Spectroscopy with cold and ultra-cold neutrons

We present two new types of spectroscopy methods for cold and ultra-cold neutrons. The first method, which uses the \RB drift effect to disperse charged particles in a uniformly curved magnetic field, allows to study neutron $\beta$-decay. We aim for a precision on the 10$^{-4}$ level. The second method that we refer to as gravity resonance spectroscopy (GRS) allows to test Newton's gravity law at short distances. At the level of precision we are able to provide constraints on any possible gravity-like interaction. In particular, limits on dark energy chameleon fields are improved by several orders of magnitude.Comment: 3 pages, 2 figures, Proceedings of the Fifteenth International Symposium on Capture Gamma-Ray Spectroscopy and Related Topics (CGS15), TU Dresden, August 25 to August 29, 201

ANNI - A pulsed cold neutron beam facility for particle physics at the ESS

Pulsed beams have tremendous advantages for precision experiments with cold neutrons. In order to minimise and measure systematic effects, they are used at continuous sources in spite of the related substantial decrease in intensity. At the European Spallation Source ESS these experiments will profit from the pulse structure of the source and its 50 times higher peak brightness compared to the most intense reactor facilities, making novel concepts feasible. Therefore, the cold neutron beam facility for particle physics ANNI was proposed as part of the ESS instrument suite. The proposed design has been re-optimised to take into account the present ESS cold moderator layout. We present design considerations, the optimised instrument parameters and performance, and expected gain factors for several reference experiments.Comment: 8 pages, 4 figures; submitted to the Proceedings of the International Workshop on Particle Physics at Neutron Sources PPNS 2018, Grenoble, France, May 24-26, 201

Procalcitonin as marker of infection in patients with Goodpasture's syndrome is misleading

Abstract Background. Procalcitonin (PCT) is routinely measured to differentiate autoimmune disorders from infection. There are reports, however, where PCT is high in the absence of infection, i.e. in vasculitis. To investigate the value of PCT in Goodpasture's syndrome, we reviewed the charts of patients with Goodpasture's syndrome who were treated from 1996 to 2006. Methods. PCT (normal range <0.5 ng/ml) was measured with an immunoluminometric assay, C-reactive protein (CRP; normal range <5 mg/l) with nephelometry. Anti-glomerular basement membrane antibodies (normal range <1:10) were measured with ELISA

First Results for the pLGAD Sensor for Low-Penetrating Particles

Silicon sensors are the go-to technology for high-precision sensors in particle physics. But only recently low-noise silicon sensors with internal amplification became available. The so-called Low Gain Avalanche Detector (LGAD) sensors have been developed for applications in High Energy Physics, but lack two characteristics needed for the measurement of low-energy protons (<60 keV): a thin entrance window (in the order of tens of nm) and the efficient amplification of signals created near the sensor's surface (in a depth below 1 um). In this paper we present the so-called proton Low Gain Avalanche Detector (pLGAD) sensor concept and some results from characterization of the first prototypes of the sensor. The pLGAD is specifically designed to detect low-energy protons, and other low-penetrating particles. It will have a higher detection efficiency than non-silicon technologies, and promises to be a lot cheaper and easier to operate than competing silicon technologies.Comment: 5 pages, 5 figuures, VCI 202

A short isoform of STIM1 confers frequency-dependent synaptic enhancement

Store-operated Ca2+-entry (SOCE) regulates basal and receptor-triggered Ca2+ signaling with STIM proteins sensing the endoplasmic reticulum (ER) Ca2+ content and triggering Ca2+ entry by gating Orai channels. Although crucial for immune cells, STIM1’s role in neuronal Ca2+ homeostasis is controversial. Here, we characterize a splice variant, STIM1B, which shows exclusive neuronal expression and protein content surpassing conventional STIM1 in cerebellum and of significant abundance in other brain regions. STIM1B expression results in a truncated protein with slower kinetics of ER-plasma membrane (PM) cluster formation and ICRAC, as well as reduced inactivation. In primary wild-type neurons, STIM1B is targeted by its spliced-in domain B to presynaptic sites where it converts classic synaptic depression into Ca2+- and Orai-dependent short-term synaptic enhancement (STE) at high-frequency stimulation (HFS). In conjunction with altered STIM1 splicing in human Alzheimer disease, our findings highlight STIM1 splicing as an important regulator of neuronal calcium homeostasis and of synaptic plasticity

Design of the Magnet System of the Neutron Decay Facility PERC

The PERC (Proton and Electron Radiation Channel) facility is currently under construction at the research reactor FRM II, Garching. It will serve as an intense and clean source of electrons and protons from neutron beta decay for precision studies. It aims to contribute to the determination of the Cabibbo-Kobayashi-Maskawa quark-mixing element $V_{ud}$ from neutron decay data and to search for new physics via new effective couplings. PERC's central component is a 12m long superconducting magnet system. It hosts an 8m long decay region in a uniform field. An additional high-field region selects the phase space of electrons and protons which can reach the detectors and largely improves systematic uncertainties. We discuss the design of the magnet system and the resulting properties of the magnetic field.Comment: Proceedings of the International Workshop on Particle Physics at Neutron Sources PPNS 2018, Grenoble, France, May 24-26, 201