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Development of Large-area Lithium-drifted Silicon Detectors for the GAPS Experiment
Name
1812.07255.pdf
Description
Accepted version
Size
363.08 KB
Format
Adobe PDF
Checksum (MD5)
73e88adb998ed368b2dd7113f62a545d
Author(s)
Kozai, M
Fuke, H
Yamada, M
Erjavec, T
Hailey, CJ
Kato, C
Madden, N
Munakata, K
Perez, K
Rogers, F
Journal
2018 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2018 - Proceedings
Publisher
Institute of Electrical and Electronics Engineers (IEEE)
Version
Author's final manuscript
Abstract
© 2018 IEEE. We have developed large-area lithium-drifted silicon (Si(Li)) detectors to meet the unique requirements of the General Antiparticle Spectrometer (GAPS) experiment. GAPS is an Antarctic balloon-borne mission scheduled for the first flight in late 2020. The GAPS experiment aims to survey low-energy cosmic-ray antinuclei, particularly antideuterons, which are recognized as essentially background-free signals from dark matter annihilation or decay. The GAPS Si(Li) detector design is a thickness of 2.5 mm, diameter of 10 cm and 8 readout strips. The energy resolution of <4 keV (FWHM) for 20 to 100 keV X-rays at temperature of -35 to -45 C, far above the liquid nitrogen temperatures frequently used to achieve fine energy resolution, is required. We developed a high-quality Si crystal and Li-evaporation, diffusion and drift methods to form a uniform Li-drifted layer. Guard ring structure and optimal etching of the surface are confirmed to suppress the leakage current, which is a main source of noise. We found a thin un-drifted layer retained on the p-side effectively suppresses the leakage current. By these developments, we succeeded in developing the GAPS Si(Li) detector. As the ultimate GAPS instrument will require >1000 10-cm diameter Si(Li) detectors to achieve high sensitivity to rare antideuteron events, high-yield production is also a key factor for the success of the GAPS mission.
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike
Persistent DSpace Link
DOI of Published Version
10.1109/NSSMIC.2018.8824342
