Research Of A Cadmium Tungstate Scintillation Detector Based On Silicon Photomultiplier Tube

X-ray industrial computed tomography(CT)is an advanced NDT technology.It can obtain the object structure of high resolution image.The technology has a wide range of applications in the industrial testing,advanced manufacturing,defense security and scientific archaeology.According to the different energy,X-ray can be divided into the high-energy industrial computed tomography(CT)based on linear accelerator and the low-power industrial computed tomography(CT).The high-energy industrial computed tomography(CT)has high energy,large doses and short scan time,so it puts forward higher requirements to the CT detector.Traditional high-energy CT detector used photodiode array or CCD array to detect the X-ray.With the development of new type of photoelectric detectors,the technology which based on the silicon photomultiplier tube developed CT detector is possible.We aimed at 6-mV X-ray detection,based on single point type silicon photomultiplier tube and cadmium tungstate scintillator developed a small scintillation detector.The work mainly included:1)Scintillation properties of Monte Carlo simulation.Based on the GEANT4 simulation software,we simulated the light output,energy deposition and detection efficiency for different scintillator types and different size of scintillators,the results could provide a reference for the detector design.The results showed that cadmium tungstate scintillator in such aspects as conversion efficiency,universal peak efficiency were superior to the other scintillators.And cadmium tungstate scintillator detection efficiency only depends on the height of the scintillator but has nothing to do with scintillation's side area.Scintillator energy deposition depends not only on the height of scintillators but also side area.2)Test for the properties of scintillators.We measured the luminous decay time,light output,energy resolution and afterglow for different scintillator types and different size of scintillators.We also put forward a test method of comparing with the mono-photoelectron.Test results showed that cadmium tungstate scintillators' light output could reach 12203ph/MeV,luminous decay time was between 11.3 and 12.0 us,the energy resolution of 10.8% at 661.6keV photo-peak for 137 Cs and the scintillation less affected by the afterglow.3)Research of the small scintillation detector.Based on cadmium tungstate scintillator and silicon photomultiplier tubes,we made a small scintillation detector.We completed the performance test,the front of readout circuit design and structure design of the detector.The detector's energy resolution of 19.2% at 661.6keV photo-peak for 137 Cs.The experimental test was carried out under the 6MV accelerator,test result showed that the detector function was normal and the detector could be used for high energy X-ray detection,the result also provided the research basis for the futher study of line array detector.