Rare-earth oxihydrides show a reversible photochromic effect, whereas the details of the underlying mechanism are not yet fully understood. A major influence on properties such as band gap, electrical conductivity, or light absorption is achieved by modifying the chemical composition, i.e. the O$^{2-}$ and H$⁻$ content of the material. Recently published results of PALS measurements performed...
To measure the gravitation pull on Antimatter, the AEgIS collaboration at CERN aims to perform moiré deflectometry on a beam of cold Antihydrogen. For such a measurement to be sufficiently accurate, the resulting fringe pattern needs to be resolved with micrometric accuracy. Here we present the technology and design considerations behind the OPHANIM detector, a purpose built Antihydrogen...
Depth resolved positron annihilation Doppler-broadening spectroscopy (DBS) at
the top-most atomic layer of solid materials is a fundamental but largely
unexplored field of research. This is because it requires monoenergetic
positron beams with energies in the order of only a few of eV.
SLOPE (Setup for LOw-energy Positron Experiments) is specially designed for
a low energy beam, enabling...
Doppler Broadening Spectroscopy (DBS) of the positron electron annihilation line allows the analysis of defects inside materials. DBS uses the fact that during the annihilation momentum has to be conserved and is therefore transferred to the annihilation gammas. As a sufficient approximation the positron is assumed to be thermalized in the solid when it annihilates with an electron. In that...
I will review the main works done in the last years by my research group in collaboration with the researchers of NEPOMUC. These works include studies on vacancy like defects in silicon based materials, oxides, materials for hydrogen storage and soft matter.
At the light of the obtained results I will discuss the experimental requirements for a new class of measurements in material science at NEPOMUC.
Many instabilities common to magnetized ion-electron plasmas are expected to be absent or suppressed in electron-positron "pair" plasmas. APEX (A Positron Electron eXperiment) aim to create and confine a low-energy pair plasma by combining non-neutral plasmas of electrons and positrons in a purely magnetic trap [1]. A significant challenge associated with this task is the accumulation and...
Pulsed low-energy positron beams of variable energy are powerful
tools for defect profiling in materials with positron annihilation lifetime spectroscopy (PALS). The UniBwM operates two pulsed positron beams at NEPOMUC: The Pulsed Low-Energy Positron System (PLEPS) for depth-resolved (1D-)defect profiling and the Scanning Positron Microscope (SPM), which in addition offers lateral micrometer...
The AEgIS experiment at CERN aims to measure the acceleration of cold antimatter in earth's gravity field by determining the vertical displacement of the beam. An important part of the experimental setup is a detector, that can determine the position of the antimatter particles. For this purpose, the Ophanim detector - a CMOS sensor with 3.85 billion pixels - is developed.
In order to...
The metal halide perovskites (MHPs) are attracting intense research interest due to their excellent optoelectronic properties. The all-inorganic member CsPbBr$_3$ is of particular interest for gamma-ray detector applications and LEDs. Further, single crystals can be grown via a solution route or by a melt process, and thin films can be solution processed or produced by vapour deposition....
