Berlin 2001 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
A: Atomphysik
A 17: Posters Friday (Spectroscopy)
A 17.55: Poster
Freitag, 6. April 2001, 12:30–15:00, AT3
Calorimetric Low-Temperature Detectors for High Resolution X-Ray Spectroscopy on Stored Highly Stripped Heavy Ions — •A. Bleile1,2, P. Egelhof1,2, D. Mc Cammon3, S. Kraft1,2, H.J. Meier1,2, A. Shrivastava1,2, C.K. Stahle3, and M. Weber1,2 — 1Univ. Mainz, Germany — 2GSI Darmstadt, Germany — 3Univ. Madison, USA
The precise determination of the Lamb shift in heavy hydrogen-like ions provides a sensitive test of quantum electrodynamics in very strong Coulomb fields, not accessible otherwise. For the investigation of the 1s Lamb shift in 208Pb81+ or 238U91+ at the heavy ion storage ring ESR of GSI Darmstadt, a high resolving x-ray detector for hard x-rays (E≤100 keV) is needed to measure the Lyman-α transitons with sufficient accuracy. For this purpose a calorimetric low-temperature x-ray detector is presently developed. Such a detector measures the temperature rise of an absorber due to the energy deposited by the incident x-ray. The potential advantage of this detection concept over conventional semiconductor detectors is due to more complete detection of the deposited energy and a better counting statistics of the detected quanta (phonons). The detector modules consist of silicon thermistors, which are used as thermometers and x-ray absorbers glued on the top of the thermistors. The final detector concept foresees three calorimeter arrays, consisting of 36 pixels each. The active area of 1 pixel is about 1 mm2. The detector performance presently achieved perfectly fulfills the demands of the Lamb shift experiment. The best results were observed with Pb as absorber material. For 60 keV x-rays an energy resolution of ΔE(FWHM)=48 eV is obtained.