The RGS instrument is the X–ray spectrometer on board the XMM-Newton satellite, launched December 1999, and still fully operational. It consists of a reflection grating to disperse the incoming X–rays and a CCD camera as detector. In the past fifteen years a lot of experience has been gained in operating and calibrating this instrument. In this presentation we report on the calibration methods and status, new instrumental modes and detector performance, which were acquired and developed based on the in-flight experiences with the instrument. Selecting the proper operating modes, combined with careful data processing based on target characteristics and science goals, allows detection of weak spectral features, despite slowly degrading detectors due to radiation damage and contamination. At present the instrument has excellent health status and performance, and will be one of the few major instruments for X–ray spectroscopy in the coming years, until supplemented by new missions like ASTRO-H and, in particular, Athena.
On December 10th 2004 the XMM-Newton observatory celebrated its 5th year in orbit. Since the beginning of the mission steady health and contamination monitoring has been performed by the XMM-Newton SOC and the instrument teams. Main targets of the monitoring, using scientific data for all instruments on board, are the behaviour of the Charge Transfer Efficiency, the gain, the effective area and the bad, hot and noisy pixels. The monitoring is performed by combination of calibration observations using internal radioactive calibration sources with observations of astronomical targets. In addition a set of housekeeping parameters is continuously monitored reflecting the health situation of the instruments from an engineering point of view. We show trend behaviour over the 5 years especially in combination with events like solar flares and other events affecting the performance of the instruments.
SciSim is a complete simulator for the XMM-Newton X-ray observatory. Its purpose is to generate realistic simulated science data for a wide range of observational scenarios. SciSim is comprised of a number of separate simulators for the various components of the telescope and instruments on the XMM-Newton satellite. These act behind a Cosmic Simulator (CSIM), which allows the user to create source data, either through extracting sources from a catalogue, placing sources manually or simulating the sky. A ray generator (GSIM) generates data from the source for ray tracing, which is then fed down a pipeline formed by the spacecraft and instrument simulators. A fully configurable detailed physical description of all components, spacecraft, mirrors, gratings and CCD cameras, together with their interactions with X-rays, provide the means to perform deep simulation studies. The output of the simulations can be converted into a format compatible with the XMM-Newton Science Analysis System, and thus may be reduced in an identical manner to a real sky observation.
The aim of the system is multiple: to develop observation strategies, to understand calibration effects and eventual aging / malfunction of the different components, to optimize analysis tools and algorithms and as an astrometry aided tool, that can be used during mission planning phases.
The ESA mission XMM-Newton was launched in 1999. Two of the three X-ray telescopes include reflection grating spectrometers (RGS). These spectrometers consist of a set of reflection gratings and an array of 9 back-illuminated CCDs, optimized for the soft energy response (0.35 - 2 keV). These CCDs can be passively cooled between -80 and -120°C. After a short description of the instrument we compare the performance of these CCD detectors with the pre-flight expectations and discuss the effect of some design choices on the in-flight performance. We concentrate on the effects of radiation damage due to cosmic rays and coronal mass ejections of the Sun, including flickering pixels and the effects of cooling the detector to -110°C. We also address the stability of the detector response including the assessment of possible contamination of these cooled detectors.
XMM-Newton was launched in December 1999 and science operations started in March 2000. Following two years of very successful operations, a report on the instrument performance and a selection of exciting new results are presented. Behind two of the three telescopes of XMM-Newton Reflection Grating Spectrometers (RGS) are placed. Each spectrometer consists of an array of reflection gratings and a set of back illuminated CCDs. They cover the wavelength band between 6 and 38 Angstromwith a resolution varying between 100 and 600 (E/DE) and a maximum effective area of 140 cm2 for the two spectrometers combined. The selected wavelength band covers the K-shell transitions of C, N, O, Ne, Mg and Si as well as the L- and M-shell transitions of Fe. After a short introduction to the instrument design, the in-orbit performance is given. This includes the line spread function, the wavelength scale and the effective area including their stability during the more than 2 years of operations. Following this a number of key scientific results are briefly addressed, illustrating the power of the RGS instrument in combination with the other instruments on-board of XMM-Newton as well as the wealth of information which is obtained as the RGS instruments operate continuously.
A calibration facility simulating the optical and cryogenic environment of the Infrared Space Observatory (ISO) satellite has been built for characterizing the ISO photometer (ISOPHOT). This facility uses a commercially calibrated 900-K blackbody radiation source and optics at room temperature to provide an f/15 beam to the instrument, which is contained in a LHe cryostat. The low-level infrared flux levels of the ISO are obtained by using a light-sealed instrument chamber and cold attenuation filters. The infrared flux can be calculated using the known blackbody emission and the cold calibrated transmission spectra of the filters. The calibration facility further provides a scanning mechanism, a light modulator, and filters for polarization measurements and wavelength calibrations of the ISOPHOT spectrometer channels. Electrical support equipment for the instrument operation and software for data archiving and analysis have been customized for this project. The test program comprised a standardized acceptance test for the entire instrument and special tests addressing individual instrument properties. The data obtained contain the photometric sensitivities of ISOPHOT, optimized instrument settings, reference data for the integrated system tests, and inputs for the ongoing mission planning.
A calibration facility simulating the optical and cryogenic environment of the ISO satellite has been built for characterizing the ISOPHOT instrument. This facility uses a commercially calibrated, 900 K--blackbody radiation source and an optics at room temperature to provide an f/15 beam to the instrument which is contained in a LHe-cryostat. The low level infrared flux levels of ISO are obtained by use of a light sealed instrument chamber and cold attenuation filters. The infrared flux can be calculated using the known blackbody emission and the cold calibrated transmission spectra of the filters. The calibration facility further provides a scanning mechanism, a light modulator and filters for polarization measurements and wavelength calibrations of the ISOPHOT spectrometer channels. Electrical support equipment for the instrument operation and software for data archiving and analysis have been customized for this project. The test program comprised a standardized acceptance test for the entire instrument and special tests addressing individual instrument properties. The data obtained contain the photometric sensitivities of ISOPHOT, optimized instrument settings, reference data for the integrated system tests and inputs for the ongoing mission planning.