Previous | Session 12 | Next | Author Index | Block Schedule
K. D. Irwin, J. A. Beall, W. B. Doriese, W. D. Duncan, L. Ferreira, G. C. Hilton, C. D. Reintsema, D. R. Schmidt, J. N. Ullom, L. R. Vale, Y. Xu, B. L. Zink (NIST)
NIST is working with NASA/Goddard Space Flight Center (GSFC) to develop multiplexed x-ray microcalorimeter arrays optimized for the Constellation-X mission. These arrays are based on superconducting transition-edge sensors (TES) read out with multiplexed superconducting quantum interference device (SQUID) amplifiers. We present recent progress in improving the x-ray energy resolution through engineering the device geometry, and present recent results with 8- and 16-channel multiplexers.
In order to achieve the ambitious x-ray energy resolution goals for the Constellation-X microcalorimeters, we have conducted extensive investigations of the high-frequency unexplained noise in TES sensors as a function of operating resistance, current density, applied magnetic field, and device geometry. Using the measured dependencies of the unexplained noise, we have optimized the design of our TES x-ray sensors and achieved FWHM energy resolutions of 2.4 eV at the 5.9 keV Mn K\alpha complex, which is a significant step towards the Constellation-X resolution goal of 2 eV at 5.9 keV.
We also present progress in the development of time-division SQUID multiplexers for the readout of large x-ray calorimeter arrays. We present results from x-ray microcalorimeters in 8- and 16-channel multiplexers. We describe the constraints on the system architecture, and present a practical design for a 32-channel MUX to be used in a kilopixel array.
Finally, we have extended this work to develop TES microcalorimeters for higher energy applications, such as the study of Ti emission lines from supernova remnants, including high-resolution velocity diagnostics. We have obtained a spectral resolving power of 4300 (energy / half-energy width) at the 103 keV Gd \gamma-ray line using a TES with a Sn absorber.
We are grateful for technical support from the NASA/GSFC microcalorimeter group, and for financial support from NASA through the Constellation-X program and Grant NDPR S06561-G.
Previous | Session 12 | Next
Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.