  X-ray experiments in the intermediate energy range (1-50 keV) are carried out
at the Indian Centre for Space Physics (ICSP), Kolkata for space application.
The purpose is to carry out developmental studies of space instruments to
observe energetic phenomena from compact objects (black hole and compact stars)
and active stars and their testing and evaluation. The testing/evaluation setup
primarily consists of an X-ray generator, various X-ray imaging masks, an X-ray
imager (CMOS) and an X-ray spectrometer (Si-PIN photo-diode). The X-ray
generator (Mo target) operates in 1-50 kV anode voltage, and 1-30 mA beam
current. A 45 feet long shielded collimator is used to collimate the beam which
leads to the detector chamber having a 30 arc-sec angular diameter. Two types
of imaging masks are used - conventional Coded Aperture Masks (CAM) and
Tungsten Fresnel half-period zone-plates (ZPs) having angular resolutions of a
few tens of arc-sec. The Moire fringe pattern produced by the composite shadows
of two ZPs is inverse Fourier transformed to obtain the X-ray source
distribution. CAMs are advantageous but the resolution obtained is limited by
their smallest pixel size. Our setup has been extensively used in testing and
evaluation of RT-2 payloads which have been launched recentlya (January 30,
2009). More experiments for improving imaging techniques are being designed and
tested.
