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Ay 191 Experiment Development of Hard X-ray Imaging Detectors J. Hong, B. Allen and J. Grindlay. Hard X-rays (~5-600 keV) are direct probes of black holes : GRBs, AGNs, Stellar BHs, etc.
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Ay 191 Experiment Development of Hard X-ray Imaging Detectors J. Hong, B. Allen and J. Grindlay • Hard X-rays (~5-600 keV) are direct probes of black holes: GRBs, AGNs, Stellar BHs, etc. • Direct imaging using mirrors is possible only for narrow FoV (<~1º) and low energies (<~100 keV) => coded-aperture telescope • Harvard balloon-borne telescope (ProtoEXIST) is a coded-aperture telescope for wide-field (~10ºx10º) hard X-ray imaging. • ProtoEXIST is a prototype platform for development of EXIST (Energetic X-ray Imaging Survey Telescope), to probe the early Universe using high redshift GRBs and survey BHs on all scale.
Coded-Aperture Hard X-ray Imaging Telescope Decoding Shadowgram allows for wide-field imaging in hard X-ray band. Position-sensitive hard X-ray detectors needed: Use Cd-Zn-Te (CZT) arrays.
Cd-Zn-Te (CZT) Hard X-ray Imaging Detector CZT Detectors 8 x 8 pixels on each 20 x 20mm CZT crystal (pixels on bottom) Schematic CZT detector: Electrons drift to anode Under ~600V bias
ProtoEXIST • Demonstrate the technology for large array CZT detectors with small pixels covering 5 – 600 keV • ProtoEXIST1 = 512 cm2 (2.5 mm pixel) • ProtoEXIST2 & 3 = 512 cm2 (0.6 mm pixel) • EXIST ~ 4.5 m2 (0.6 mm pixel) • Identify the optimal shielding configuration • Demonstrate continuous scanning coded-aperture imaging technique
Ay191 experiments • Learn about • -Hard X-ray sources in the sky: Black holes … • -Hard X-ray Imaging: Coded-aperture telescopes • -Hard X-ray Detectors: CdZnTe detector • Experiments to be conducted (at CfA ProtoEXIST lab, B-105): • -Calibrating new CZT imager with 60, 122, 356 keV sources • -Measuring spatial and spectral resolution over detector • -Sensitivity to multi-pixel (split) events • -Cooling test (to ~0 – 5°C) with CZT modules