Application Of Virtual Instrument In Particle Energy Spectrum Measurement System

Virtual instrument technology, which shares the advantages of visual effect, briefness, multiple functions and easy matching with other experimental instruments, is used a lot in applications of high-energy physics and nuclear physics experiment. In this paper, virtual instrument technology and LabVIEW were applied in high-energy physics and design of nuclear physics experiment, the cosmic trigger system and the light attenuation length measurement system of the liquid scintillator.Triggering system is the essential part in the high-energy physics and nuclear physics experiment, which directly influences the ruling out the bottom, setting the beginning of the time and restraining the detector. In this paper, cosmic ray detector was constructed by the directly coupling between the plastic scintillator and photomultiplier. Besides, based on the VME and NIM system, the electronic module of cosmic ray detector was constructed, including the discriminator, amplifier and QADC. Based on the LabVIEW platform, the cosmic ray signal read from VME highway was designed, in order to control several electronic behaviors of VME system in real time, including the data display, clear and save. The programs of reading and state judging of each register in VME system were also programmed.Amplitude spectrum curve was obtained by the way of multichannel analysis of digital signal with the help of LabVIEW program. Based on the virtual multichannel analyzer of VME and LabVIEW, a4096-channel’s amplitude spectrum analysis was realized, with the resolution of200fc. The final measured particles charge quantity is22.84pC. Besides, in this paper, the measurement results were compared with the test result of advanced sampling oscilloscope, and the both results coincide with each other well. Therefore, it was proved the measurement results can be obtained by the both of methods in real time.In this paper, the measurement system for the light attenuation length of liquid scintillator is also introduced. In our designed one-meter-length optical decay length measurement system, the NI PCI-6221was used as the control unit and signal read module, which is based on the responding control and data processing program of LabVIEW platform. The adjustment and control function for the LEDs and optical path system, liquid level of scintillator, optical signal measurement and subsequent data processing were realized.