By Arne Rau (Athena/WFI Project Scientist)

Between October 14th and 17th, the WFI Consortium met again for its semi-annual gathering. The 10th consortium meeting was held at the University and the Astronomical Observatory in Strasbourg, France. It was attended by ~75 members from nearly all of the 23 Consortium Partner Institutes, as well as representatives from ESA, the German Space Agency DLR, and the X-IFU Consortium.

Following the successful Instrument Preliminary Requirements Review in November 2018 the WFI is currently in Phase B1 (Preliminary Definition) and the instrument development continues full steam ahead towards the next milestone, the System Requirements Review in spring 2021, ahead of mission adoption expected in late 2021. The Consortium Meeting was an opportunity to share and discuss the status and the latest news on the instrument, its science and all of its subsystems.

Impressive progress has been made in all of the critical development aspects of the WFI. The first batch of the pre-flight DEPFET sensor production has been completed at the Semiconductor Laboratory of the Max Planck Society and the devices are now under test at MPE. First results indicate the expected excellent performance.

The large collecting area of the Athena optics coupled with the impressive readout times of the detectors (5ms for the Large Detector Array and 80µs for the Fast Detector) generate high data rates that need to be processed in the Detector Electronics in real time. In order to demonstrate this capability, a breadboard test setup of the Frame Processor has been developed. Using digital data from a programmable emulator, the real-time performance was successfully verified, showing that the electronics can handle sources as bright as in the case of the Fast Detector 2.5 times the Crab (~195000 photons/s) without losses. The next steps will include testing with data from a real detector.

The filter and filter wheel developments have also passed a critical milestone with successful acoustic noise tests performed at the AGH Krakow over the summer. These tests, performed with a Filter Wheel Demonstrator and flight-representative filters, validated the survival at qualification level acoustic loads and verified that a vacuum enclosure will not be needed for the instrument. This is an important step in the optimization of the instrument within its allocated resource budgets.

The plenary session also included presentations by A. Stefanescu (ESA), the X-IFU instrument scientist F. Pajot as well as two talks summarizing the Athena optics development (by M. Bavdaz, ESA) and the Silicon Pore Optics Technology (by M. Collon, COSINE).

The next consortium meeting will be held at MPE in April 2020.