Title: First functionality tests of a 64 x 64 pixel DSSC sensor module connected to the complete ladder readout,
Abstract: The European X-ray Free Electron Laser (XFEL.EU) will provide every 0.1 s a
train of 2700 spatially coherent ultrashort X-ray pulses at 4.5 MHz repetition
rate. The Small Quantum Systems (SQS) instrument and the Spectroscopy and
Coherent Scattering instrument (SCS) operate with soft X-rays between 0.5 keV -
6keV. The DEPFET Sensor with Signal Compression (DSSC) detector is being
developed to meet the requirements set by these two XFEL.EU instruments. The
DSSC imager is a 1 mega-pixel camera able to store up to 800 single-pulse
images per train. The so-called ladder is the basic unit of the DSSC detector.
It is the single unit out of sixteen identical-units composing the
DSSC-megapixel camera, containing all representative electronic components of
the full-size system and allows testing the full electronic chain. Each DSSC
ladder has a focal plane sensor with 128 x 512 pixels. The read-out ASIC
provides full-parallel readout of the sensor pixels. Every read-out channel
contains an amplifier and an analog filter, an up-to 9 bit ADC and the digital
memory. The ASIC amplifier have a double front-end to allow one to use either
DEPFET sensors or Mini-SDD sensors. In the first case, the signal compression
is a characteristic intrinsic of the sensor; in the second case, the
compression is implemented at the first amplification stage. The goal of signal
compression is to meet the requirement of single-photon detection capability
and wide dynamic range. We present the first results of measurements obtained
using a 64 x 64 pixel DEPFET sensor attached to the full final electronic and
data-acquisition chain.