A5066212291- Particle accelerators and beam dynamics
- Muon and positron interactions and applications
- Superconducting Materials and Applications
- Gyrotron and Vacuum Electronics Research
- Plasma Diagnostics and Applications
- Physics of Superconductivity and Magnetism
- Particle Accelerators and Free-Electron Lasers
- Metallurgy and Material Science
- Magnetic properties of thin films
- Digital Rights Management and Security
- X-ray Spectroscopy and Fluorescence Analysis
- Nuclear Physics and Applications
- Metal and Thin Film Mechanics
- Advanced Data Storage Technologies
- Rare-earth and actinide compounds
TRIUMF
2022-2024
University of Victoria
2022-2024
University of British Columbia
2023
Simon Fraser University
2023
In a recent Letter by Romanenko et al., 1 the authors used lowenergy muon spin rotation (LE-lSR) 2,3 to measure Meissner screening profile in cutouts from Nb superconducting radio frequency (SRF) cavities, systematically comparing how different surface treatments affect properties of elemental type-II superconductor.They reported "strong" modification character upon mild baking at 120 C for 48 h, 4 which was interpreted as depth-dependent carrier mean-free-path resulting "gradient vacancy...
We report depth-resolved measurements of the Meissner screening profile in several surface-treated Nb samples using low-energy muon spin rotation (LE-$\mu$SR). In these experiments, implanted positive muons, whose stopping depths below Nb's surface were adjusted between ~10 nm to ~150 nm, reveal field distribution inside superconducting element via their spin-precession (communicated through radioactive decay products). compare how is modified by different treatments commonly employed...
A new high field spectrometer has been built to extend the capabilities of $\beta$-detected nuclear magnetic resonance ($\beta$-NMR) facility at TRIUMF. This beamline extension allows $\beta$-NMR spectroscopy be performed with fields up 200 mT parallel a sample's surface (perpendicular ion beam), allowing depth-resolved studies local electromagnetic spin polarized probes much higher applied than previously available in this configuration. The primary motivation and application is allow...
Abstract We report measurements of the first-flux-penetration field in surface-treated and coated Nb samples using <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mi>μ</mml:mi> <mml:mtext>SR</mml:mtext> stretchy="false">)</mml:mo> </mml:mrow> </mml:math> . Using thin Ag foils as energy moderators for implanted muon spin-probes, we ‘profile’ vortex penetration <mml:msub> <mml:mn>0</mml:mn> </mml:msub>...
Abstract Superconducting radio frequency (SRF) cavities, which are critical components in many particle accelerators, need to be operated the Meissner state avoid strong dissipation from magnetic vortices. For a defect-free superconductor, maximum attainable field for operation is set by superheating field, <?CDATA $B_{\mathrm{sh}}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mi>B</mml:mi> <mml:mrow> <mml:mi mathvariant="normal">s</mml:mi>...
We report measurements of the Meissner screening profile in a Nb(300 nm)/Al2O3 thin film using 8Liβ-detected nuclear magnetic resonance (β-NMR). The NMR probe 8Li was ion-implanted into Nb at energies ≤ 20 keV, corresponding to mean stopping depths comparable Nb’s penetration depth λ. 8Li’s strong dipole–dipole coupling with host 93Nb nuclei provided “cross-relaxation” channel that dominated low fields, which conferred indirect sensitivity local field via spin-lattice relaxation (SLR) rate...
<title>Abstract</title> We report direct measurements of the magnetic field screening at limits Meissner phase for two superconducting Nb samples. The samples are processed with different surface treatments that have been developed radio-frequency cavity applications — a “baseline” treatment and an oxygen-doping (“O-doping” ) treatment. show: 1) length is significantly longer in “O-doping” sample compared to sample; 2) near increases applied field; 3) evolution profile as material...
We report direct measurements of the magnetic field screening at limits Meissner phase for two superconducting Nb samples. The samples are processed with different surface treatments that have been developed radio-frequency cavity applications -- a "baseline" treatment and an oxygen-doping ("O-doping") treatment. show: 1) length is significantly longer in "O-doping" sample compared to sample; 2) near increases applied field; 3) evolution profile as material transitions from mixed phase; 4)...
We report measurements of the Meissner screening profile in a Nb(300 nm)/Al$_{2}$O$_{3}$ thin film using $^{8}$Li $β$-detected nuclear magnetic resonance ($β$-NMR). The NMR probe was ion-implanted into Nb at energies $\leq$ 20 keV, corresponding to mean stopping depths comparable Nb's penetration depth $λ$. $^{8}$Li's strong dipole-dipole coupling with host $^{93}$Nb nuclei provided "cross-relaxation" channel that dominated low fields, which conferred indirect sensitivity local field via...