0000000000144514
AUTHOR
C. Plonka
Search for an electric charge of the neutron
The electrical neutrality of the neutron is linked to the electric charge quantization. It is not understood yet if the electric charge is quantized or not. Since the discovery of the neutron, many attempts have been made to measure its electric charge ${q}_{n}$ directly and indirectly. We present a method to search for a possible ${q}_{n}$ by means of an optical setup using ultracold neutrons. In a first run, a statistical sensitivity of $\ensuremath{\delta}{q}_{n}=2.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}20}\text{ }\text{ }e/\sqrt{\mathrm{day}}$ is achieved. Possible improvements to increase this sensitivity down to $\ensuremath{\delta}{q}_{n}\ensuremath{\approx}1\ifmmode\…
A measurement of the antineutrino asymmetry B in free neutron decay
Abstract We have measured the antineutrino asymmetry B in neutron beta decay, i.e., the correlation of the neutron spin and the antineutrino momentum, with a new method. Our result is B = 0.967 ± 0.006 stat ± 0.010 syst = 0.967 ± 0.012 . Statistical and systematic uncertainty can be considerably reduced in future experiments.
Determination of impurity distributions in ingots of solar grade silicon by neutron activation analysis
AbstractIn a series of crystallization experiments, the directional solidification of silicon was investigated as a low cost path for the production of silicon wafers for solar cells. Instrumental neutron activation analysis was employed to measure the influence of different crystallization parameters on the distribution of 3d-metal impurities of the produced ingots. A theoretical model describing the involved diffusion and segregation processes during the solidification and cooling of the ingots could be verified by the experimental results. By successive etching of the samples after the irradiation, it could be shown that a layer of at least 60 μm of the samples has to be removed to get r…
Transmission of very slow neutrons through material foils and its influence on the design of ultracold neutron sources
At the Paul Scherrer Institute (PSI), a very intense source of ultracold neutrons (UCN) is being built. The UCN converter of solid deuterium must be contained in a vessel. Produced UCN leave that vessel through its top lid. To decide on the design of the vessel and the top lid, we have measured the transmission of neutrons with velocities between 3 and 20 m/s through different material foils. Contrary to expectations, we found that transmission through aluminium and aluminium alloys is equal or even higher compared to zirconium and reactor-grade zirconium alloys, respectively.