The development of the high energy particle detector onboard the SELENE spacecraft

The PS (particle spectroscopy) sensor, that will be onboard the SELENE spacecraft for the first Japanese lunar mission to be launched in 2005, will measure the high energy cosmic ray particles to measure a radiation environment around the moon for human activities in the future and to study their acceleration and propagation in the solar system. The PS sensor consists of 4 detectors: high energy isotope detector (HID), low energy particle detector for heavy ions (LPD-HE), low energy particle detector for proton (LPD-p) and low energy particle detector for electron (LPD-e). These are Si stuck detectors using the ΔE × E method that cover the energy range from 100 keV to 60 MeV for proton, from 30 keV to a few MeV for electron and from 3 MeV/n to 400 MeV/n for heavy ions, respectively. We use a new type B⁺ doped Si(Li) detector of which thickness is from 1 to 6 mm with high energy resolution for each sensor. We can identify the isotopes for heavy ions from He to Xe by the PS sensor.