A5019912558- Particle physics theoretical and experimental studies
- Particle accelerators and beam dynamics
- High-Energy Particle Collisions Research
- Particle Accelerators and Free-Electron Lasers
- Particle Detector Development and Performance
- Superconducting Materials and Applications
- Quantum Chromodynamics and Particle Interactions
- Muon and positron interactions and applications
- Gyrotron and Vacuum Electronics Research
- Neutrino Physics Research
- Geomagnetism and Paleomagnetism Studies
- Cosmology and Gravitation Theories
- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Characterization and Applications of Magnetic Nanoparticles
- Magnetic confinement fusion research
- Iron oxide chemistry and applications
- Vacuum and Plasma Arcs
- Plasma Diagnostics and Applications
- Advanced Materials Characterization Techniques
- Electronic and Structural Properties of Oxides
- Surface and Thin Film Phenomena
- Scientific Research and Discoveries
- Computational Physics and Python Applications
- Magnetic properties of thin films
Ministry of Industry and Information Technology
2024
Beihang University
2024
University of Pittsburgh
2015
Aix-Marseille Université
2010-2012
Max Planck Institute for Physics
2011-2012
Institut National de Physique Nucléaire et de Physique des Particules
2006-2012
Centre National de la Recherche Scientifique
2006-2012
European Organization for Nuclear Research
2012
Michigan State University
2011
Fermi National Accelerator Laboratory
1983-2008
Radio frequency (RF) control is a key technique in cold atom experiments. Here, we present new design based on virtual load, where low-frequency coil with of up to 30\,MHz, functions as both an inductor and power-sharing element capacitive transformer circuit. This enables highly efficient RF circuit tunable matching bandwidth. It integrates broadband narrowband coils into compact configuration, overcoming the distance limitations metallic chambers. The system, tested 10-second evaporative...
We present measurements of dark currents and x rays in a six cell 805 MHz cavity, taken as part an rf development program for muon cooling, which requires high power, stored energy, low frequency cavities operating strong magnetic field. have done the first systematic study behavior power (2.5--4 T) Our extend over very large dynamic range current provide good fits to Fowler-Nordheim field emission model assuming mechanical structures produce enhancements at surface. The locally enhanced...
We have measured the effects of high (0--4.5 T) magnetic fields on operating conditions 805 MHz accelerating cavities, and discovered that maximum gradient drops as a function axial field. While any cavity is governed by number factors including conditioning, surface topology materials, we argue $\mathbf{J}\ifmmode\times\else\texttimes\fi{}\mathbf{B}$ forces within emitters are mechanism for enhanced breakdown in fields. The pattern changes over time show an example bright emitter which...
We describe a model of damage in rf cavities and show how this can limit cavity operation. first present review mechanisms that may or not affect the ultimate fields be obtained cavities, assuming mechanical stress explains triggers breakdown events. method quantifying surface caused by events terms spectrum field enhancement factors, $\ensuremath{\beta}$, for asperities on surface. then an equilibrium develop between conditioning effects, determine performance experimental evidence...
We evaluate the ${e}^{\ensuremath{-}}{e}^{+}\ensuremath{\rightarrow}{e}^{\ensuremath{-}}{e}^{+}+h$ process through $ZZ$ fusion channel at International Linear Collider operating 500 GeV and 1 TeV center-of-mass energies. perform realistic simulations on signal background processes. With judicious kinematic cuts, we find that inclusive cross section can be measured to 2.9% after combining $500\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ $1\text{ }{\text{ab}}^{\ensuremath{-}1}$ runs. A...
Antiprotons for the Fermilab pp collding beam project (Tevatron I) will be extracted from an 8 GeV accumulation ring in a few (1 to 3) bunches of ~ 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> , single bunch at time. To preserve stack as source subsequent bunches, each removed dense core with isolated bucket harmonic number h = 2. The longitudinal emittance range 1.5 eVs, roughly five times what Main Ring usually accelerates...
The MuCool Experiment has been continuing to take data with 805 and 201 MHz cavities in the Test Area. system uses RF power sources from Fermilab Linac. Although experimental program is primarily aimed at Muon Ionization Cooling (MICE), we have studying dependence of limits on frequency, cavity material, high magnetic fields, gas pressure, coatings, etc. general aim understanding basic mechanisms involved. cavity, essentially a prototype for MICE, was made using cleaning techniques similar...
