The Demonstration Model of the ATHENA X-IFU Cryogenic AntiCoincidence Detector

The Cryogenic AntiCoincidence Detector (CryoAC) of ATHENA X-IFU is designed to reduce the particle background of the instrument and to enable the mission science goals. It is a 4 pixel silicon microcalorimeter sensed by an Ir/Au TES network. We have developed the CryoAC Demonstration Model, a prototype aimed to probe the critical technologies of the detector, i.e. the suspended absorber with an active area of 1 cm2 ; the low energy threshold of 20 keV; and the operation connected to a 50 mK thermal bath with a power dissipation less than 40 nW. Here we report the test performed on the first CryoAC DM sample (namely the AC-S10 prototype), showing that it is fully compliant with its requirements.