A5048076528- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Advanced NMR Techniques and Applications
- Atomic and Subatomic Physics Research
- Quantum, superfluid, helium dynamics
- Gyrotron and Vacuum Electronics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Electron Spin Resonance Studies
- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Nuclear physics research studies
- Thin-Film Transistor Technologies
- Organic Electronics and Photovoltaics
- Crystallography and Radiation Phenomena
- Theoretical and Computational Physics
- Conducting polymers and applications
- Physics of Superconductivity and Magnetism
- Iron and Steelmaking Processes
- Magnetic confinement fusion research
- Magneto-Optical Properties and Applications
- Quantum and electron transport phenomena
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Chemical Looping and Thermochemical Processes
- Earthquake Detection and Analysis
Hong Kong Baptist University
2023-2024
University of Michigan–Ann Arbor
2002-2017
Indiana University Bloomington
2001-2009
Thomas Jefferson National Accelerator Facility
2009
University of Bonn
2009
Cornell University
2004-2009
Forschungszentrum Jülich
2009
University of Groningen
2009
Japan Proton Accelerator Research Complex
2009
United States Naval Research Laboratory
2007
Abstract The reproducibility issue is impeding the progress of commercialization in organic photovoltaic (OPV) devices, as difficulty precise micro‐nano structure control bulk heterojunction films, well ineluctable fluctuations molecular weight and polydispersity index synthetic process. Due to such intrinsic properties, poor regioregularity significantly affects batch‐to‐batch variation performance large‐area or integrative scattered OPV devices. Seeking alternatives compensatory strategies...
In June 2006 an early opportunity arose to compare occultation‐based electron density profiles with incoherent scatter radar data. The former were made available by the constellation of satellites called COSMIC. We find that value peak plasma in F region is reasonably well characterized but altitude overestimated above about 300 km and underestimated below height. A simple Abel transform not suitable for determining E profiles, even daytime. also compared emission strength recorded Tiny...
We recently studied the spin flipping of a vertically polarized, stored 139-MeV proton beam. To flip spin, we induced an rf depolarizing resonance by sweeping our solenoid magnet's frequency through frequency. With multiple flips, found polarization loss 0.0000 \ifmmode\pm\else\textpm\fi{} 0.0005 per under best conditions; this increased significantly for small changes in conditions. Minimizing depolarization during each is especially important because frequent could reduce systematic errors...
We measured the analyzing power A out to ${\mathit{P}}_{\mathrm{\ensuremath{\perp}}}^{2}$=7.1 (GeV/c${)}^{2}$ with high precision by scattering a 24-GeV/c unpolarized proton beam from new University of Michigan polarized target; target's 1-W cooling allowed intensity more than 2\ifmmode\times\else\texttimes\fi{}${10}^{11}$ protons per pulse. This together unexpectedly average target polarization about 85% unusually accurate measurements at large...
A recent experiment studied the effect of an rf solenoid magnet and a partial Siberian snake on 120-MeV polarized proton beam. We measured frequencies ``rf-induced''depolarizing resonance for different values strength; this frequency measurement determined spin tune ${\ensuremath{\nu}}_{\mathrm{sp}}$, which is number processions in one turn around ring. 4% increased rf-induced depolarizing by predicted 11 kHz thus shifted \ensuremath{\Delta}${\ensuremath{\nu}}_{\mathrm{sp}}$=0.006...
We have demonstrated for the first time spin flipping of a polarized proton beam stored in ring containing nearly $100%$ Siberian snake; we did this using ``snake'' depolarizing resonance induced by an rf solenoid magnet. By varying solenoid's ramp time, frequency range, and voltage, reached spin-flip efficiency about $91%$. This was probably reduced because horizontal stable direction not perpendicular to longitudinal field solenoid, possibly nearby synchrotron sideband resonances. The...
The morphological analysis of bulk heterojunction (BHJ) active layer stands as a critical imperative for advancing the performance future organic solar cells. Conventional characterization tools employed investigation often require substantial resources, both in cost and physical space, thereby imposing restraints on research endeavors this domain. Here, we extend application charge carrier transport beyond conventional mobility assessments, utilizing it table-top method preliminary...
Stored beams of polarized protons, electrons, or deuterons can be spin flipped by sweeping an rf dipole's solenoid's frequency through resonance. Fitting such data to the modified Froissart-Stora equation's resonance strength ${\mathcal{E}}_{\mathrm{FS}}$ gave very large deviations from $^{*}\mathcal{E}_{Bdl}$ obtained each magnet's $\ensuremath{\int}{B}_{rms}dl$. We recently varied sweep range $\ensuremath{\Delta}f$, and momentum spread $\ensuremath{\Delta}p/p$ betatron tune...
We recently accelerated a polarized proton beam from 95 to 380 MeV through both the $G\ensuremath{\gamma}=2$ imperfection depolarizing resonance and $G\ensuremath{\gamma}=7\ensuremath{-}{\ensuremath{\nu}}_{y}$ intrinsic resonance. The flipped spin, while initially caused partial depolarization. then pulsed vertical kicker magnet for about 500 ns increase beam's betatron amplitude; this made much stronger. By varying strength start time of kicker, we observed sharp spin flip due now very strong
The behavior of ``overlapping'' depolarizing resonances was studied using a stored 106.4-MeV polarized proton beam. We used an rf solenoid magnet to create ``rf induced'' resonance which then forced overlap with the G\ensuremath{\gamma}=2 imperfection resonance. found significant interactions between two by varying their frequencies and strengths; frequency strongly affected response correction magnetic fields. Siberian snake overcame all observable depolarization due overlapping maintained...
