Mitigation of Finite Bandwidth Effects in Time-Division-Multiplexed SQUID Readout of TES Arrays
Malcolm Durkin, J. S. Adams, S. R. Bandler, J. A. Chervenak, E. V. Denison, W. B. Doriese, Shannon M. Duff, F. M. Finkbeiner, Joseph W. Fowler, Johnathon D. Gard, G. C. Hilton, Ruslan Hummatov, K. D. Irwin, Young Il Joe, Richard L. Kelley, Caroline A. Kilbourne, Antoine R. Miniussi, Kelsey M. Morgan, G. C. O’Neil, Christine G. Pappas, F. S. Porter, C. D. Reintsema, D. A. Rudman, Kazuhiro Sakai, S. J. Smith, Robert W. Stevens, Daniel S. Swetz, Paul Szypryt, Joel N. Ullom, Leila R. Vale, Nicholas A. Wakeham
Abstract
Time division multiplexing (TDM) is being developed as the readout technology of the X-ray integral field unit (X-IFU), a 3,168-pixel X-ray transition-edge sensor (TES) imaging spectrometer that is part of the European Space Agency's Athena satellite mission. Recent improvements in the low X-ray event count rate performance of TDM have been driven by increases in multiplexer bandwidth and the mitigation of settling transients. These methods and design changes have improved the 32-row multiplexed resolution of a NASA LPA 2.5a array from an initial (2.73 ± 0.03) eV to (1.97 ± 0.01) eV resolution at 5.9 keV. We discuss these recent advances in TDM readout, which have been implemented in an 8-column × 32-row spectrometer that will be deployed at the Lawrence Livermore National Laboratory electron beam ion trap (EBIT) facility, and present a model that will inform the design of future systems.