Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 28: Superconductivity - Applications I : Cryodetectors
TT 28.6: Vortrag
Dienstag, 8. März 2005, 15:30–15:45, TU H104
Low Temperature Calorimeters for Precise Lamb shift Measurements on Hydrogen-Like Heavy Ions — •Alexander Bleile1, V. Andrianov1, P. Egelhof1, S. Kraft1, D. McCammon2, H.J. Meier1, J.P. Meier1 und C. Stahle3 — 1GSI, Darmstadt / Univ. Mainz — 2Univ. of Wisconsin, Madison, USA — 3Goddard Space Flight Center, Greenbelt, USA
The precise determination of the Lamb shift in hydrogen-like heavy ions provides a sensitive test of quantum electrodynamics in very strong Coulomb fields, not accessible otherwise. To increase the accuracy of the Lamb shift measurement on stored 238U91+ ions at the ESR storage ring at GSI, a calorimetric low temperature detector for hard X-rays was developed. The experimental requirements for the detector are the high absorption efficiency and the relative energy resolution of the order of 10−3 for 50-100 keV X-rays. The detector consists of arrays of silicon thermistors and X-ray absorbers made of high Z material. A test array consisting of 8 pixels was recently set up and tested, the achieved energy resolution ΔE=75-140 eV @ 60 keV is close to fulfill the demands of the experiment. The status of the experiment will be presented and results of first test measurements at the ESR will be discussed.