A thin dead-layer avalanche photodiode enables low energy ion measurement for space plasmas
Abstract
We report on the performance of a thin dead-layer Avalanche Photodiode (APD) targeting medium-energy ions. This light and low-power device provides high-resolution, proportional measurements even at room temperature, with reliable and stable efficiency in the medium-energy range (from 1 keV to 100 keV in the total energy of the particle) where there is a gap in the coverage of existing devices. We characterized the device response against 7 different ion species of H+, He+, N+, He+, He2+, Ar+, and Ar2+. The pulse height distribution of the APD signals shows a significant peak with energies >2.5 keV/q for H+, and >3.4 keV/q for He+. The measured noise level is 1.1 keV in silicon. The response linearity was notably excellent for H+ and He+ with an energy resolution of ~15% at 55 keV/q. The dead-layer thickness was measured to be as thin as 340Å by scanning the incidence angle of the 58-keV H+ beam. Considering the whole active layer thickness of ~150μm, the maximum detectable energy was calculated to be 4 MeV/q (H+) or higher depending on ion species. This device is appropriate for many ion measurements in the field of space plasma physics such as in detectors in high-energy ion telescopes, medium-energy detectors with electrostatic analyzers or magnetic deflectors, and/or measurements of ions using time of flight. Thus, thin dead-layer APDs are useful in measuring a variety of scientific targets including the solar wind, CME's, IP shocks, and interplanetary space phenomena.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFMSH33B1495O
- Keywords:
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- 2794 MAGNETOSPHERIC PHYSICS / Instruments and techniques;
- 7594 SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY / Instruments and techniques;
- 7894 SPACE PLASMA PHYSICS / Instruments and techniques;
- 9805 GENERAL OR MISCELLANEOUS / Instruments useful in three or more fields