SPARC Topical Workshop 2016

The collision of highly charged, heavy ions with atomic or molecular gas targets or free electrons causes a variety of reactions such as electronic excitation, ionization, radiative electron capture and, in the case of molecules, dissociation. After such a highly energetic reaction, these targets remain in superexcited electronic states which themselves may decay via fluorescence,...

Dielectronic recombination (DR) has been developed as a powerful spectroscopic tool for study of highly charged ions (HCI). The newly twin-electron-beam technique invented at the TSR leads to a significant improvement of the DR experimental energy resolution. The electron beams created from a separate ultra-cold electron target can be much colder as compared to electron-beam produced from the...

One of the goals of Helmholtz Institute Jena with respect to the Facility for Antiproton and Ion Research is to provide highly charged, low-energy ions by using the S-EBIT facility currently being installed at GSI [1]. This is of particular importance during the FAIR construction related shutdown period of the GSI accelerator complex, when little to no beam time can be provided. During...

The secondary electron emission from nucleobases and water is an important topic in the contemporary atomic collision physics. Highly charged ion induced ionization, radical emission following fragmentation are important mechanisms in the study of radiation-damage which will have applications in case of hadron therapy. In the present study, the collision energies are made to vary across the...

Molecular dimers widely exist in planetary atmosphere, and play an important role in molecular and surface physics, astrophysics, and climate. The N2Ar dimer is a typical molecular complex of Ar with N2, which is particularly relevant to the atmosphere of Titan. In the present work, the 1 MeV Ne^{8+} ions were used to produce the (N2Ar)^{3+} ions, the momenta of fragment ions of three-body...

The HILITE experiment is designed to produce well-defined ion targets, specifically of highly charged ions, and to make them available for studies at high-intensity lasers. It features a cryogenic Penning trap and methods to control the ion cloud composition, size, shape, position and density. Educts and products of the ion-laser interaction can be studied destructively and non-destructively,...

The well-known existing disparity between the interaction range and the coupling constant for the electromagnetic and the strong force suggests independent treatment of atomic and nuclear phenomena. However, the borderline between atomic and nuclear physics i.e. Coulomb barrier region provides an interesting playground for many basic nuclear and atomic processes which mutually influence each...

The photon induced K shell x-ray intensity ratios and the satellite spectra of chlorine are investigated. Unlike conventional use of crystal spectrometers, the satellite x-ray structure is observed using energy dispersive spectrometer with high resolution silicon drift detector and x-ray tube as photon source. The energy shift of chlorine KL1 line from the KL0 position is also measured and...

The focusing properties of two-stage (tandem) ideal parallel plate mirror analyzer (PPA) are investigated both analytically using Mathematica [1] and in simulations using SIMION [2]. Both U and S arrangements [3] for 45 and 30 dgrs tandems are investigated for 1st and 2nd order focusing conditions, energy dispersion, trace width, overall transmission and detection solid angle. The effect of a...

The combination of advanced lasers and heavy ion storage rings provides a novel research platform for atomic physics and nuclear physics of highly charged ions (HCI). Laser cooling of highly charged heavy ion beams could reach a much lower momentum spread and much faster cooling speed as compared to electron-cooling and stochastic-cooling. Laser cooling is also considered as one of the most...

Investigation of the g factor is one of the most accurate tools for testing physical theories and for determination of fundamental constants. Considerable progress was made recently with experiments with light ions. Moving to the high-Z sector potentially gives new opportunities for precision investigations of the atomic g factor. Further research in this field requires rigorous theoretical...

The combined field of heavy ion and strong laser pulse can be used to produce the electron-positron pairs from the vacuum. This process gives an opportunity for testing QED effects in non-perturbative regime. For experimental investigation of such effects one can use the relativistic ion beam with a strong laser source. The large Lorentz factor leads to to the enhancement of laser power and...

The PEGASUS project at GSI aims at providing an intense and portable spin-polarized electron beam for experiments in crossed- and merged-beams arrangements at various ion-beam facilities. Electron energies will range from 1 to 10 keV at electron currents up to 100 μA. Laser induced electron emission from GaAs photocathodes with a state of negative electron affinity will be utilized for beam...

We investigate the polarization entanglement of two photons emitted in the atomic processes with few-electron ions. All results have been obtained within the framework of the density matrix approach and relativistic quantum theory. We consider two different schemes. In the first one the initial state is the state with well-defined angular momentum and its projection onto the quantization axis....

High-precision measurements of the isotope shifts in heavy ions, that are anticipated at the FAIR facilities, will give a unique possibility for tests of QED in a new region: strong-coupling regime beyond the Furry picture. In addition, these studies will allow determination of the nuclear charge radius differences for radioactive isotopes with a lifetime longer than about 1 min. These...

The purpose of the present work is to obtain a simple expression for estimation of the probability of K-shell ionization in heavy ion collisions. The transition amplitudes was calculated numerically and approximated by a simple analytical expression. It allows obtaining the process probability in a closed analytic form as well. In the present work we focus on the case of asymmetric...

The Frankfurt Low Energy Storage Ring (FLSR)[1] is an electrostatic storage ring at Institut für Kernphysik, Goethe Universität, Frankfurt am Main, Germany. It has been installed as a novel tool for experiments of the reaction dynamics of vibrational cool molecular ions. First beam was stored in 2013. Since then a number of ions/molecules has been stored. First experiments on dissociative...

To cool ion beams in the heavy ion storage ring CRYRING and thus achieve a low momentum spread, CRYRING features an electron cooler, where the ion beam is superimposed with a monoenergetic electron beam. In order to calculate the velocity of the electrons and therefore of the cooled ion beam, it is mandatory to continously monitor the cooler voltage with a high-precision divider. For that...

In the present work critical distances for homonuclear quasi-molecules are calculated for a range of point-like and extended nuclei with 85 < Z < 100. High-precision relativistic calculations of the ground-state energy of molecular ions with charges Z = 1, 2, 10, 20, 30, 40, 50, 60, 70, 80, 90, 92, 100 at ``chemical distances''R = 2/Z (in a.u.) were executed. To solve the two-centered Dirac...

The study of heavy-ion systems at the GSI Helmholtz-center for Heavy-Ion Research in Darmstadt has proven to provide a deep insight into atomic structures and interactions processes in the presence of extreme field-strengths [1]. The FAIR project which is currently being built at the site of the GSI and especially its High-Energy Storage Ring (HESR) give raise to new opportunities for...

Highly charged heavy ions provide a unique possibility to test atomic structure calculations. We would like to study effects of electron-electron correlations in Be-like krypton via a laser spectroscopy measurement of the fine-structure transition from the metastable 3P0 state. For this purpose the ions are stored at β=0.69 in the Experimental Storage Ring (ESR) where the transition to the 3P1...

As a result of cooperative theoretical and experimental research of the g-factor of light highly charged ions, the best up-to-date determination of the electron mass was provided [1]. It's expected that independent determination of the fine structure constant will be the result of the corresponding investigations of heavy hydrogen-like and boron-like ions [2,3]. The ARTEMIS experiment is an...