Energy resolution and high count rate performance of superconducting tunnel junction x-ray spectrometers
- Lawrence Livermore National Laboratory, P.O. Box 808, L-401, Livermore, California 94551 (United States)
- Conductus, Inc., 969 West Maude Ave., Sunnyvale, California 94086 (United States)
We present experimental results obtained with a cryogenically cooled, high-resolution x-ray spectrometer based on a 141{mu}m{times}141{mu}m Nb-Al-Al{sub 2}O{sub 3}-Al-Nb superconducting tunnel junction (STJ) detector in a demonstration experiment. Using monochromatized synchrotron radiation we studied the energy resolution of this energy-dispersive spectrometer for soft x rays with energies between 70 and 700 eV and investigated its performance at count rates up to nearly 60000 cps. At count rates of several 100 cps we achieved an energy resolution of 5.9 eV (FWHM) and an electronic noise of 4.5 eV for 277 eV x rays (the energy corresponding to C K). Increasing the count rate, the resolution 277 eV remained below 10 eV for count rates up to {approximately}10000cps and then degraded to 13 eV at 23000 cps and 20 eV at 50000 cps. These results were achieved using a commercially available spectroscopy amplifier with a baseline restorer. No pile-up rejection was applied in these measurements. Our results show that STJ detectors can operate at count rates approaching those of semiconductor detectors while still providing a significantly better energy resolution for soft x rays. Thus STJ detectors may prove very useful in microanalysis, synchrotron x-ray fluorescence (XRF) applications, and XRF analysis of light elements (K lines) and transition elements (L lines). {copyright} {ital 1998 American Institute of Physics.}
- OSTI ID:
- 566182
- Journal Information:
- Review of Scientific Instruments, Vol. 69, Issue 1; Other Information: PBD: Jan 1998
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
INCLUDING NUCLEAR AND PARTICLE DETECTORS
X-RAY SPECTROMETERS
SYNCHROTRON RADIATION
ENERGY RESOLUTION
PERFORMANCE
FLUORESCENCE
EV RANGE 100-1000
NIOBIUM
ALUMINIUM
TUNNEL EFFECT
X-RAY FLUORESCENCE ANALYSIS
ALUMINIUM OXIDES
EV RANGE 10-100
FABRICATION
USES
SUPERCONDUCTING JUNCTIONS
X-RAY DETECTION