Large area silicon detectors for detecting heavy particles in cosmic rays

Large silicon detectors with good uniformity in thickness, made of 6-inch Si wafers, were developed as a heavy particle detector for measurement of cosmic ray particles. The Si detectors with an effective area of 92 mm x 92 mm and 320 μm in thickness were fully depleted. Basic performance was measured using a standard α-particle source and a high energy argon beam with 600 MeV/n. Non-uniformity of the detector thickness was less than 0.7% in full width half maximum (FWHM). The detectors are found to be good enough to use for the identification of nuclear charge of heavy ions, as well as of their mass separation. (author)