Accelerator beam experiments of a prototype cosmic ray heavy ion telescope

A Heavy Ion cosmic ray Telescope (HIT) has been scheduled to be launched into the synchronous orbit in 1993 aiming to observe elemental and isotopic composition of solar energetic particles and galactic cosmic rays. In this paper, we report the results of accelerator beam experiments of a prototype model of HIT. The telescope consists of two dimensional Position Sensitive Detectors (PSD5) and energy loss detectors (PIN type and Li-drifted type). The mass resolution was 1.1 amu in FWHM for 110 MeV/n pure iron (⁵⁶Fe) beam. By exposing HIT to beams consisting of various nuclides produced by the projectile fragmentation process in a reaction induced by ⁵⁶Fe beam, we confirmed that the secondary elements from ₁₆S to ₂₅Mn were clearly separated and that also the isotopes were separated for each elements lighter than ₂₂Ti. The observed mass resolution was 0.57 amu, 0.66 amu and 0.82 amu in FWHM for ₁₈Ar, ₂₀Ca and ₂₂Ti, respectively. We can conclude that the HIT has good prospects of enough ability for our current purpose in space observation.