AVS 50th International Symposium
    Thin Films Wednesday Sessions
       Session TF+MM-WeA

Invited Paper TF+MM-WeA4
Bilayer Transition-edge Sensors for X-ray Calorimeter and Infrared Bolometer Arrays

Wednesday, November 5, 2003, 3:00 pm, Room 326

Session: Sensors, Smart Films and Functional Materials
Presenter: J.N. Ullom, National Institute of Standards and Technology
Authors: J.N. Ullom, National Institute of Standards and Technology
J.A. Beall, National Institute of Standards and Technology
J. Beyer, PTB, Guest Researcher NIST
S. Deiker, National Institute of Standards and Technology
W.B. Doriese, National Institute of Standards and Technology
G.C. Hilton, National Institute of Standards and Technology
K.D. Irwin, National Institute of Standards and Technology
C.D. Reintsema, National Institute of Standards and Technology
L.R. Vale, National Institute of Standards and Technology
Correspondent: Click to Email
Microcalorimeters and bolometers made from thin superconducting films cooled to temperatures near 100 mK have made dramatic progress in recent years. These devices provide an order of magnitude improvement in energy resolution over existing semiconductor x-ray sensors and are likely to be used in upcoming astronomical instruments spanning the spectrum from x-ray to millimeter wavelengths. The sensitivity of these devices is derived from the low heat capacities and thermal conductivities possible near 100 mK and from the strong dependence of resistance on temperature in the superconducting-to-normal transition. Our devices are made from bilayers of a normal metal and a superconductor. Use of a bilayer allows the transition temperature and resistivity of the sensors to be precisely controlled. In this talk, we describe recent progress towards kilopixel sensor arrays using multiplexed SQUID readout. We are building arrays of x-ray microcalorimeters for two applications: energy-dispersive x-ray spectroscopy on scanning electron microscopes and for the upcoming NASA satellite Constellation-X. We are building arrays of submillimeter bolometers for the SCUBA-2 camera on the James-Clerk Maxwell Telescope on Mauna Kea. At this time, the measured noise in both microcalorimeters and bolometers approaches but does not equal the value predicted from simple thermodynamics. We will present measurements of this excess noise and describe recent mitigation efforts.