A5101486369- Particle accelerators and beam dynamics
- Plasma Diagnostics and Applications
- Particle Accelerators and Free-Electron Lasers
- Magnetic confinement fusion research
- Nuclear Physics and Applications
- Pulsed Power Technology Applications
- Electrostatic Discharge in Electronics
- Gyrotron and Vacuum Electronics Research
- Vacuum and Plasma Arcs
- Superconducting Materials and Applications
- Solidification and crystal growth phenomena
- Gas Dynamics and Kinetic Theory
- Integrated Circuits and Semiconductor Failure Analysis
- Diamond and Carbon-based Materials Research
- Analytical Chemistry and Sensors
- Nanopore and Nanochannel Transport Studies
- Muon and positron interactions and applications
- nanoparticles nucleation surface interactions
- Quantum and electron transport phenomena
- Gamma-ray bursts and supernovae
- Graphene research and applications
- Power Transformer Diagnostics and Insulation
Peking University
1985-2024
East China Normal University
2024
State Key Laboratory of Nuclear Physics and Technology
2008-2016
Key Laboratory of Nuclear Radiation and Nuclear Energy Technology
2010-2013
Low-dimensional water transport can be drastically enhanced under atomic-scale confinement. However, its microscopic origin is still debate. In this work, we directly imaged the atomic structure and of two-dimensional islands on graphene hexagonal boron nitride surfaces using qPlus-based force microscopy. The lattice island was incommensurate with surface but commensurate owing to different electrostatics. area-normalized static friction diminished as area increased by a power ~-0.58,...
An electron cyclotron resonance (ECR) ion source is designed for the production of high-current beams various gaseous elements. At Peking University (PKU), primary study focused on developing suitable permanent magnet ECR sources (PMECRs) separated function radio frequency quadrupole (SFRFQ) accelerator and Neutron Imaging Facility. Recently, other kinds high-intensity are required new acceleration structure demonstration, simulation fusion reactor material irradiation, aviation bearing...
A permanent magnet electron cyclotron resonance ion source PMECR II is used to generate proton ions for radio frequency quadrupole (RFQ) injection at Peking University (PKU). The fractions of the extracted beam were measured positions both after extraction system and end low energy transport line (LEBT). Experiments show that fraction has a rise time within pulse, its value varies with pulse width microwave power. different are comparable.
A deuteron radio frequency quadrupoles injector h has been developed at Peking University. permanent magnetic electron cyclotron resonance (ECR) ion source is used in the system. 50 keV 100 mA proton beam extracted from ECR and measured normalized rms emittance 0.11–0.14π mm mrad. also kV with 83 total current its less than 0.18π The transmission investigated on a low energy transport test bench, up to 93% can be reached. new two solenoids designed being constructed. All development results...
The deuteron injector developed for the PKUNIFTY (Peking University Neutron Imaging Facility) has been installed and commissioned at Peking (PKU). system must transfer 50 keV mA of D+ ion beam to entrance 2 MeV radio frequency quadrupole (RFQ) with 10% duty factor (1 ms, 100 Hz). A compact 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) source a 1.36 m long low energy transport (LEBT) line using two solenoids was as injector. ϕ5 mm four-quadrant diaphragm used simulate RFQ...
In an electron cyclotron resonance (ECR) ion source, the magnetic field along axis of plasma chamber and extraction system is a key parameter. At Peking University, new 2.45 GHz ECR source (PMECR III), dedicated to proton production, has been developed investigate influence on gas discharge beam characteristics. The configuration provided by two permanent magnet rings independently tunable axis. Moreover, position changes moving whole using different lengths electrode. A brief description...
A set of new ion extraction electrodes have been designed for the permanent magnetic electron cyclotron resonance source at Peking University to improve beam quality and transmission. PBGUNS has used optimize simulate behavior region. The experiments showed that with system, half divergence angle can be less than 40 mrad normalized rms emittance is about 0.13π mm when extracted current 100 mA 50 keV in pulse mode. voltage suppression electrode great effect on divergence. microwave power gas...
To meet the requirements of developing separated function radio frequency quadruple (rfq) and upgrading 1 MeV integral split ring rfq accelerator, an electron cyclotron resonance O(+) ion source low energy beam transport (LEBT) system have been developed. Using two Einzel lenses to focus beam, more than 6 mA peak current with 22 keV can be easily obtained at end LEBT when duty faction is 1/6. The normalized root-mean-square emittance 90% about 0.12pi mm mrad. By changing focusing power...
An experimental method is related to research the space charge compensation (SCC) effect in low energy intense proton beams by analyzing residual gas (RG) ion signals. The signal curves were measured with an spectrometer under RG pressure from 1.2x10(-3) 1.6x10(-2) Pa. Most of data showed a similar trend our theoretical predicts. From spectra potential distribution beam was calculated both and without SCC effect. Moreover, as preliminary result, best compensating point achieved for transport...
PKUNIFTY (PeKing University Neutron Imaging FaciliTY), a thermal neutron imaging facility based on 2 MeV RFQ accelerator, has been constructed at Peking University. Its deuteron injector, which consists of 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) ion source and two-solenoid low energy beam transport (LEBT), aims producing delivering 50 mA, keV with duty factor 10% (1 ms, 100 Hz). In the preliminary tests ECR LEBT are required to operate various factors (from 1% 10%)....
As a new device, plasma window has been designed to use discharge separate atmosphere from vacuum with high difference of pressure. It many excellent properties, being able be used as available passage for ion beam negligible energy loss, also impervious radiation damage and thermal damage. Normally focusing by accelerators is not that easy achieve within channel small cross section. 10 mm diameter window's experimental realization could contribute its further application in accelerator...
The microscopic stress field inhomogeneity in the interfacial region adjacent to liquid surface is fundamental origin of tension, but because broadening due capillary fluctuations, a detailed molecular level understanding remains elusive. In this work, we deconvolute fluctuations reveal intrinsic and show that atomic-level contributions tension are similar functional form across variety monatomic systems. These confined an approximately 1.5±0.1 times particle diameter for all systems...
The present work describes the principle, structure and experimental results of a side extraction PIG ion source with permanent magnetic mirror type field. is light handy low power consumption high ionization efficiency. In experiments using BF3, N2 Ar, total beam current 1-2 ma can be obtained 50-150 watt arc power. relative yields 11B+, 14N+, 40Ar2+, 11B2+ 14N2+ are 50-60%, 70-80%, 20-30%, 5% 7% that beam, respectively. 11B3+, 14N5+ 40Ar6+ also measurable. addition, multicathode has been...