Speaker
Dr
David Pennicard
(DESY)
Description
Single-photon-counting pixel detectors provide high signal-to-noise ratios, fast readout, and sophisticated functionality, making them the technology of choice of many experiments at synchrotrons. LAMBDA (Large Area Medipix3-Based Detector Array) has been developed to improve on existing photon-counting systems. LAMBDA uses the Medipix3 readout chip, and combines the small pixel size (55 µm) and flexibility of this chip with a large tileable module design of 1536 x 512 pixels (12 chips). The high-speed readout system currently runs at 1000 frames per second with no dead time between frames. Additionally, the system can be used in an energy-binning mode to provide additional information in experiments with polychromatic sources. A series of LAMBDA systems have been produced, commissioned and used in experiments at synchrotrons – for example, time-resolved experiments studying soft matter under shear forces.
To allow high-speed experiments with hard X-rays, the LAMBDA system has been combined with different high-Z sensor materials, in collaboration with other institutes and industry. Room-temperature systems using GaAs and CdTe systems have been assembled and tested at beamlines. These show acceptable image quality after flat-field correction. These first systems provide an area of 768 x 512 pixels, and larger systems using multiple tiled sensors are in development. The first Germanium hybrid pixel detectors have been also been produced. These have a layout of 256 x 256 pixels of 55µm, and work successfully. Due to the high quality of the sensor material, the germanium sensor provides a higher raw image uniformity. Larger germanium sensors are now in production.
To reduce the dead area in large LAMBDA systems, development has also started on a version of LAMBDA where the wire bonds are replaced with through-silicon vias, and the guard ring region is reduced by using an edgeless silicon sensor. The TSV processing will be done by Fraunhofer IZM. A radiation hard edgeless sensor layout is being designed using TCAD simulation.
Author
Dr
David Pennicard
(DESY)
Co-authors
Dr
Bernd Struth
(DESY)
Prof.
Heinz Graafsma
(DESY)
Mr
Helmut Hirsemann
(DESY)
Dr
Jiaguo Zhang
(Institute of Experimental Physics, University of Hamburg)
Mr
Milija Sarajlic
(DESY)
Mr
Sergej Smoljanin
(DESY)
