Most versatile radiation intensity The measurement method is to record the number of incident particles in a certain time one by one, such as measuring various radiation source Or the radiation intensity of radioactive substances. This method can be used for the measurement of various nuclear reaction cross sections, life measurement of radioactive nuclei, neutron flux monitoring, calibration of radioactive sources and measurement of environmental pollution, as well as the relative and absolute measurement of other various radioactive intensities. The basic composition of the radiation intensity measurement system, in addition to the detector and its power supply, generally includes pre amplification, main amplification, pulse discrimination and shaping circuits, and finally the counting circuit records. However, in practical applications, in order to improve the sensitivity and give accurate data, some other specific electronic methods need to be used. For example, when measuring low-level radioactivity, the common methods of coincidence and anti coincidence are to eliminate the interference of various environmental background as far as possible. When multiple detectors are combined to improve detection efficiency, it is necessary to accurately add the signals output by each detector. Especially when absolutely measuring the radiation intensity, the detection efficiency of the detector must be strictly calibrated with the electronic circuit first, and the errors that may occur in the measurement (such as the counting loss caused by the dead time of the instrument and the error caused by accidental coincidence) must be corrected. In modern times, computers are also widely used to process the measured data in order to give various more intuitive physical results. In some special cases, it is often impossible to measure the number of incident particles one by one to determine the radiation intensity. For example, in the case of strong pulsed radiation fields, including nuclear explosion measurement, high current pulse accelerator, nuclear fusion experiments, etc., because they all generate extremely strong radiation pulses in a very short time (nanosecond), At this time, we can only try to measure the change of its total radiation intensity with time. The whole electronic measurement system, including information acquisition, transmission and recording, is required to have fast enough response time and maintain good linear response to the signal amplitude in a large dynamic range.
