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 0∘ and 180∘ with respect to the ion beam axis. This new experimental setup allowed the investigation of the region of the N, M → 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

Anwendung kryogener Kalorimeter für hoch aufgelöste Präzisions-Röntgenspektroskopie

Im Rahmen dieser Arbeit wurde die in den letzten Jahren stetig weiterentwickelte Technologie der metallischen magnetischen Mikrokalorimeter für den Einsatz als Hochpräzisionsspektrometer in der Atomphysik vorbereitet. Diese Detektoren vereinen aufgrund ihres einzigartigen Funktionsprinzips Vorteile verschiedener konventioneller energiedispersiver Photonennachweistechnologien. Sie verbinden die breite spektrale Akzeptanz von Halbleiterdetektoren mit der hohen Auflösung von Kristallspektrometern und stellen damit ein ideales Werkzeug für die Vermessung atomphysikalischer Interaktion mit einem breiten Bereich von Photonenenergien dar. Um das volle Potential der Detektoren ausnutzen zu können, wird jedoch der Übergang von einer für die konventionellen Verfahren etablierten analogen auf eine digitale Signalanalyse benötigt. Daher wurde im Verlauf der Arbeit ein leistungsfähiges und umfangreiches Softwarepaket entwickelt, um die Daten mehrerer durchgeführter Experimente auswerten zu können. Zum einen wurden Röntgenübergänge von Barium und Eisen an der S-EBIT-I beobachtet und identifiziert. Zum anderen wurden am internen Gasjet-Target des ESR-Speicherrings der GSI sowohl die 1s-Lamb-Verschiebung von Xe53+ als auch die 2s-Lamb-Verschiebung von Xe89+ erfolgreich mit Mikrokalorimeterdetektoren vermessen. Es konnten sowohl auf technischer Ebene als auch konzeptionell für den Betrieb und das Messprozedere signifikante Verbesserungen erzielt werden, sodass metallische magnetische Mikrokalorimeter für zukünftige Hochpräszisionsexperimente der Atomphysik bereitstehen

X-ray Spectroscopy Based on Micro-Calorimeters at Internal Targets of Storage Rings

With metallic-magnetic calorimeters (MMCs), promising detectors for high-precision X-ray spectrometry in atomic and fundamental physics experiments are available. In this work, we present a pilot experiment based on a maXs-30 type MMC-spectrometer for recording X-rays emitted in collisions of lithium-like uranium ions with a molecular nitrogen gas jet in the internal target of the ESR storage ring of the GSI. Sample spectra have been measured, and a multitude of X-ray transitions have been unambiguously identified. As a first test and for comparison with data recorded at an EBIT, the 2s Lamb shift in lithium-like uranium was estimated

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