Invited Speakers

Ulrich TRUNK (DESY-Hamburg)

AGIPD: A multi Megapixel, multi Megahertz X-Ray Camera for the European XFEL

Title: AGIPD: A multi Megapixel, multi Megahertz X-Ray Camera for the European XFEL
Author: Ulrich Trunk, on behalf of the AGIPD consortium
Affiliation: Deutsches Elektronen-Synchrotron, DESY-Hamburg, Germany
Email: Ulrich.Trunk[at]desy.de
URL: http://photon-science.desy.de/research/technical_groups/detectors/
Abstract: AGIPD is a hybrid pixel detector developed by DESY, PSI, and the Universities of Bonn and Hamburg. It is targeted for use at the European XFEL, a source with unique properties: a train of up to 2700 pulses is repeated at 10Hz rate. The pulses inside a train are ≤100fs long and separated by 220ns, containing 1012 photons of 12keV each.
The readout ASICs with 64x64 pixels each have to cope with these properties: Single photon sensitivity and a dynamic range up to >104 photons/pixel in the same image as well as storage for as many as possible images of a pulse train for delayed readout, prior to the next train. The high impinging photon flux also requires a very radiation hard design of sensor and ASIC, which uses 130nm CMOS technology and radiation tolerant techniques.
The signal path inside a pixel of the ASIC consists of a charge sensitive preamplifier with 3 individual gains, adaptively selected by a subsequent discriminator. The preamp also feeds to a correlated double sampling stage, which writes to an analogue memory to record 352 frames. It is random-access, so it can be used most efficiently by overwriting bad or empty images. Encoded gain information is stored to a similar memory. Readout of these memories is by a common charge sensitive amplifier in each pixel, and multiplexers on four differential ports. Operation of the ASIC is controlled via a command interface, using 3 LVDS lines. It also serves to configure the chip's operational parameters and timings.
We will present the AGIPD detector with special focus on the design of the readout ASIC and will show various experimental results obtained with either a single chip, a single module, or a multi-module system.
Biographical Sketch: Dr. Ulrich Trunk graduated in high energy astro-particle physics and received his PHD from University of Heidelberg in 2001 for the development and radiation hardness characterization of a readout ASIC for silicon microstrip detectors. From 2001 to 2007 he held positions at Max-Planck-Institute for Nuclear Physics and University of Heidelberg, heading ‘ASIC-Labor Heidelberg’, a common installation of the two institutions, and developing various ICs for detector readout. These included chips employed in the LHCb experiment at CERN, a spectroscopic amplifier working at cryogenic temperatures and a self-triggered microstrip readout chip, which is currently adapted to the CBM experiment at FAIR/GSI (Darmstadt, Germany). Since 2007 he is developing hybrid pixel detectors for photon science at DESY (Hamburg, Germany). Here the primary focus of his work is on high speed and low noise readout ASICs in deep submicron technologies. An additional concern of his work is radiation hardness of these detectors in terms of design and characterization, since these will be used at the European XFEL source.