A full digital two -dimensional conforms to the Doppler widening system

Abstract

The invention relates to nuclear electronics technology, in particular to an all-digital two-dimensional coincidence Doppler broadening system, comprising first and second detectors and a host computer; also comprising first and second acquisition channels with the same structure, FPGA digital The processing platform and the Gigabit Ethernet port; the first and second detectors are respectively connected with the first and second acquisition channels, and the FPGA digital processing platform is respectively connected with the first and second acquisition channels and the Gigabit Ethernet port. The Ethernet port is connected with the upper computer. The system simplifies the system design by adopting a dual-channel all-digital acquisition circuit, and implements pulse extraction, time scaling and time coincidence analysis in FPGA. The ADC is directly used to sample the pulse, and then it enters the FPGA digital processing platform for pulse shaping, baseline recovery, stacking identification, amplitude extraction, and time scaling to improve the Doppler broadening spectrum peak-to-book ratio by 2-3 orders of magnitude.

Description

technical field [0001] The invention belongs to the technical field of nuclear electronics, in particular to an all-digital two-dimensional coincidence Doppler broadening system. Background technique [0002] Positron annihilation Doppler broadening measurement technology is an important technical means to study the internal microstructure and atomic-level defects of materials. Positron annihilation spectroscopy studies vacancy-type defects based on the information of electron density and electron momentum density brought by annihilation radiation. The low-momentum part of the Doppler-broadened spectrum corresponds to the momentum information of the annihilation of positrons and conduction electrons or valence electrons, while the high-momentum part mainly reflects the momentum distribution information of the core electrons. Because the core electrons have specific binding energies to the nucleus, the high-momentum components of the annihilation radiation carry very detaile...

AI Technical Summary

Problems solved by technology

However, because the analog signal takes a long time to form, it is easy to generate accumulation, which is not conducive to high count rate measurement; at the same time, the accuracy and speed of the ADC sampling rate are low, so that the resolution of the energy spectrum is low

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