arXiv subjects

Bastian Löher

Publications and source records attributed to Bastian Löher.

3 recordsLinked to original sources

arXiv2026

Compact VMM3a/SRS integration for high-channel-density TPC readout

The HYDRA (HYpernuclei Decay at R$^3$B Apparatus) TPC is a 5,376-channel pion tracker developed for hypernuclear studies at the R$^3$B experiment at GSI/FAIR. Its installation inside the GLAD dipole magnet imposes strict space constraints above the pad plane. To fit the front-end electronics within this volume, the VMM3a/SRS readout was adapted through a vertical hybrid arrangement and custom boards for signal routing and power distribution. At the same time, the readout had to be integrated with the R$^3$B timing system, which is not natively supported by the SRS. This was achieved by recording the R$^3$B heimtime and trigger signals through spare VMM3a channels, allowing the global timestamps to be reconstructed from the same data stream. Simulations of the PCB coupling indicated low crosstalk between adjacent traces, while S-curve measurements gave a baseline noise level consistent with that reported for the standard VMM3a/SRS readout. Cosmic-muon measurements with the plastic wall provided reconstructed tracks and confirmed event-by-event timing correlation between the two detector systems.

physics.ins-det↗

arXiv2024

Quantum Electrodynamics in Strong Electromagnetic Fields: Substate Resolved K$α$ Transition Energies in Helium-like Uranium

Using novel metallic magnetic calorimeter detectors at the CRYRING@ESR, we recorded X-ray spectra of stored and electron cooled helium-like uranium (U$^{90+}$) with an unmatched spectral resolution of close to 90 eV. This allowed for an accurate determination of the energies of all four components of the K$α$ transitions in U$^{90+}$. We find good agreement with state-of-the-art bound-state QED calculations for the strong-field regime. Our results do not support any systematic deviation between experiment and theory in helium-like systems, the presence of which was subject of intense debates in recent years.

physics.atom-ph↗

arXiv2013

The high-efficiency γ-ray spectroscopy setup γ3 at HIγS

The existing Nuclear Resonance Fluorescence (NRF) setup at the HIγS facility at the Triangle Universities Nuclear Laboratory at Duke University has been extended in order to perform γ-γ coincidence experiments. The new setup combines large volume LaBr3:Ce detectors and high resolution HPGe detectors in a very close geometry to offer high efficiency, high energy resolution as well as high count rate capabilities at the same time. The combination of a highly efficient γ-ray spectroscopy setup with the mono-energetic high-intensity photon beam of HIγS provides a worldwide unique experimental facility to investigate the γ-decay pattern of dipole excitations in atomic nuclei. The performance of the new setup has been assessed by studying the nucleus \sulfur at 8.125 MeV beam energy. The γ-decay branching ratio from the $1^+$ level at 8125.4 keV to the first excited $2^+$ state was determined to 15.7(3)%.

physics.ins-det↗