The C1XS X-ray Spectrometer on Chandrayaan-1
- Paper number
IAC-08.A3.2.A9
- Author
Prof. Manuel Grande, Aberystwyth University, United Kingdom
- Coauthor
Dr. Ian Crawford, Birkbeck College London, United Kingdom
- Coauthor
Mr. Brian Maddison, Rutherford Appleton Laboratory, United Kingdom
- Coauthor
Dr. David Smith, Brunel University, United Kingdom
- Coauthor
Mr. Barry kellett, Rutherford Appleton Laboratory, United Kingdom
- Coauthor
Dr. P Sreekumar, ISRO Satellite Centre (ISAC), India
- Coauthor
Dr. Juhani Huovelin, Helsinki University Observatory, Finland
- Coauthor
Mr. Chris Howe, Rutherford Appleton Laboratory, United Kingdom
- Coauthor
Dr. Katie Joy, Birkbeck College London, United Kingdom
- Year
2008
- Abstract
The Chandrayaan-1 X-ray Spectrometer (C1XS) is a compact X-ray spectrometer for the Indian Space Research Organisation (ISRO) Chandrayaan-1 lunar mission, launching mid 2008. It exploits heritage from the D-CIXS instrument on ESA’s SMART1 mission. By comparison with SMART-1, Chandrayaan-1 is intended as a science rather than a technology mission, leading to far more favourable conditions for science measurements. C1XS is designed to measure absolute and relative abundances of major rock-forming elements (principally Mg, Al, Si, Ti, Ca and Fe). The CIXS instrument hardware is built by an international team led from the Rutherford Appleton Laboratory. The Principal Investigator is Prof M. Grande at the Aberystwyth University, and there is also a major science and design contribution from ISAC, ISRO, Bangalore, India; CESR, Toulouse, France provide amplifiers. The Science team is led by Dr I A Crawford of Birkbeck College London. In order to record the incident solar X-ray flux at the Moon, a good measure of which is essential to derive absolute lunar elemental surface abundances, CIXS carries an X-ray Solar Monitor (XSM) provided by the University of Helsinki, Finland. The baseline design consists of 24 nadir pointing Swept Charge Device detectors, which provide high detection efficiency in the 1 to 7 keV range, which contains the X-ray fluorescence lines of interest. Micro-machined collimators provide a 14 degree FWHM FOV, equivalent to 25 km from 100km altitude. A deployable door protects the instrument during launch and cruise, and also provides a Fe55 calibration X-ray sources for each of the detectors. Additional refinements to the electronics, onboard software and thermal design greatly increase detector stability and signal to noise ratio compared to D-CIXS. This will result in a significantly improved energy resolution which should therefore be better than 200eV throughout the lifetime of the mission. C1XS will arrive at the Moon in the run up to the maximum of the solar cycle, and the high incident X-ray flux coupled to an orbit optimized for science, means that we will obtain composition data accurate to better than 10
- Abstract document
- Manuscript document
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