Sabrina Geyer

Observation of the 2p3/2→2s1/2 intra-shell transition in He-like uranium

We present the first observation of the 1s2p 3P2→1s2s 3S1 transition in He-like uranium. The experiment was performed at the internal gas-jet target of the ESR storage ring at GSI exploiting a Bragg crystal spectrometer and a germanium solid-state detector. Using the 1s22p 2P3/2→1s22s 2S1/2 transition in Li-like uranium as reference and the deceleration capabilities of the ESR storage ring, we obtained the first evaluation of the energy of an intra-shell transition for a He-like heavy ion.

Differential energy measurement between He- and Li-like uranium intra-shell transitions

We present the first clear identification and highly accurate measurement of the intra-shell transition

Polarization studies of radiative electron capture into highly-charged uranium ions

1s2p\, ^3P_2 \to 1s2s\, ^3S_1

Polarized tunable monoenergetic x-rays produced by radiative electron capture into the K-shell of Xe54+

of He-like uranium performed via X-ray spectroscopy. The present experiment has been conducted at the gas-jet target of the ESR storage ring in GSI (Darmstadt, Germany) where a Bragg spectrometer, with a bent germanium crystal, and a Ge(i) detector were mounted. Using the ESR deceleration capabilities, we performed a differential measurement between the

Polarization Measurements of Radiative Electron Capture Transitions in Highly Charged Ions

1s2p\, ^3P_2 \to 1s2s\, ^3S_1

Polarization and anisotropic emission of K-shell radiation from heavy few electron ions

He-like U transition energy, at 4510 eV, and the

Sprachliches Handeln von U3‐Fachkräften – Neuverortung aus linguistischer Perspektive

1s^22p\ ^2P_{3/2} \to 1s^22s\, ^2S_{1/2}

Sprachförderung im U3‐Bereich

Li-like U transition energy, at 4460 eV. By a proper choice of the ion velocities, the X-ray energies from the He- and Li-like ions could be measured, in the laboratory frame, at the same photon energy. This allowed for a drastic reduction of the experimental systematic uncertainties, principally due to the Doppler effect, and for a comparison with the theory without the uncertainties arising from one-photon QED predictions and nuclear size corrections.

Sprachliches Handeln in der Sprachförderung

Recent advances in the development of 2D microstrip detectors open up new possibilities for hard x-ray spectroscopy, in particular for polarization studies. These detectors make ideal Compton polarimeters, which enable us to study precisely the polarization of hard x-rays. Here, we present recent results from measurements of Radiative Electron Capture into the K-shell of highly-charged uranium ions. The experiments were performed with a novel 2D Si(Li) Compton polarimeter at the Experimental Storage Ring at GSI. Stored and cooled beams of U91+ and U92+ ions, with kinetic energies of 43 MeV/u and 96 MeV/u respectively, were crossed with a hydrogen gasjet. The preliminary data analysis shows x-rays from the K-REC process, emitted perpendicularly to the ion beam, to be strongly linearly polarized.

Zusammenfassung, Fazit und Ausblick

Many physical processes such as bremsstrahlung, synchrotron radiaton and radiative recombination produce polarized X-rays. However, only a few facilities are able to deliver tunable monoenergetic high quality beams of almost completely polarized X-rays to the user. We used radiative electron capture (REC) into the K-shell of bare xenon to produce tunable and highly linearly polarized X-rays in a storage ring environment (Fig. 1) which we confirmed by a dedicated compton polarimeter.