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Development of the DEPFET Sensor with Signal Compression: a Large Format X-ray Imager with Mega-Frame Readout Capability for the European XFEL

Abstract: The main concepts and the major achievements in the development of the DEPFET Sensor with Signal Compression (DSSC) are presented. This is an ultra-high speed detector system for the European XFEL. The DSSC will be able to record X-ray images with a maximum frame rate of 4.5MHz. The system is based on a silicon pixel sensor with a DEPFET as a central amplifier structure and has detection efficiency close to 100% for X-rays from 0.5 keV up to 10keV. The sensor will have a size of 210x210 mm2 composed of 1024x1024 pixels. 256 readout ASICs are bump-bonded to the detector in order to provide full parallel readout. The signals coming from the sensor are processed by an analog filter, digitized by 8-bit ADCs and locally stored in a SRAM. In order to fit the dynamic range of 104 photons of 1keV per pixel into a reasonable output signal range, achieving simultaneously single 1keV photon resolution, a non-linear characteristic is required. The proposed DEPFET provides dynamic range compression at the sensor level. The most challenging property is that the single 1keV photon resolution and the high dynamic range are accomplished within the 220ns frame rate. The proof of principle of the non-linear DEPFET response has been obtained with measurements on newly fabricated pixel structures. Advanced prototypes of all main building blocks have been produced and their properties experimentally investigated. The complete readout chain, comprising a non-linear DEPFET and an 8x8 ASIC prototype fully representative of the final integrated readout electronics, has been measured. All the main operating features of the system have been investigated including the power cycling mode needed for the focal plane cooling strategy. The latest simulations of the final sensor layout and the experimental data obtained with the existing prototypes have been used to simulate the expected final DSSC response. The system simulation has shown the
Speaker: Matteo Porro - Max Planck Institute - Munich
Speaker Bio: Matteo Porro earned his Masterís degree in Electronics Engineering and his Ph.D. in Radiation Science and Technology at Politecnico di Milano, Italy. His research interests focus on the development of low-noise silicon detectors and of the associated readout ASICs. During his Ph.D. he has developed the electrical and noise model of the DEPFET device for X-ray astronomy and has designed the readout ASIC for a compact gamma camera for medical applications. Since 2005 Matteo Porro has been a research scientist at the Semiconductor Laboratory of Max Planck Institute in Munich, Germany. He has been responsible of the development of the ASTEROID ASIC: a multi-channel low-noise integrated circuit for DEPFET matrices. The ASIC is scheduled to be used in the BepiColombo mission of ESA, which will investigate X-ray fluorescence from Mercury. His ASIC development activity also includes the design of the readout for pnCCDs for optical astronomy and for experiments with the new generation of X-ray Free Electron Lasers. In 2007 he became the coordinator and the P.I. of the DSSC project. The project aims at the development of a DEPFET-based large format X-ray imager with mega-frame readout capability for the European XFEL in Hamburg. In 2010 he received the Radiation Instrumentation Early Career Award from the IEEE Nuclear and Plasma Sciences Society. He is author and coauthor of more than 70 publications and one patent.
Poster Link: Poster
Presentation: Presentation on 10/26/2012 (PDF)