Ay 191 Experiment Development of Hard X-ray Imaging Detectors

J. Hong and J. Grindlay

• Hard X-rays (~10-600 keV) are direct probes of black holes: GRBs, AGNs, Stellar BHs, etc.

• Direct imaging possible only for narrow FoV (<~0.1º) and only for low energies (<~100 keV) => coded-aperture telescope

• Harvard balloon-borne telescope (ProtoEXIST) is a coded-aperture telescope for wide-field (~20ºx20º) hard X-ray imaging and is a prototype platform for development of the

scanning telescope needed for a major NASA mission,

EXIST, to conduct a very sensitive all-sky survey for BHs

Coded-Aperture Hard X-ray Imaging Telescope

Decoding Shadowgram allows wide-field imaging.

Position-sensitive hard X-raydetectors 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 20mmCZT crystal (pixels on bottom)

Schematic CZT detector:

Electrons drift to anode

Under ~700V bias

CZT detectors: prototype lab arrayCZT detectors: prototype lab array

4cm x 8cm Detector Crystal Array (DCA)

ProtoEXIST detector array

Energetic X-ray Imaging Telescope Experiment (ProtoEXIST)with 1000 cm2 CZT detectors

Balloon-borne ProtoEXIST Telescope

• 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 -10°C) with CZT modules-Design considerations for ProtoEXIST balloon-

telescope

Ay191 experiments