UCN, the ultracold neutron source -- neutrons for particle physics

Ultracold neutrons provide a unique tool for the study of neutron properties. An overview is given of the ultracold neutron (UCN) source at PSI, which produces the highest UCN intensities to fundamental physics experiments by exploiting the high intensity proton beam in combination with the high UCN yield in solid deuterium at a temperature of 5 K. We briefly list important fundamental physics results based on measurements with neutrons at PSI.

Final results for the neutron β-asymmetry parameter A0 from the UCNA experiment

The UCNA experiment was designed to measure the neutron β-asymmetry parameter A0 using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7 T magnetic field, and then directed to a 1 T solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for A0 was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008–2009, 2010, and 2011–2013, which ultimately culminated in a 0.67% precision result for A0.

Energy distribution of μd1s muonic atom and its spin states effecting on muonic X-Ray transfer yield in solid thin film method

We have investigated the energy distribution of [Formula: see text] and its spin states (F) effecting on muonic X-ray transfer yield in the solid thin film method. Argon ( Ar ) ion has been considered as the implanted ion in solid deuterium (s D 2) layer at a temperature of T = 3 K. A kinetics model has been used, the corresponding rate equations have been constructed and our results of X-ray yield have been compared with recent measured data. The μd1s muonic atoms, which can take part in resonant molecular formation, have been separated from atoms participating in nonresonant reactions. On this basis, the integrated number of X-rays has been calculated. The results show that the effect of μd1s energy distribution on the number of X-photons is not serious, while its spin states strongly affect the muonic X-ray yield.