1. A Multichannel Superconducting Tunnel Junction Detector for High-Resolution X-Ray Spectroscopy of Magnesium Diboride Films.
- Author
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Friedrich, Stephan, Vailionis, Arturas, Drury, Owen, Niedermayr, Thomas, Funk, Tobias, Kang, W.N., Eun-Mi Choi, Hyeong-Jin Kim, Sung-Ik Lee, Cramer, Stephen P., Changyoung Kim, and Labov, Simon E.
- Subjects
DETECTORS ,JOSEPHSON junctions ,SUPERCONDUCTORS ,MAGNESIUM diboride ,THIN films - Abstract
We have built a high-resolution soft x-ray spectrometer using a 3 × 3 array of superconducting Nb-AI-AIOx-AI-Nb tunnel junctions. The detector is cooled to ∼0.1 K by a two-stage adiabatic demagnetization refrigerator while being held at the end of a 40-cm-long detector snout that can be inserted into an experimental chamber. The 0.6 mm × 0.6 mm array has an energy resolution of 10-15 eV FWHM for x-ray energies below I kev and total count rate capabilities above 100 000 counts/s. We demonstrate the capabilities of the instrument in a study of anisotropy in c-axis oriented MgB[sub 2] films by near edge x-ray absorption spectroscopy. The absorption fine structure at the B K-edge differs for excitation with x-rays polarized along the c-axis and in the ab-plane of the MgB[sub 2] film. We discuss the implications of the anisotropy for the density of states in MgB[sub 2] at the Fermi surface. [ABSTRACT FROM AUTHOR]
- Published
- 2003
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