Photonis Netherlands has reached an agreement with the Netherlands Institute for Space Research (SRON) to create a new type of x-ray source for the calibration of a spectrometer on the Japanese Astro-H telescope. The telescope, which is scheduled to be launched in 2014, is designed to observe cosmic x-rays. Astro-H will use cosmic x-ray observations to study collapsing material near high-energy space events, such as black holes and supernova explosions. It will also provide maps and accurate spectra profiles of galaxies and supernova remains. The Soft X-ray Spectrometer (SXS) will be built by the Japanese space agency in collaboration with NASA’s Goddard Space Flight Center, with contributions from agencies in Europe. Photonis is designing 21 of the test instruments, dubbed the Modulated X-Ray Source (MXS). High-intensity cosmic x-ray sources can overload the sensitive detector in the spectrometer while micrometeorites potentially can damage the detector. The SXS is being designed with a filter wheel that can modulate the intensity of the x-rays reaching the spectrometer and thus enhance the quality of the observations. The filters can also be used to protect the spectrometer against micrometeorite impacts. The unique energy-separating capacity of the spectrometer requires a continuous correction for small fluctuations in the instrument’s energy scale to keep this scale 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 calibrations are needed so calibration x-rays are not confused with celestial x-rays. The MXS, acting as the calibration source, will be mounted on the filter wheel housing that SRON is developing in collaboration with the University of Geneva for the SXS. For more information, visit: www.photonis.com