Calibration of the Compton Spectrometer and Imager in preparation for the 2014 balloon campaign

C. A. Kierans, S. E. Boggs, A. Lowell, J. Tomsick, A. Zoglauer, M. Amman, J. L. Chiu, H. K. Chang, C. H. Lin, P. Jean, P. Von Ballmoos, C. Y. Yang, J. R. Shang, C. H. Tseng, Y. Chou, Y. H. Chang

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

15 Scopus citations


The Compton Spectrometer and Imager (COSI) is a balloon-borne soft gamma-ray (0.2-5 MeV) telescope designed to perform wide-field imaging, high-resolution spectroscopy, and novel polarization measurements of astrophysical sources. COSI employs a compact Compton telescope design, utilizing 12 cross-strip germanium detectors to track the path of incident photons, where position and energy deposits from Compton interactions allow for a reconstruction of the source position in the sky, an inherent measure of the linear polarization, and significant background reduction. The instrument has recently been rebuilt with an updated and optimized design; the polarization sensitivity and effective area have increased due to a change in detector configuration, and the new lightweight gondola is suited to fly on ultra-long duration flights with the addition of a mechanical cryocooler system. COSI is planning to launch from the Long Duration Balloon site at McMurdo Station, Antarctica, in December 2014, where our primary science goal will be to measure gamma-ray burst (GRB) polarization. In preparation for the 2014 campaign, we have performed preliminary calibrations of the energy and 3-D position of interactions within the detector, and simulations of the angular resolution and detector efficiency of the integrated instrument. In this paper we will present the science goals for the 2014 COSI campaign and the techniques and results of the preliminary calibrations.

Original languageEnglish
Title of host publicationSpace Telescopes and Instrumentation 2014
Subtitle of host publicationUltraviolet to Gamma Ray
EditorsTadayuki Takahashi, Jan-Willem A. den Herder, Mark Bautz
ISBN (Electronic)9780819496126
StatePublished - 2014
EventSpace Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray - Montreal, Canada
Duration: 22 Jun 201426 Jun 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSpace Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray


  • Compton telescope
  • balloon payloads
  • gamma-ray polarization
  • gamma-ray spectroscopy
  • germanium detectors


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