Study of a large acceptance charged particle detector

We investigated basic characteristics of a new detector system, which has been designed to be used for nuclear data measurements. The detector has a large acceptance to cover a wide range of charged particle energies. The detector consists of crystal detectors and plastic scintillators. In this detector, energy measurements are carried out by adopting the pulse-height method for low-energy particles and for high-energy particles the time of flight (TOF) technique. The low-energy detector (crystals) plays also as a degrader for high-energy particles. One of important issues is the non-linearity of scintillation output for heavy ions of crystal detectors. The other issue is the deviation of a particle trajectory due to the multiple-scattering in the detector material. In the present study, we measured the scintillation output of detectors and the multiple-scattering effect on the TOF detection efficiency. Experiments were carried out at National Inst. of Radiological Sciences-Heavy Ion Medical Accelerator in Chiba (NIRS-HIMAC) for a crystal detector system by using protons and Ar ions. Finally, the scintillation nonlinearity has been determined. As for the multiple-scattering effect, we found that both of simulations, GEANT4 and PHITS tend to underestimate. (author)