First results of the ATHENA/X-IFU digital readout electronics prototype

The Digital Readout Electronics (DRE) of the X-ray Integral Field Unit (X-IFU) instrument onboard Athena is made of two main parts: the DRE demultiplexor (DRE-DEMUX) and the DRE event processor (DRE-EP). The DRE-DEMUX drives the frequency domain multiplexed readout of the X-IFU Focal Plane Assembly (FPA) and it linearises the readout chains to increase their dynamic range. The DRE-EP processes the pixels’s data in order to detect the events and to measure the X-ray photon energy and arrival time. We have developed a prototype of the DRE-DEMUX module. We used a modular architecture with several boards in order to validate the different key functionalities one by one with a short design-test-rework cycle. To test the functionalities and performances of the DRE-DEMUX breadboards in a representative environment we developed several test equipments. Although the prototype is not flight representative in many aspects (EMC, power supplies, components grade, . . . ) it is intended to demonstrate the DRE-DEMUX functionalities and to validate the numerous operating procedures of our electronics. The preliminary tests conducted on the DRE-DEMUX prototype coupled to the dedicated test equipments validated its functionalities but also demonstrated that it is compliant with the its energy resolution requirement, which is the most constraining for the DRE.