Related papers: Optimizing neutron moderators for a spallation-dri…
We present the first measurements of the survival time of ultracold neutrons (UCNs) in solid deuterium SD2. This critical parameter provides a fundamental limitation to the effectiveness of superthermal UCN sources that utilize solid…
A novel cold neutron source (CNS) employing chessboard or staircase assemblies of high-aspect ratio rectangular (HARR) para-hydrogen (p-H2) moderators is proposed. It is demonstrated that this design can generate neutron beams with higher…
The TUCAN (TRIUMF Ultra-Cold Advanced Neutron) collaboration aims to search for the neutron electric dipole moment (nEDM) with unprecedented precision. One of the essential elements for the nEDM measurement is a polarization analyzer of…
The work presented in this thesis forms part of a program at the Paul Scherrer Institute (PSI) to construct a high intensity superthermal ultra-cold neutron (UCN) source based on solid deuterium as UCN production medium. We carried out a…
We consider cooling of neutron stars (NSs) with superfluid cores composed of neutrons, protons, and electrons (assuming singlet-state pairing of protons, and triplet-state pairing of neutrons). We mainly focus on (nonstandard) triplet-state…
The puzzle remains in the large discrepancy between neutron lifetime measured by the two distinct experimental approaches -- counts of beta decays in a neutron beam and storage of ultracold neutrons in a potential trap, namely, the beam…
We describe a helium evaporation refrigerator used to cool dynamically polarized proton and deuteron targets for electron-scattering experiments using the CEBAF Large Acceptance Spectrometer CLAS12 at Jefferson Lab. The geometry of the…
We investigate the possibility of ultracold neutron (UCN) storage in quantum states defined by the combined potentials of the Earth's gravity and the neutron optical repulsion by a horizontal surface of liquid helium. We analyse the…
Improved accessibility to the microkelvin temperature regime is important for future research in quantum materials; for quantum information science; and for applications of quantum sensors. Here we report the design and performance of a…
Transport calculations for neutronic design require accurate nuclear data and validated computational tools. In the Spallation Physics Group, at the European Spallation Source, we perform shielding and neutron beam calculations to help the…
A new type of cold/ultracold neutron detector that can realize a spatial resolution of less than 100 nm was developed using nuclear emulsion. The detector consists of a fine-grained nuclear emulsion coating and a 50-nm thick $^{10}$B$_4$C…
The properties of superdense matter in neutron star (NS) cores control NS thermal states by affecting the efficiency of neutrino emission from NS interiors. To probe these properties we confront the theory of thermal evolution of NSs with…
The neutron time-of-flight (n_TOF) facility at the European Laboratory for Particle Physics (CERN) is a pulsed white-spectrum neutron spallation source producing neutrons for two experimental areas: the Experimental Area 1 (EAR1), located…
We report the first measurement of angular correlation parameters in neutron $\beta$-decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for $\sim 30$ s in a Cu decay…
Our recent neutron scattering measurements of phonons and magnons in solid \alpha-oxygen have led us to a new understanding of the production mechanismen of ultra-cold-neutrons (UCN) in this super-thermal converter. The UCN production in…
Thermoluminescence detectors (TLD) were used for dose measurements at JET. Several hundreds of LiF detectors of various types, standard LiF:Mg,Ti and highly sensitive LiF:Mg,Cu,P were produced. LiF detectors consisting of natural lithium…
The Neutrinos from Stored Muons, nuSTORM, facility has been designed to deliver a definitive neutrino-nucleus scattering programme using beams of ,{\nu}e- and ,{\nu}{\mu}- from the decay of muons confined within a storage ring. The facility…
This study investigates the moderation of 14.1 MeV neutrons in a natural beryllium moderator arranged in a spherical geometry. The neutron interactions and moderation efficiency were analyzed using Monte Carlo simulations with the GEANT4…
Current state-of-the-art superconducting microwave qubits are cooled to extremely low temperatures to avoid sources of decoherence. Higher qubit operating temperatures would significantly increase the cooling power available, which is…
We present experimental measurements of the properties of a liquid "Fomblin" surface obtained by the quasielastic scattering of laser light. The properties include the surface tension and viscosity as a function of temperature. The results…