Microcalorimeters for X-Ray Spectroscopy of Highly Charged Ions at Storage Rings

Abstract

X-ray spectroscopy of highly charged heavy ions is an important tool for the investigation of many topics in atomic physics. Such highly charged ions, in particular hydrogen-like uranium, are investigated at heavy ion storage rings, where high charge states can be produced in large quantities, stored for long times and cooled to low momentum spread of the ion beam. One prominent example is the determination of the 1s Lamb Shift in hydrogen-like heavy ions, which has been investigated at the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre for Heavy Ion Research. Due to the large electron binding energies, the energies of the corresponding photon transitions are located in the X-ray regime. To determine the transition energies with high accuracy, highly resolving X-ray spectrometers are needed. One concept of such spectrometers is the concept of microcalorimeters, which, in contrast to semiconductor detectors, uses the detection of heat rather than charge to detect energy. Such detectors have been developed and successfully applied in experiments at the ESR. For experiments at the Facility for Antiproton and Ion Research (FAIR), the Stored Particles and Atoms Collaboration (SPARC) pursues the development of new microcalorimeter concepts and larger detector arrays. Next to fundamental investigations on quantum electrodynamics such as the 1s Lamb Shift or electron–electron interactions in two- and three-electron systems, X-ray spectroscopy may be extended towards nuclear physics investigations like the determination of nuclear charge radii.

High-precision calculations of the $1s^{2} 2s 2p$ $^1P_{1} \to 1s^{2} 2s^{2}$ $^1S_{0}$ spin-allowed $E1$ transition in C {\small III}

“…Two important and complementary properties of atomic states are transition energies and transition rates. For transition energies, the present experimental accuracy reaches the order of 10 −6 − 10 −18 [1][2][3]. For this case the interplay between experiment and theory has improved drastically our understanding of different effects, e.g., the Breit interaction, finite nuclear mass, and quantum electrodynamics (QED) effects [4,5].…”

Integration of maXs-type microcalorimeter detectors for high-resolution x-ray spectroscopy into the experimental environment at the CRYRING@ESR electron cooler

“…SPARC focuses on research in the realm of atomic, quantum, and fundamental physics at GSI and FAIR 7 , with a particular focus on precision x-ray spectroscopy. Within the collaboration, two microcalorimeter designs have recently been developed, namely the SIM-X detector [27], which is based on a compensated-doped silicon thermistor, and the maXs detector (Micro-Calorimeter Arrays for High Resolution x-ray Spectroscopy, [28]), which is a magnetic microcalorimeter (MMC). An overview of the recent progress of these activities is presented in [29].…”

Integration of maXs-type microcalorimeter detectors for high-resolution x-ray spectroscopy into the experimental environment at the CRYRING@ESR electron cooler

“…Within the collaboration, two microcalorimeter designs have been recently developed, namely the SIM-X detector [25], which is based on a compensated-doped silicon thermistor, and the maXs detector (Micro-Calorimeter Arrays for High Resolution X-ray Spectroscopy, [26]), which is a magnetic microcalorimeter (MMC). An overview of the recent progress of these activities is presented in [27]. In particular, prototypes of both detector systems have been successfully deployed in recent test experiments at the gas jet target of the ESR at GSI [28,29].…”