positron pulse bunch arrives at a sample to be measured is recorded as a first time point; a plurality of gamma photon signals generated by the annihilation of the positron pulse bunch in the sample to be measured are distinguished according to positions, and the plurality of gamma photon signals are collected, time points when the plurality of gamma photon signals are collected are recoded as a plurality of second time points; the plurality of second time points are processed, so that a plurality of first time differences can be obtained; and the plurality of first time differences are put into statistics, so that a positron annihilation lifetime spectrum can be obtained. With the method of the invention adopted, the time distribution of gamma photons generated by the annihilation of a plurality of positrons can be measured simultaneously, and therefore, measurement efficiency can be improved.

Description

technical field [0001] The invention relates to the technical field of nuclear spectroscopy and nuclear detection, in particular to a method, system and scintillation detector for positron annihilation lifetime spectrum measurement. Background technique [0002] The positrons emitted by the radioactive source are injected into the sample to be tested, and after thermal diffusion, they annihilate with the electrons in the sample to be tested, and emit gamma photons. The generation time of the gamma photons and the momentum and energy information they carry are respectively Corresponding to the lifetime of the positron in the material, the momentum and energy distribution information of the annihilated electron can reflect the microstructure of the sample material to be tested. [0003] The time that a positron exists in a solid sample, that is, the positron annihilation lifetime, is inversely proportional to the electron density in the sample to be tested, so the lifetime of ...

AI Technical Summary

Problems solved by technology

However, in the traditional measurement of positron annihilation lifetime spectrum, due to the stacking effect of the detector and the short annihilation time of positrons in the sample to be measured, a large number of positrons are annihilated almost simultaneously, and a positron pulse A large number of gamma photon signals (order of magnitude 10 5 ), the detector cannot simultaneously resolve so many gamma photon signals

The detector processes the superposition of all annihilation gamma photon signals in each positron pulse bunch as a single signal, and generally this processing will cause the detector stack to saturate and fail to work

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