編碼板在康卜吞成像光譜儀的應用

Application of Coded Mask on The Compton Spectrometer and Imager (COSI)

商婕柔(Jie-Rou Shang)

指導教授 ： 張祥光

國立清華大學/理學院/天文研究所/碩士(2014年)

摘要

The Compton Spectrometer and Imager (COSI) is a soft γ-ray (0.2 ~ 10
MeV) telescope with twelve germanium detectors (GeDs), which are designed to
detect the cosmic γ-ray photons by using the Compton scattering technique to
locate the incident photons. A coded mask technique is planned to be applied on
this instrument, so that the incoming non-scattered photons below 200 keV can
be imaged instead of being excluded in the existing Compton imaging approach.
The imaging capability of COSI is then expected to extend to the hard X-ray
band (40-100 keV) to enable more possibilities on scientific purposes.
With a basic mask pattern designed for COSI, which is a 33×31 pixels array
with a pixel size of 2× 2 mm2 (the spatial resolution of the GeDs is 2 mm), we set up a data reduction pipeline for the coded mask pattern and tested the an-
alytic method by performing Monte-Carlo simulations to get the instrumental
parameters and found the best-performed mask geometry and material. The
effects from the Caroli-factor and pixel shuffling were considered in the simula-
tions. From the simulation results, we decided to use Tin (Sn) which absorbs
effectively below 100 keV but is well transmitted at high energy range, as the
mask material.

關鍵字

Coded mask ； COSI

參考文獻

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