9 research outputs found
Exploitation of the Timing Capabilities of Metallic Magnetic Calorimeters for a Coincidence Measurement Scheme
In this report, we compare two filter algorithms for extracting timing information using novel metallic magnetic calorimeter detectors, applied to the precision X-ray spectroscopy of highly charged ions in a storage ring. Accurate timing information is crucial when exploiting coincidence conditions for background suppression to obtain clean spectra. For X-rays emitted by charge-changing interactions between ions and a target, this is a well-established technique when relying on conventional semiconductor detectors that offer a good temporal resolution. However, until recently, such a coincidence scheme had never been realized with metallic magnetic calorimeters, which typically feature much longer signal rise times. In this report, we present optimized timing filter algorithms for this type of detector. Their application to experimental data recently obtained at the electron cooler of CRYRING@ESR at GSI, Darmstadt is discussed
Towards an Intrinsic Doppler Correction for X-ray Spectroscopy of Stored Ions at CRYRING@ESR
We report on a new experimental approach for the Doppler correction of X-rays emitted by heavy ions, using novel metallic magnetic calorimeter detectors which uniquely combine a high spectral resolution with a broad bandwidth acceptance. The measurement was carried out at the electron cooler of CRYRING@ESR at GSI, Darmstadt, Germany. The X-ray emission associated with the radiative recombination of cooler electrons and stored hydrogen-like uranium ions was investigated using two novel microcalorimeter detectors positioned under 0â
and 180â
with respect to the ion beam axis. This new experimental setup allowed the investigation of the region of the N, M â L transitions in helium-like uranium with a spectral resolution unmatched by previous studies using conventional semiconductor X-ray detectors. When assuming that the rest-frame energy of at least a few of the recorded transitions is well-known from theory or experiments, a precise measurement of the Doppler shifted line positions in the laboratory system can be used to determine the ion beam velocity using only spectral information. The spectral resolution achievable with microcalorimeter detectors should, for the first time, allow intrinsic Doppler correction to be performed for the precision X-ray spectroscopy of stored heavy ions. A comparison with data from a previous experiment at the ESR electron cooler, as well as the conventional method of conducting Doppler correction using electron cooler parameters, will be discussed
First Experiments with CRYRING@ESR
The low-energy heavy ion storage ring CRYRING was transported from Stockholm to Darmstadt, modernized and reconfigured, and recommissioned as CRYRING@ESR. The machine is now in operation with all installations in service and is available as a user facility for experiments proposed through the SPARC collaboration. During the 2020â2022 period, we brought a number of experimental installations into service and used them to measure first data: the ultra-cold electron cooler for merged-beam electronâion collisions, the gas jet target for atomic collisions, a next-generation microcalorimeter-based X-ray spectroscopy setup, and others. Ions can be injected either in low charge states from a local ion source through a 300 keV/u RFQ linac, or in high charge states from the GSI accelerator chain through ESR. This allows for very broad access to ions across the entire periodic table. CRYRING@ESR is able to de- or accelerate ions and cool and store beams of isotopically pure species in a desired charge state. While the analysis is still largely ongoing, the first experimental data already show that the machine reached its expected performance level, and our high expectations regarding achievable resolution in spectroscopy experiments have been fulfilled. With access to new classes of ions available through ESR injection and a new generation of experimental instrumentation, CRYRING@ESR is a unique facility for experiments with heavy, highly charged ions. Here, we will review our present setup and machine performance, discuss the data from our first commissioning experiments and briefly preview the upcoming new installations for the coming years
Cusp-electron production in collisions of open-shell He-like oxygen ions with atomic targets
Exploitation of the Timing Capabilities of Metallic Magnetic Calorimeters for a Coincidence Measurement Scheme
In this report, we compare two filter algorithms for extracting timing information using novel metallic magnetic calorimeter detectors, applied to the precision X-ray spectroscopy of highly charged ions in a storage ring. Accurate timing information is crucial when exploiting coincidence conditions for background suppression to obtain clean spectra. For X-rays emitted by charge-changing interactions between ions and a target, this is a well-established technique when relying on conventional semiconductor detectors that offer a good temporal resolution. However, until recently, such a coincidence scheme had never been realized with metallic magnetic calorimeters, which typically feature much longer signal rise times. In this report, we present optimized timing filter algorithms for this type of detector. Their application to experimental data recently obtained at the electron cooler of CRYRING@ESR at GSI, Darmstadt is discussed
Exploitation of the Timing Capabilities of Metallic Magnetic Calorimeters for a Coincidence Measurement Scheme
Single and double -shell vacancy production in slow -Xe collisions
We present an experimental and theoretical study of symmetric
collisions at 50, 30, and 15 MeV/u,
corresponding to strong perturbations with = 1.20, 1.55, and
2.20, respectively (: classical -shell orbital velocity, :
projectile velocity), as well as collisions at
15 MeV/u. For each of these systems, x-ray spectra were measured under a
forward angle of with respect to the projectile beam. Target
satellite and hypersatellite radiation, and
, respectively, were analyzed and used to derive
cross section ratios for double-to-single target -shell vacancy production.
We compare our experimental results to relativistic time-dependent two-center
calculations.Comment: 8 pages, 4 figure
[NOCH-AP-Experiment fehlt] X-ray emission associated with radiative recombination for ions at threshold energies
For bare lead ions, decelerated to the low beam energy of 10 MeV/u, the x-ray
emission associated with radiative recombination (RR) at "cold collision"
conditions has been studied at the electron cooler of CRYRING@ESR at
GSI-Darmstadt. Utilizing dedicated x-ray detection chambers installed at
0{\deg} and 180{\deg} observation geometry, we observed for the very first time
for stored ions the full x-ray emission spectrum associated with RR under
electron cooling conditions. Most remarkably, no line distortion effects due to
delayed emission are present in the well resolved spectra, spanning over a wide
range of x-ray energies (from about 5 to 100 keV) which enable to identify
fine-structure resolved Lyman, Balmer as well as Paschen x-ray lines along with
the RR transitions into the K-, L and M-shell of the ions. To compare with
theory, an elaborate theoretical model has been applied. By considering the
relativistic atomic structure of Pb, this model is based on a
sophisticated computation of the initial population distribution via RR for all
atomic levels up to Rydberg states with principal quantum number 165 in
combination with cascade calculations based on time-dependent rate equations.
Within the statistical accuracy, the experimental x-ray line emission is in
very good agreement with the results of the theoretical model applied. Most
notably, this comparison sheds light on the contribution of prompt and delayed
X-ray emission (up to 70 ns) to the observed X-ray spectra, originating in
particular from Yrast transitions into inner shells