An alpha and beta pulse discriminating method

Abstract

The invention relates to a discriminating method for alpha and beta particle pulses measured by an alpha and beta surface contamination instrument. The method comprises the steps of amplifying pulse signals generated by a photoelectric detector through a signal amplifier to form pulse signals for discrimination and record; converting the analog pulse signals into digital signals and sending digital signal pulses into a single-chip microcomputer directly; recording the time information of input of the digital signal pulses through the single-chip microcomputer and calculating the pulse width; comparing the calculated input pulse width and the width range of the alpha and beta particle pulses set in the single-chip microcomputer in advance to realize the discriminating of the alpha and beta pulses. With simple circuit design, the alpha and beta pulse discriminating method realizes the alpha and beta pulse discriminating and thus increases the alpha and beta particle discriminating efficiency.

Description

technical field [0001] The invention relates to the design technology of an α and β surface pollution meter, in particular to a method for discriminating α and β particle pulses measured by an α and β surface pollution meter. Background technique [0002] Portable α, β surface pollution meter, using a double scintillator and a photodetector device to realize the measurement of α, β surface pollution, wherein the double scintillator is composed of ZnS (Ag) scintillator coated on the plastic scintillator. During measurement, the α particles basically produce ionization effect and emit light only in the ZnS(Ag) scintillator, while the β particles mainly generate ionization effect and emit light in the plastic scintillator. Photodetection devices collect scintillation light and convert it into electrical signals to realize the measurement of α and β particles. Since the same photodetection device is used, the shape of the pulse signal generated by α and β particles is similar. ...

AI Technical Summary

Problems solved by technology

[0004] The first technical method requires the use of two probes. In actual measurement, the probes need to be switched manually for different particles, which is cumbersome to use, increases the measurement time, and has higher production costs and system complexity; the second technical method Among them, due to the difference in particle energy and incident angle, the energy deposited in the scintillator has a large range of variation, so the output pulse amplitude ranges of α and β particles overlap to a certain extent, and it is difficult to completely distinguish them by setting the amplitude interval ; On the basis of the second method, the third technical method changes the gain by adjusting the operating voltage of the photoelectric device, thereby increasing the amplitude difference of the α and β pulses and reducing the overlap of their amplitude ranges, but this method also requires manual replacement The measurement method cannot obtain α and β particle information at the same time; the fourth technical method is currently mainly used by foreign manufacturers. The screening of the falling edge time of the particle simulation pulse has a complicated circuit structure and is difficult to realize

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