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Alexander Wolfertz

Publications and source records attributed to Alexander Wolfertz.

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High Temporal and Spatial Resolution X-Ray and Gamma-Ray Imaging using an Event-Mode Scintillator-Based Detector

LumaCam detectors are a novel type of event-mode imaging detectors based on scintillator screens that have been developed recently for neutron imaging applications. They operate in an event-mode in which individual interactions of the incoming particles with the scintillator screen are reconstructed in both space and time, providing simultaneous high spatial and temporal resolution. In this work, we demonstrate the applicability of LumaCam detectors to X-ray and gamma-ray imaging. First tests with a 120 kV acceleration voltage X-ray source show a spatial detector resolution down to 50 um and the temporal resolution is estimated to be ~1 us. This combination makes LumaCam detectors especially suitable for imaging fast processes with high spatial resolution with limited cone beam magnification. The most significant adaption of the detector from the version for neutron detection is the scintillator screen. To further investigate the potential of LumaCam detectors for high-energy photon applications, additional measurements employing different scintillator screen materials have been carried out using gamma ray sources. The results show significant improvements in the temporal resolution with values as low as ~15 ns. In addition, some scintillators also show significant energy sensitivity in the photon multiplicity spectrum, highlighting the potential of LumaCam detectors for energy-selective X-ray and gamma-ray imaging.

physics.ins-det

Cavity-mediated coherent coupling between distant quantum dots

Scalable architectures for quantum information technologies require to selectively couple long-distance qubits while suppressing environmental noise and cross-talk. In semiconductor materials, the coherent coupling of a single spin on a quantum dot to a cavity hosting fermionic modes offers a new solution to this technological challenge. Here, we demonstrate coherent coupling between two spatially separated quantum dots using an electronic cavity design that takes advantage of whispering-gallery modes in a two-dimensional electron gas. The cavity-mediated long-distance coupling effectively minimizes undesirable direct cross-talk between the dots and defines a scalable architecture for all-electronic semiconductor-based quantum information processing.

cond-mat.mes-hall