The inductance of the vacuum chamber Proton Storage Ring at Los Alamos National Laboratory was intentionally increased by introduction ferrite rings to counteract longitudinal space-charge effect intense beam. magnetic permeability could be adjusted introducing current into solenoids wound around ferrite. Results show that minimum rf voltage necessary stabilize beam against $e\ensuremath{-}p$ instability may reduced over previously measured. injected bunch length observed longer when heavily...
A muon cooling channel calls for very high accelerating gradient RF structures to restore the energy lost by muons in absorbers. The have be operated a strong magnetic field and thus use of superconducting cavities is excluded. To achieve shunt impedance while maintaining large enough aperture accommodate transverse emittance beam, cavity design adopted pillbox-like geometry with thin Be foils terminate electromagnetic at iris. possibility using grids thin-walled metallic tubes termination...
Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation D. Li, M. Dickson, S. Virostek, Zisman, A. Bross, Moretti, Z. Qian, J. Norem, R. Rimmer, Huang, Y. Torun, Summers, W. Lau, Yang; MUCOOL/MICE RF Cavity R&D Programs. AIP Conf. Proc. 21 February 2008; 981 (1): 299–302. https://doi.org/10.1063/1.2898967 Download citation file: Ris (Zotero) Reference Manager...
The proton driver for the muon collider must produce short pulses of protons in order to facilitate cooling and operation with polarized beams. In test methods producing these bunches, we have operated alternating-gradient synchrotron near transition studied procedures which involved moving energy ${\ensuremath{\gamma}}_{t}$ beam energy. We were able stable bunches $3--5\ifmmode\times\else\texttimes\fi{}{10}^{12}$ rms widths $\ensuremath{\sigma}=2.0--2.7\mathrm{ns}$ longitudinal bunch areas...
The rf R&D program for high gradient, low frequency cavities to be used in muon cooling systems is underway the Fermilab MUCOOL Test Area. Cavities at 805 and 201 MHz are tests of conditioning techniques, surface modification breakdown studies. This work has Muon Ionization Cooling Experiment (MICE) as its immediate goal efficient neutrino sources colliders long term goal. We study breakdown, dark current production under a variety conditions.
Magnetic particle imaging (MPI) is an emerging molecular technique that relies on the nonlinear magnetization response of superparamagnetic iron oxide nanoparticles. Open-sided MPI (OS-MPI) has attracted considerable interest for its potential to enhance interventional procedures. However, improving spatial resolution OS-MPI poses a significant challenge, mainly due inefficiencies selection coils in generating, rotating, and shifting high-gradient field-free line (FFL). To address this...
Open-sided magnetic particle imaging (OS-MPI) has garnered significant interest due to its potential for interventional applications. However, the system matrix calibration in OS-MPI using sequential scans is a time-consuming task and susceptible low signal-to-noise ratio (SNR) resulting from small sample size. These challenges have hindered practical implementation of matrix-based reconstruction sequentially scanned OS-MPI. To address these issues, we propose novel method, named scan-based...
ATLAS is one of the four major Large Hadron Collider (LHC) experiments that will start data taking in 2007. It designed to cover a wide range physics topics. The trigger system has be able reduce an initial 40 MHz event rate, corresponding average 23 proton-proton inelastic interactions per every 25 ns bunch crossing, 200 Hz admissible by Data Acquisition System. divided three different levels. first provides signal describing signature using dedicated custom hardware. This must confirmed...
A multi-laboratory collaboration is studying the feasibility of building a muon collider, first phase which maybe neutrino factory. The space occupied by muons very large and needs to be cooled several orders magnitude for either machine, 100,000 1 million collider ten 100 Ionization cooling base line method cooling. This scheme uses hydrogen absorbers rf re-acceleration in long series magnetic focusing channels cool muons. At Fermilab two cavity types are under study provide required...
There is a new magnetic alloy called Finemet which has very constant /spl mu/'/sub p/Qf up to sim/2 kG and stable at high flux density temperature. It may be good candidate for high-gradient RF cavities. However, it rather low quality factor therefore lossy. We compare the pros cons of versus common ferrite, when used in low-energy accelerating cavities, insertion space-charge compensation, barrier
A 7.5 MHz RF cavity and power amplifier have been built tested at Fermilab as part of the proton Driver Design Study. The project goal was to achieve highest possible accelerating gradient 15 Hz with a 50% duty cycle. To reduce beam loading effects, low shunt impedance (500/spl Omega/) design chosen. 46cm long single gap uses 5 inductive cores, consisting nanocrystalline soft magnetic alloy Finemet, peak voltage kV. 95cm OD tape wound cores cut in half increase Q are cooled from both sides...