Showing papers by "Robert Schoelkopf published in 1988"
TL;DR: In this paper, a microcalorimeter was proposed to measure the energy released in the absorption of a single photon by sensing the rise in temperature of a small absorbing structure, which can in principle be made as low as 1 eV.
Abstract: Thermal detectors for X-ray spectroscopy combining high spectral resolution and quantum efficiency have been developed. These microcalorimeters measure the energy released in the absorption of a single photon by sensing the rise in temperature of a small absorbing structure. The ultimate energy resolution of such a device is limited by the thermodynamic power fluctuations in the thermal link between the calorimeter and isothermal bath and can in principle be made as low as 1 eV. The performance of a real device is degraded due to noise contributions such as excess 1/f noise in the thermistor and incomplete conversion of energy into phonons. The authors report some recent advances in thermometry, X-ray absorption and thermalization, fabrication techniques, and detector optimization in the presence of noise. These improvements have resulted in a device with a spectral resolution of 17 eV FWHM, measured at 6 keV. >
59 citations
21 Dec 1988
TL;DR: The use of microcalorimeters for high-resolution, high quantum efficiency, non-dispersive X-ray spectroscopy has been demonstrated over the past few years as discussed by the authors.
Abstract: The use of microcalorimeters for high-resolution, high quantum efficiency, non-dispersive X-ray spectroscopy has been demonstrated over the past few years. During this time the energy resolution in the 1-10 keV band has improved from a value of-140 eV (FWHM), comparable to the best solid-state (Si/Li) detectors, to a value of-17 eV. We are presently working on improving the energy resolution by designing devices that have been optimized with respect to heat capacity, thermal conductance, X-ray absorbing material, thermistor geometry and thermistor implant concentration. In addition we have been working on the design of an integrated spectrometer consisting of a He4 cryostat containing an adiabatic demagnetization refrigerator, non-X-ray blocking filters and control and signal processing electronics. The essential components for such a system have been assembled at the University of Wisconsin and a similar system is being developed at Goddard. These systems will demonstrate the feasibility of this approach for space flight use, in particular for the NASA AXAF mission, and serve as research tools for further work in X-ray calorimetry. In this paper we give an overview of X-ray calorimetry, present the results of on-going X-ray tests, and discuss an approach for building an X-ray calorimeter spectrometer.
5 citations