arXiv subjects

D. Salazar

Publications and source records attributed to D. Salazar.

7 recordsLinked to original sources

arXiv2026

A New High-Intensity Source for Ultracold Neutrons

The TRIUMF UltraCold Advanced Neutron (TUCAN) collaboration has completed a new superthermal source for ultracold neutrons (UCNs) at TRIUMF. It uses neutrons from a spallation target driven by TRIUMF's %520-MeV main cyclotron. Heavy water and liquid deuterium serve as neutron moderators, and inelastic scattering inside superfluid $^4$He at around \qty{1.1}{\kelvin} slows the neutrons down to become ultracold. During commissioning runs with the completed source, including the deuterium moderator, up to $1.47(2)\times 10^7$ UCNs were detected in the experimental area after irradiating the target and accumulating UCNs in the source for \qty{60}{\second}. Up to \qty{6.75(3)e5} UCN/s were detected during continuous operation, more than at any other source in the world.

physics.ins-det↗

arXiv2025

Ultracold Neutron Guide-Coating Facility at U.Winnipeg

We report the construction and commissioning of a new ultracold neutron (UCN) guide-coating facility at the University of Winnipeg. The facility employs pulsed laser deposition (PLD) to produce diamond-like carbon (DLC) coatings on cylindrical UCN guides up to 1 m in length with a 200 mm outer diameter. DLC is a promising material for UCN transport and storage due to its high real component of the optical potential, low neutron absorption cross section, and low depolarization probabilities. First coating attempts on a full length aluminum UCN guide and matching blank flange were successfully coated with a carbon film with density of 2.3 g/cm$^3$, corresponding to optical potentials of 200 neV, as measured by X-ray reflectometry (XRR). Coating thicknesses were measured to be 90 nm for the UCN guide and 180 nm for the flange with no evidence of delamination. The implementation of a plasma plume collimator and plasma feed back control via a time of flight in vacuum ion probe produced a film with an XRR measured density of 2.8 g/cm$^3$, corresponding to an optical potential of 240 neV. This 80 nm thick film had poor adhesion to the aluminum tube substrate. These results establish a baseline for the coating facility. Ongoing and future work focuses on improving the diamond content of films and adhesion through plasma plume collimation, TOF ion probe feed back, and pre/post treatment methods with the goal of providing high quality DLC UCN guides for the TUCAN experiment at TRIUMF.

physics.ins-det↗

arXiv2025

Initial results of the TRIUMF ultracold advanced neutron source

We report the first results on ultracold neutron production from a new spallation-driven superfluid $^4$He (He-II) source at TRIUMF, which is being prepared for a new, precise measurement of the neutron electric dipole moment. A total of $(9.3 \pm 0.8)\times 10^{5}$ ultracold neutrons were observed at a proton beam current of \SI{37}{\uA}, when the target was irradiated for a period of \SI{60}{\s}. The results are in fair agreement with expectations based on a detailed simulation of neutron transport and ultracold neutron source cryogenics. There is some indication that the new source might not be as limited by the conduction of heat through the He-II as originally expected. The results indicate that the source is likely to make its ultimate production goals, once the liquid deuterium cold moderator system is completed, with the expectation that $5.7\times 10^7$~UCNs would be detected in the same experiment with full liquid levels. This would, for example, correspond to delivery of $1.4\times 10^6$~UCNs delivered to each of two nEDM measurement cells, and a statistical uncertainty of $1\times 10^{-27}~e$cm on the neutron EDM in 280 days of running.

nucl-ex↗

arXiv2025

Neutron EDM Experiment with an Advanced Ultracold Neutron Source at TRIUMF

The TRIUMF Ultracold Advanced Neutron (TUCAN) collaboration has been developing a high-intensity ultracold neutron (UCN) source aimed at searching for the neutron electric dipole moment (EDM) with a sensitivity goal of $10^{-27}\ e{\rm cm}$. This article reports on recent progress in commissioning of the UCN source and in the development of the neutron EDM spectrometer. In its final configuration, the accelerator-driven super-thermal UCN source will enable a neutron EDM experiment with two orders of magnitude improved statistics compared to the current best experiment. Substantial progress in 2024 allowed the collaboration to operate the complete source system, with the exception of the liquid deuterium cold moderator, resulting in the first production of UCNs. The status of the EDM spectrometer is also presented, with emphasis on UCN handling components and magnetic subsystems relevant to field control, shielding, and magnetometry.

physics.ins-det↗

arXiv2019

Database of novel magnetic materials for high-performance permanent magnet development

This paper describes the open Novamag database that has been developed for the design of novel Rare-Earth free/lean permanent magnets. The database software technologies, its friendly graphical user interface, advanced search tools and available data are explained in detail. Following the philosophy and standards of Materials Genome Initiative, it contains significant results of novel magnetic phases with high magnetocrystalline anisotropy obtained by three computational high-throughput screening approaches based on a crystal structure prediction method using an Adaptive Genetic Algorithm, tetragonally distortion of cubic phases and tuning known phases by doping. Additionally, it also includes theoretical and experimental data about fundamental magnetic material properties such as magnetic moments, magnetocrystalline anisotropy energy, exchange parameters, Curie temperature, domain wall width, exchange stiffness, coercivity and maximum energy product, that can be used in the study and design of new promising high-performance Rare-Earth free/lean permanent magnets. The results therein contained might provide some insights into the ongoing debate about the theoretical performance limits beyond Rare-Earth based magnets. Finally, some general strategies are discussed to design possible experimental routes for exploring most promising theoretical novel materials found in the database.

cond-mat.mtrl-sci↗

arXiv2017

Multispike solutions for the Brezis-Nirenberg problem in dimension three

We consider the problem $Δu + λu +u^5 = 0$, $u>0$, in a smooth bounded domain $Ω$ in ${\mathbb R}^3$, under zero Dirichlet boundary conditions. We obtain solutions to this problem exhibiting multiple bubbling behavior at $k$ different points of the domain as $λ$ tends to a special positive value $λ_0$, which we characterize in terms of the Green function of $-Δ- λ$.

math.AP↗

arXiv2013

Phase transition in a super superspin glass

We here confirm the occurrence of spin glass phase transition and extract estimates of associated critical exponents of a highly monodisperse and densely compacted system of bare maghemite nanoparticles. This system has earlier been found to behave like an archetypal spin glass, with e.g. a sharp transition from paramagnetic to non-equilibrium behavior, suggesting that this system undergoes a spin-glass phase transition at a relatively high temperature, $T_g$ $\sim$ 140 K.

cond-mat.dis-nn↗