CZT Imager for ASTROSAT

CONFIGURATION

CZT Module

256 ampli. (ASIC)

1 microsec;Isolation; fast ADC;

FPGA

LabView;Analysis

Imarad CZT + Ideas ASIC

Open issues… (a `to do’ list:) Space qualification of components:

CZT module;

Opto-isolator;

CPM (CsI + photo-diode) CZT procurement Establishing collimator/ CAM methodology Background modeling CsI/ PMT qualification Power/ weight

CZT procurement… Next 4 months: Structural analysis of a module Replicate electronics (Detector board; amplifier; FE electronics)

Temperature test Procure different configuration modules (same ASIC; different detectors) Generate qualification document 5 – 8 months Proceed with qualification and choose Generate RFP 9 – 12 months Procure additional modules for lab model 13 – 18 months Procure flight modules

Background Reduction

New “Phoswich” combination ….

Expected Count rates (per second; per quadrant)

Diffuse Cosmic backgroundCalibration source

10100

Crab Nebula (5 keV threshold) 200

Crab Nebula (10 keV threshold) 100

Veto triggered events 250

Maximum expected event rate 1000

Design considerations

Active Compton Background rejection Simple shield – minimize mass Collimator to reduce DCXRB Quadrant-wise Cooling requirements

Major components

CZT detectors CsI(Tl) – anticoincidence Collimator/ Coded Aperture Mask Alha-tagged source Data handling system

Specifications…Area 1024 cm 2 (+/- 20%)

Pixels 16384

Pixel size 2.5 mm X 2.5 mm (5 mm thick)

Read-out ASIC based (128 chips of 128 channels)

Imaging method Coded Aperture Mask (CAM)

Field of View 17 X 17 deg2 (CAM) - > 100 keV5 X 5 (25 – 100 keV) (20 – 40 deg 2 )

1 X 1 (5 – 25 keV) (1 – 5 deg 2 )

Angular resolution 8 arcmin (21 arcmin geometric) (5 – 40 ‘)

Energy resolution 3% @ 100 keV (< 5 %)

Energy range 5 – 100 keV (LLD: < 10; ULD: 80-120

Up to 1 MeV (Photometric)

Sensitivity 0.5 mCrab (5 sig; 10 4 s) (< 1 mC)

CZT Detector CZT Electronics

Package Code AS-CZ-DT-01 AS-CZ-EL-01

Package dimensions (excluding lugs)

490 X 490 X 700 205 X 224 X 182

Mounting lug 16 M6 screws 6 M4 screws

Mounting requirement Thermal isolation

None

Weight (kg) 70* 3

Alignment requirement + 0.05 o None

Power (W) 50 2.5

Overall envelope 550 X 550 X 750 220 X 260 X 200

FOV 17 o X 17 o None

Heritage None GXHE-10 (GSAT-2)

Number of connectors 24 12

Number of el. cards 28 9