Demonstration Of Athena X-Ifu Compatible 40-Row Time-Division-Multiplexed Readout

Time-division multiplexing (TDM) is the backup readout technology for the X-ray Integral Field Unit (X-IFU), a 3168-pixel X-ray transition-edge sensor (TES) array that will provide imaging spectroscopy for european space agency's Athena satellite mission. X-IFU design studies are considering readout with a multiplexing factor of up to 40. We present data showing 40-row TDM readout (32 TES rows + 8 repeats of the last row) of TESs that are of the same type as those being planned for X-IFU, using measurement and analysis parameters within the ranges specified for X-IFU. Single-column TDM measurements have best-fit energy resolution of (1.91 +/- 0.01) eV for the Al K alpha complex (1.5 keV), (2.10 +/- 0.02) eV for Ti K alpha (4.5 keV), (2.23 +/- 0.02) eV for Mn K alpha (5.9 keV), (2.40 +/- 0.02) eV for Co Ka (6.9 keV), and (3.44 +/- 0.04) eV for Br K alpha (11.9 keV). Three-column measurements have best-fit resolution of (2.03 +/- 0.01) eV for Ti K alpha and (2.40 +/- 0.01) eV for Co K alpha. The degradation due to the multiplexed readout ranges from 0.1 eV at the lower end of the energy range to 0.5 eV at the higher end. The demonstrated performance meets X-IFU's energy-resolution and energy-range requirements. True 40-row TDM readout, without repeated rows, of kilopixel scale arrays of X-IFU-like TESs is now under development.