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A. R. Rao ¹, D. Bhattacharya ², V. B. Bhalerao ², S. V. Vadawale ³, S. Sreekumar ⁴

Affiliations
1 Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, IN
2 Inter-University Centre for Astronomy and Astrophysics, Pune 411 007, IN
3 Physical Research Laboratory, Ahmedabad 380 009, IN
4 Vikram Sarabhai Space Centre, Thiruvananthapuram 695 024, IN

Abstract

The AstroSat satellite is designed to make multi-waveband observations of astronomical sources and the Cadmium-Zinc-Telluride Imager (CZTI) instrument of AstroSat covers the hard X-ray band. CZTI has a large area position-sensitive hard X-ray detector equipped with a coded aperture mask, thus enabling simultaneous background measurements. Ability to record simultaneous detection of ionizing interactions in multiple detector elements is a special feature of the instrument, and this is exploited to provide polarization information in the 100-380 keV region. CZTI provides sensitive spectroscopic measurements in the 20-100 keV region, and acts as an all-sky hard X-ray monitor and polarimeter above 100 keV. During the first year of operation, CZTI has recorded several gamma-ray bursts, measured the phase-resolved hard X-ray polarization of the Crab pulsar, and the hard X-ray spectra of many bright galactic X-ray binaries. The excellent timing capability of the instrument has been demonstrated with simultaneous observation of the Crab pulsar with radio telescopes like Gaint Metrewave Radio Telescope and Ooty Radio Telescope.

Keywords

All-Sky Hard X-Ray Monitor, Gamma-Ray Bursts, Neutron Stars, X-Ray Polarization.

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M. Shanmugam ¹, S. V. Vadawale ¹, Arpit R. Patel ¹, Hitesh Kumar Adalaja ¹, N. P. S. Mithun ¹, Tinkal Ladiya ¹, Shiv Kumar Goyal ¹, Neeraj K. Tiwari ¹, Nishant Singh ¹, Sushil Kumar ¹, Deepak Kumar Painkra ¹, Y. B. Acharya ¹, Anil Bhardwaj ¹, A. K. Hait ², A. Patinge ², Abinandhan Kapoor ³, H. N. Suresh Kumar ³, Neeraj Satya ³, Gaurav Saxena ⁴, Kalpana Arvind ⁴

Affiliations
1 Physical Research Laboratory, Ahmedabad 380 009, IN
2 Space Applications Centre, Ahmedabad 380 015, IN
3 U. R. Rao Satellite Centre, Bengaluru 560 017, IN
4 Laboratory for Electro Optics Systems, Bengaluru 560 058, IN

Abstract

Solar X-ray Monitor (XSM) is one of the scientific instruments onboard Chandrayaan-2 orbiter. The XSM along with instrument CLASS (Chandra’s Large Area soft X-ray Spectrometer) comprise the remote X-ray fluorescence spectroscopy experiment of Chandrayaan- 2 mission with an objective to determine the elemental composition of the lunar surface on a global scale. XSM instrument will measure the solar X-rays in the energy range of 1–15 keV using state-of-the-art silicon drift detector. The flight model of the XSM payload has been designed, realized and characterized for various operating parameters. XSM provides energy resolution of ~180 eV at 5.9 keV with high time cadence of one second. The X-ray spectra of the Sun observed with XSM will also contribute to the study of solar corona. The detailed description and the performance characteristics of the XSM instrument are presented in this article.

Keywords

Lunar X-Rays, Silicon Drift Detector, Solar X-Rays, X-Ray Spectrometer.

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M. Shanmugam ¹, S. V. Vadawale ¹, Arpit R. Patel ¹, N. P. S. Mithun ¹, Hitesh Kumar Adalaja ¹, Tinkal Ladiya ¹, Shiv Kumar Goyal ¹, Neeraj K. Tiwari ¹, Nishant Singh ¹, Sushil Kumar ¹, Deepak Kumar Painkra ¹, A. K. Hait ², A. Patinge ², Abhishek Kumar ³, Saleem Basha ³, Vivek R. Subramanian ³, R. G. Venkatesh ³, D. B. Prashant ³, Sonal Navle ³, Y. B. Acharya ¹, S. V. S. Murty ¹, Anil Bhardwaj ¹

Affiliations
1 Physical Research Laboratory, Ahmedabad 380 009, IN
2 Space Applications Centre, Ahmedabad 380 015, IN
3 U.R. Rao Satellite Centre, Bengaluru 560 017, IN

Abstract

Alpha Particle X-ray Spectrometer (APXS) is one of the two scientific experiments on Chandrayaan-2 rover named as Pragyan. The primary scientific objective of APXS is to determine the elemental composition of the lunar surface in the surrounding regions of the landing site. This will be achieved by employing the technique of X-ray fluorescence (XRF) spectroscopy using in situ excitation source ²⁴⁴Cm emitting both X-rays and alpha particles. These radiations excite characteristic X-rays of the elements by the processes of particle induced X-ray emission and XRF. The characteristic X-rays are detected by the ‘state-of-the-art’ X-ray detector known as Silicon Drift Detector, which provides high energy resolution, as well as high efficiency in the energy range of 1–25 keV. This enables APXS to detect all major rock forming elements such as, Na, Mg, Al, Si, Ca, Ti and Fe. The flight model of the APXS payload has been completed and tested for various instrument parameters. The APXS provides energy resolution of ~135 eV at 5. 9keV for the detector operating temperature of about –35°C. The design details and the performance measurement of APXS are presented in this paper.

Keywords

Alpha Particle X-Ray Spectrometer, CSPA, Silicon Drift Detector, X-Ray Spectrometer.

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