Development of Cosmic Radiation and Energetic Particle Analyzing System: CREPAS

Information on accurate spectrum and its spatial distribution of energetic particles, particularly neutrons and heavy charged particles, are important for radiological protection of aircraft and spacecraft crew. However, precise dosimetry of those high-energy particles is still difficult since detected signals from different components are mixed and hardly separated with a conventional way. Thus, we have developed a new monitoring system having a phoswich-type scintillation detector coupled with a high-speed data acquisition unit which can measure 0 to 5 V signals from -20 to 400 ns with 2ns intervals; waveform data are transferred to a personal computer via the USB2.0 interface and stored in the 12bit dynamic range at the maximum rate of about 350 events per second. The signal waveforms are analyzed in on-line or off-line for discrimination of energetic radiation components such as neutrons, protons, heavy ions, muons in addition to photons and electrons. For feasibility testing, in-field cosmic radiation measurements were performed in a jet aircraft and at the summit of a high mountain using a prototype of the newly developed system. It was verified that this system can successfully detect cosmic-ray neutrons with the energy greater than 15MeV separately from other components, though further investigation is necessary to determine accurate neutron dose based on the precise energy spectra.The 5th International Symposium on Radiation Safety and Detection Technology (ISORD-5