1. 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 ( 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.

2. 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.

3. 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

4. ProtoEXIST1 Detector Module (2.5mm pixel)

5. ProtoEXIST Demonstrate the technology for large array CZT detectors with small pixels covering 5 – 600 keV ProtoEXIST1 = 512 cm 2 (2.5 mm pixel) ProtoEXIST2 & 3 = 512 cm 2 (0.6 mm pixel) EXIST ~ 4.5 m 2 (0.6 mm pixel) Identify the optimal shielding configuration Demonstrate continuous scanning coded- aperture imaging technique

6. 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 Ay191 experiments