Quality Control of High-Speed Photon Detectors

High-speed-photon detectors are some of the most important tools for observations of high energy cosmic rays. As technologies of photon detectors and their read-out electronics improved rapidly, the time resolution of some cosmic ray detectors became better than one nanosecond. To utilize such devices effectively, calibrations using a short-pulse light source are necessary. We have developed a pulsed laser of 80 picosecond width and adjustable peak intensity up to 100 mW. This pulsed laser is composed of a simple electric circuit and a laser diode. Details of this pulsed laser and its application for quality controls of photon detectors are reported in this contribution.

Intelligent pulse light source in the performance calibration system of two-dimensional neutron detector

Chinese Spallation Neutron Source (CSNS) project will use numerous two-dimensional (2D) neutron detectors whose ZnS (Ag) scintillator is doped with 6Li. To ensure the consistency of all neutron detectors, a calibration system for the performance of 2D neutron detectors is designed. For radiation protection, the state control of the radiation source gets more and more strict. It is impossible to directly carry out experiments with massive radioactive particles. Thus, the following scheme has been designed. The controlled pulsed laser light source on a 2D mobile platform is used to replace the neutron bombardment to generate the photon. The pulse signal drives the laser diode to generate pulse light. The pulse light source located on the 2D platform is controlled by the core controller, and goes to the wavelength shift fiber through the optical fiber. The host computer (PC) receives the signal from the electronics system, processes data, and automatically calibrates the performance parameters. As shown by the experimental results, the pulse light source can perfectly meet all requirements of 2D neutron detector calibration system.