First Author: Contos, A. R.,

Co-Authors: T. A. Fritz, J. D. Sullivan, J. B. Blake, W. B. Cottingame, and W. A. Kolasinski,

Title: The High Sensitivity Telescope (HIST) Onboard the POLAR Satellite,

Reference: Nuclear Instruments and Methods, 2001 [being revised/ referee comments received] [available on line at:http://spacedata.bu.edu/papers/hist_description.html].

Reference Type: Submitted Journal

CEPPAD: true

CAMMICE: false

RAPID: false

Abstract: 
The POLAR spacecraft was launched February 24, 1996. One of the instruments aboard POLAR is the High Sensitivity Telescope (HIST) which is part of the Comprehensive Energetic Particle and Pitch Angle Distribution (CEPPAD) experiment. The primary objective of CEPPAD/HIST is to provide uncontaminated measurements of the fluxes of 350 keV to 10 MeV electrons in the Earth's magnetosphere. Protons from 3.25 to ~100 MeV are also measured. <P> This work uses a full Monte Carlo simulation of the HIST, including modeled geometry and electronics to derive the instrument response to electrons up to 12 MeV and protons to 120 MeV. These simulations use a flat, continuous particle energy spectrum as a normally incident beam and are validated by comparisons with pre-launch beam calibrations. On-orbit characteristics and efficiencies are determined using a realistic power law energy spectrum. Since exhaustive calibrations can be prohibitively expensive, such simulations augment and complement calibrations. This validated simulation tool is used to compute the response of HIST in all operating modes and in turn optimize the instrument. The flight data are corrected by the computed response to give clean spectra which the provide the basis for all subsequent analysis.