Positive electron annihilation angle correlation spectrometer

Abstract

The embodiment of the invention discloses a positive electron annihilation angle correlation spectrometer. The positive electron annihilation angle correlation spectrometer comprises a radioactive source, a first detector module and a second detector module, a coincidence unit and a data processing unit, wherein positive electrons generated by the radioactive source enter a sample to be slowed down, diffused and finally annihilated to generate two gamma rays, wherein the generated gamma rays respectively enter two detectors; the first detector module and the second detector module are fixed detectors; a scintillator of the first detector module is a whole crystal; a scintillator of the second detector module comprises a plurality of crystal bars which are linearly arranged along the direction of a narrow slit; and different crystal bars correspond to different included angles theta. By the positive electron annihilation angle correlation spectrometer, angle scanning can be avoided and a one-dimensional angle correlation spectrum can be obtained directly, and thus all angles can be measured once, thereby reducing test time, effectively improving the counting rate and improving testing performance of the system.

Description

technical field [0001] The invention relates to the field of nuclear application technology, in particular to a positron annihilation angle correlation spectrometer. Background technique [0002] Positron annihilation spectrometer is a sensitive tool for non-destructive detection of microstructure defects, charge density, electron momentum density, etc. in materials such as metals, semiconductors, high-temperature superconductors, and polymers. one. The positrons and electrons incident into the material are annihilated. According to the conservation of energy and momentum, the two gamma rays in opposite directions produced after the annihilation of the positrons will produce a certain angle with the 180° collinear line in addition to the Doppler effect. θ, so the positron annihilation momentum information can be obtained by Doppler broadening the energy spectrum and measuring the declination angle θ. [0003] In the prior art, the one-dimensional angle correlation device m...

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Problems solved by technology

[0004] However, in the structure of the above-mentioned prior art, in order to improve the angular resolution, the detector is usually far away from the sample, and the long collimation slit causes a large amount of counting loss, so the activity of the radioactive source is required to be large, and the angle-by-angle measurement makes Long test times for a single sample further complicate the system

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