We recently studied spin flipping of a 270 MeV vertically polarized deuteron beam stored in the Indiana University Cyclotron Facility Cooler Ring. adiabatically swept an rf solenoid's frequency through rf-induced resonance and observed its effect on deuterons' vector tensor polarizations. After optimizing crossing rate maximizing voltage, we measured spin-flip efficiency 94.2%+/-0.3%. also found striking behavior spin-1 polarization.
We recently analyzed all available data on spin-flipping stored beams of polarized protons, electrons, and deuterons. Fitting the modified Froissart-Stora equation to measured polarization after crossing an rf-induced spin resonance, we found 10--20-fold deviations from depolarizing resonance strength equations used for many years. The was typically manipulated by linearly sweeping frequency rf dipole or solenoid through resonance; spin-flip efficiencies up $99.9%$ were obtained. Lorentz...
A recent experiment in the IUCF cooler ring studied adiabatic turn-on of a partial Siberian snake at 370 MeV, where spin tune, ${\ensuremath{\nu}}_{\mathit{s}}$ is 21/2 for all strengths. The consisted two rampable warm solenoid magnets series with superconducting solenoid; this combination allowed varying strength between about 0 and 25% MeV. We measured beam polaraization after either 1, 2, or 10 times; we found good precision that no polarization was lost. This supports conjecture can be...
We recently studied the first acceleration of a spin-polarized beam through depolarizing resonance using partial Siberian snake. accelerated polarized protons from 95 to 140 MeV while ramping 10% snake along with cycle. The suppressed all observable depolarization due $G\ensuremath{\gamma}=2$ imperfection which occurred near 108 during acceleration. However, 20% and 30% snakes apparently moved $G\ensuremath{\gamma}=7\ensuremath{-}{\ensuremath{\nu}}_{y}$ intrinsic 177 into our energy range;...
We recently studied the spin-flipping efficiency of an rf-dipole magnet using a 120-MeV horizontally polarized proton beam stored in Indiana University Cyclotron Facility Cooler Ring, which contained nearly full Siberian snake. flipped spin by ramping rf dipole's frequency through rf-induced depolarizing resonance. By adiabatically turning on dipole, we minimized loss. After optimizing ramp parameters, used 100 multiple flips to measure spin-flip 99.63+/-0.05%. This result indicates that...
We recently used a new ferrite rf dipole to study spin flipping of $2.1\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}/c$ vertically polarized proton beam stored in the COSY Cooler Synchrotron J\"ulich, Germany. swept dipole's frequency through an rf-induced resonance flip beam's polarization direction. After determining resonance's frequency, we varied range, ramp time, and number flips. At maximum strength optimum range measured spin-flip efficiency $99.92\ifmmode\pm\else\textpm\fi{}0.04%$....
Using a 104 MeV stored polarized proton beam and full Siberian snake, we recently found evidence for so-called ``snake'' depolarizing resonance. A snake forces the spin tune ${\ensuremath{\nu}}_{s}$ to be half integer. Thus, if vertical betatron ${\ensuremath{\nu}}_{y}$ is set near quarter integer, then ${\ensuremath{\nu}}_{s}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}n\ifmmode\pm\else\textpm\fi{}2{\ensuremath{\nu}}_{y}$ second-order resonance can depolarize beam. Indeed, with deep...
A recent experiment using a 160 MeV stored spin-polarized proton beam found clear evidence for second-order intrinsic depolarizing resonance. With 20% partial Siberian snake, we studied first-order resonance; then discovered and the resonance by changing both horizontal vertical betatron tunes. As expected, this is much weaker than it probably due to sextupole fields plus coupling between oscillations caused snake.
We recently used an rf dipole magnet to study the spin flipping of a 120 MeV horizontally polarized proton beam stored in presence nearly full Siberian snake Indiana University Cyclotron Facility Cooler Ring. flipped by ramping dipole's frequency through rf-induced depolarizing resonance. After optimizing ramp parameters, we multiple flips measure spin-flip efficiency $86.5\ifmmode\pm\else\textpm\fi{}0.5%$. The was apparently limited field strength dipole. This result indicates that should...
We recently studied spin flipping of a $1.94\text{ }\text{ }\mathrm{GeV}/c$ vertically polarized proton beam at COSY in J\"ulich, Germany. swept an rf-dipole's frequency through rf-induced resonance to flip the beam's polarization direction. After determining resonance's frequency, we varied dipole's strength, range, and ramp time. At maximum optimum range time, measured spin-flip efficiency $99.3%\ifmmode\pm\else\textpm\fi{}0.1%$. This result indicates that rf dipole may allow efficient...
We recently studied the spin manipulation of $1.85\text{ }\text{ }\mathrm{GeV}/c$ vertically polarized deuterons stored in COSY cooler synchrotron. adiabatically swept an rf dipole's frequency through rf-induced resonance and observed its effect on deuterons' vector tensor polarizations. After optimizing crossing rate maximizing voltage, we measured spin-flip efficiencies $97\ifmmode\pm\else\textpm\fi{}1%$ $98.5\ifmmode\pm\else\textpm\fi{}0.3%$ two separate runs. also confirmed at higher...
We recently forced a 140 MeV polarized proton beam to cross intrinsic depolarizing resonances by varying partial Siberian snake's strength for different values of the vertical and horizontal betatron tunes ${\ensuremath{\nu}}_{y}$ ${\ensuremath{\nu}}_{x}$. A weak second-order resonance was observed in ${\ensuremath{\nu}}_{x}$ sweep; moreover, an unexpected spin flip found sweep. also varied snake ramp time identify regions where crossings occurred during variation; these polarization...