  We present a test platform for the Athena X-IFU detection chain, which will
serve as the first demonstration of the representative end-to-end detection and
readout chain for the X-IFU, using prototypes of the future flight electronics
and currently available subsystems. This test bench, housed in a commercial
two-stage ADR cryostat, includes a focal plane array placed at the 50 mK cold
stage of the ADR with a kilopixel array of transition-edge sensor
microcalorimeter spectrometers and associated cold readout electronics.
Prototype room temperature electronics for the X-IFU provide the readout, and
will evolve over time to become more representative of the X-IFU mission
baseline. The test bench yields critical feedback on subsystem designs and
interfaces, in particular the warm readout electronics, and will provide an
in-house detection system for continued testing and development of the warm
readout electronics and for the validation of X-ray calibration sources. In
this paper, we describe the test bench subsystems and design, characterization
of the cryostat, and current status of the project.
