Modulated X-ray source developed for telescope calibration in space

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Photonis has announced an agreement with the Netherlands Institute for Space Research (SRON) to create a new type of X-ray source for the calibration of a new spectrometer on the Japanese ASTRO-H telescope, which is scheduled to be launched in 2014. The telescope is designed to observe cosmic X-rays from supernovas, black holes and galaxy clusters. Photonis is designing 21 units for the modulated X-ray source (MXS), an integral component of the mission.

The ASTRO-H telescope will use cosmic X-ray observations to study collapsing material in the vicinity of high-energy space events, such as black holes and supernova explosions. The telescope will also provide maps and accurate spectra profiles of galaxies and supernova remains. The soft X-ray spectrometer will be built by the Japanese space agency (JAXA/ISAS) in collaboration with NASA/GSFC, with contributions from agencies in Europe.

High intensity cosmic X-rays can overload the sensitive detector in the spectrometer, and micro-meteorites could potentially damage the detector. The soft X-ray spectrometer (SXS) is therefore being designed with a filter wheel which can modulate the intensity of the X-rays reaching the spectrometer, thus enhancing the quality of the observations. The filters will also be used to protect the spectrometer against micro-meteorite impacts.

The unique energy-separating capacity of the spectrometer requires a continuous correction for small fluctuations in the instrument’s energy scale in order to remain calibrated. This can be done effectively with a new type of on-board X-ray source. This local calibration source, with precisely known spectral lines, can be switched on and off as required in order to avoid interfering with the detection of celestial X-rays. Photonis' MXS device will act as the telescope's calibration source, mounted on the filter wheel housing that SRON is developing in collaboration with the University of Geneva.