The Silicon Drift Detector for the IXO High Time Resolution Spectrometer Peter Lechner ∗a , Carine Amoros b , Didier Barret b , Pierre Bodin c , Martin Boutelier b , Rouven Eckhardt a , Carlo Fiorini d , Eckhard Kendziorra e , Karine Lacombe b , Adrian Niculae a , Benjamin Pouilloux c , Roger Pons b , Damien Rambaud b , Laurent Ravera b , Christian Schmid f , Heike Soltau a , Lothar Strüder gh , Christoph Tenzer e , Jörn Wilms f a PNSensor GmbH, Römerstr. 28, 80803 München, Germany; b Centre d’Etude Spatiale des Rayonnements, 9 Av. du Colonel Roche, 31028 Toulouse, France; c Centre National d'Etudes Spatiales, 18 Av. Edouard Belin, 31401 Toulouse, France; d Politecnico di Milano, Dipartimento di Elettronica e Informazione, Via Golgi 40, 20133 Milan, Italy; e Institut für Astronomie und Astrophysik, Sand 1, 72076 Tübingen, Germany; f Dr. Remeis-Observatorium, Sternwartstr. 7, 96049 Bamberg, Germany; g Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr., 85741 Garching, Germany; h MPI Halbleiterlabor, Otto-Hahn-Ring 6, 81739 München, Germany; ABSTRACT The High Time Resolution Spectrometer (HTRS) is one of six scientific payload instruments of the International X-ray Observatory (IXO). HTRS is dedicated to the physics of matter at extreme density and gravity and will observe the X-rays generated in the inner accretion flows around the most compact massive objects, i.e. black holes and neutron stars. The study of their timing signature and in addition the simultaneous spectroscopy of the gravitationally shifted and broadened iron line allows for probing general relativity in the strong field regime and understanding the inner structure of neutron stars. As the sources to be observed by HTRS are the brightest in the X-ray sky and the studies require good photon statistics the instrument design is driven by the capability to operate at extremely high count rates. The HTRS instrument is based on a monolithic array of Silicon Drift Detectors (SDDs) with 31 cells in a circular envelope and a sensitive volume of 4.5 cm 2 x 450 µm. The SDD principle uses fast signal charge collection on an integrated amplifier by a focusing internal electrical field. It combines a large sensitive area and a small capacitance, thus facilitating good energy resolution and high count rate capability. The HTRS is specified to provide energy spectra with a resolution of 150 eV (FWHM at 6 keV) at high time resolution of 10 ȝsec and with high count rate capability up to a goal of 2·10 6 counts per second, corresponding to a 12 Crab equivalent source. As the HTRS is a non-imaging instrument and will target only point sources it is placed on axis but out of focus so that the spot is spread over the array of 31 SDD cells. The SDD array is logically organized in four independent 'quadrants', a dedicated 8-channel quadrant readout chip is in development. Keywords: International X-ray Observatory, IXO, High Time Resolution Spectrometer, HTRS, X-ray Astronomy, X-ray Spectroscopy, X-ray Timing, Silicon Drift Detector, SDD 1. INTRODUCTION The International X-ray Observatory (IXO) [1] is a joint high-energy mission of the US-American, European, and Japanese space agencies with a projected launch in 2021 to a large-amplitude halo orbit around the second Lagrange point (L2) of the sun-earth system. IXO will address some of the most fundamental questions in contemporary astrophysics and cosmology. Among the primary science goals are the investigation of black holes and matter under extreme conditions, the study of formation and evolution of galaxies, clusters and large scale structure, and to trace the life cycles of matter and energy. This variety of scientific tasks requires high sensitivity and high spatial resolution over a ∗ corresponding author, peter.lechner@pnsensor.de; phone +49.89.83940051; www.pnsensor.de; www.hll.mpg.de; High Energy, Optical, and Infrared Detectors for Astronomy IV, edited by Andrew D. Holland, David A. Dorn Proc. of SPIE Vol. 7742, 77420W · © 2010 SPIE · CCC code: 0277-786X/10/$18 · doi: 10.1117/12.857260 Proc. of SPIE Vol. 7742 77420W-1 Downloaded from SPIE Digital Library on 16 Aug 2010 to 128.183.56.12. Terms of Use: http://spiedl.org/terms