Experimental study on the sensitivity to gamma ray for a ST-401 film detector

The experiment study of the sensitivity to gamma rays is very important for a physics performance of ST-401 scintilling-film detector. In this paper, the basic principle and structure design of the scintilling-film detector is introduced, and calibration sensitivity experiments have been carried out at Cobalt-60 standard radiation source in Northwest Institute of Nuclear Technology. The uncertainties of experimental data are discussed in detail. In the end, the sensitivity of the detector to gamma rays versus the film thickness and the voltage of photomultiplier tube is provided as well.