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M. Polsen (IGPP, UC Riverside), A. Akyüz (Physics Dept., University of Cukurova, Adana, Turkey), D. Bhattacharya, T. J. O'Neill (IGPP, UC Riverside), J. Samimi (Physics Dept., Sharif Technical University, Tehran, Iran), A. D. Zych (IGPP, UC Riverside)
The point source sensitivities of low- and medium-energy gamma ray telescopes are limited by the relatively high levels of background and low signal-to-noise ratios. This is particularly true for Compton telescopes. The TIGRE instrument with Compton recoil electron tracking is being developed at UC Riverside to address this problem. Electron tracking along with improved energy and spatial resolutions combine to narrow the point-spread-function and improve sensitivity. The results of our Monte Carlo simulations with gamma-ray background and discrete source events will be presented to compare the relative sensitivities for events with electron tracking and conventional non-tracked Compton events. Three sensitivity methods are considered to estimate the statistical significance for point source detection. These include i) the standard on/off-source method and the likelihood ratio test method with both ii) radial and iii) two-dimensional PSFs. The point source sensitivities with electron tracking are improved by a factor 1.4, 2.5 and 4.0 with these three methods. A factor of 4 improvement with electron tracking implies a reduction in background by a factor of 16 and a corresponding reduction in observing time for minimal source detection. The TIGRE concept is a potential candidate for a future Advanced Compton Telescope space mission.
Work supported by NASA Grants NAG5-5116 and NNG04WC14G
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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.