Gamma-ray detection efficiency of the microchannel plate installed as an ion detector in the low energy particle instrument onboard the GEOTAIL satellite
Abstract
A microchannel plate (MCP) assembly has been used as an ion detector in the low energy particle (LEP) instrument onboard the magnetospheric satellite GEOTAIL. Recently the MCP assembly has detected gamma rays emitted from an astronomical object and has been shown to provide unique information of gamma rays if they are intense enough. However, the detection efficiency for gamma rays was not measured before launch, and therefore we could not analyze the LEP data quantitatively. In this article, we report the gamma-ray detection efficiency of the MCP assembly. The measured efficiencies are 1.29%+/-0.71% and 0.21%+/-0.14% for normal incidence 60 and 662 keV gamma rays, respectively. The incident angle dependence is also presented. Our calibration is crucial to study high energy astrophysical phenomena by using the LEP.
- Publication:
-
Review of Scientific Instruments
- Pub Date:
- March 2007
- DOI:
- 10.1063/1.2713440
- Bibcode:
- 2007RScI...78c4501T
- Keywords:
-
- 94.80.+g;
- 07.85.Fv;
- 29.40.Gx;
- 06.20.fb;
- Instrumentation for space plasma physics ionosphere and magnetosphere;
- X- and gamma-ray sources mirrors gratings and detectors;
- Tracking and position-sensitive detectors;
- Standards and calibration