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Optimized Transition-Edge X-ray Microcalorimeter with 2.4 eV Energy Resolution at 5.9 keV



Joel Ullom, James A. Beall, W.Bertrand (Randy) Doriese, William Duncan, S. L. Ferreira, Gene C. Hilton, Kent D. Irwin, Carl D. Reintsema, Leila R. Vale


We present measurements from a series of transition- edge x-ray microcalorimeters designed for optimal energy resolution. We used the geometry of the sensors to control their heat capacity and employed additional normal metal features and a perpendicular magnetic field to control the sharpness of the superconducting-to-normal transition. These degrees of control allow an optimal selection of sensor saturation energy and noise. Successive design changes improved the measured energy resolution of the sensors from 4.5 eV full-width-at-half-maximum at 5.9 keV to 2.4 eV at 5.9 keV. The sensors have an estimated quantum efficiency of 55% at 5.9 keV and measured thermal recovery times ranging from 80 to 260 microseconds. Energy-dispersive sensors with this combination of energy resolution, quantum efficiency, and speed are well matched to applications in x-ray astrophysics and terrestrial materials analysis.
Applied Physics Letters


microcalorimeter, TES, unexplained noise


Ullom, J. , Beall, J. , Doriese, W. , Duncan, W. , Ferreira, S. , Hilton, G. , Irwin, K. , Reintsema, C. and Vale, L. (2005), Optimized Transition-Edge X-ray Microcalorimeter with 2.4 eV Energy Resolution at 5.9 keV, Applied Physics Letters, [online], (Accessed April 15, 2024)
Created October 31, 2005, Updated October 12, 2021