56386309
SINGLE PARTICLE BEAM DYNAMICS DESIGN OF BSNS/RCS.
Rapid Cycling Synchrotron (RCS) is a key component of Beijing Spallation Neutron Source (BSNS). It accumulates and accelerates protons to design energy of 1.6 GeV, and extracts high energy beam to the target. As a high beam density and high beam power machine, low beam loss is also a basic requirement. An optimal lattice design is essential for the cost and the future operation. The lattice design of BSNS is presented, and the related dynamics issues are discussed. The injection/extraction scheme and the beam collimation system design are introduced.
209441918
BRIEF OVERVIEW OF PARTICLE ACCELERATORS IN CHINA
A brief overview of the main particle accelerators in China is given. New projects in the near future are also simply described.
121358236
Emittance balancing technique for the resonant slow extraction from a synchrotron
A new method is proposed to produce identical beam emittances in the transverse phase planes from a severely asymmetric beam extracted from a slow-cycling synchrotron. This is important to obtain a good beam distribution at the irradiation spot when the spot scanning method is used for the treatment in hadron therapy. The method makes use of the beam rotation effect either by a solenoid or by a rotational quadrupole section, referred to as rotator, to produce identical emittances in the two transverse phase planes. It is also helpful for the stabilization of the beam spot at the irradiation point. Simulation studies with an artificially generated beam have been carried out to prove the principle. The method is not only applicable to fixed treatment nozzles but also to rotational gantry nozzles. Both a solenoid and a section of quadrupole rotator can be used, with the former being ideal for proton gantries and the latter for fixed carbon nozzles. There is a practical limit in using room-temperature solenoid due to the high beam rigidity in the case of a carbon beam, for which a superconducting solenoid has to be used. The comparison with other methods and the practical applications of the method are also presented.
123202707
Chromaticity in Strong Focusing Accelerators and Storage Rings
The chromaticity formulae with accuracy to the first-order in momentum deviation in strong focusing accelerators & storage rings have been derived. It has been found that the edge magnetic field effects must be taken into account, otherwise the resultant errors introduced will be appreciable which increase rapidly with the decrease in machine size. They can not be neglected especially for proton and antiproton accumulators due to the very large momentum spread of the beams accumulated in them.
39781210
Fringe Field Interference Research on Quadrupole-Sextupole Assembly in BEPC-II
Many compact accelerators are increasingly popular nowadays. The studies on fringe field interference effect between adjacent magnets are becoming more important. Based on the 3-D multipole expansion technique, the integrated gradient deviation in a quadrupole magnet due to the appearance of neighboring sextupole is investigated. The quad-sext interference effect had been evaluated for BEPC-II. The relative impacts on accelerator tune shift will be obtained further and confirmed by experiments finally.
124386868
The Application of Adiabatic Theorem to the Beam Dynamics in Accelerators
In this paper, the adiabatic criterion and the formulae for calculating the increment of adiabatic invariant due to the nonadiabatic change of paramters in Hamiltonian are derived and we have found that this increment is quite small, even in the case where the Landau's adiabatic criterion[1] is violated.
124798718
Recent results from BESIII
125315096
eta(c) physics at BES III
An introduction for eta(c) physics research is presented in this paper, which shows that the mechanism of eta(c) decays can't be. well described by current theoretical models and detailed experimental measurements need to be done with larger eta(c) sample. Based on the expected J/psi and psi' events taken with the planed BES III detector in one year, the eta(c) physics researches are discussed extensively, including the measurements of branching fractions of different final states, the search for new decay, modes, precision measurements of mass and width, and the search for rare decays. At last, the study of eta'(c) decays is also discussed briefly.
112023627
Charm Fragmentation Function and Charm Fragmentation Fractions at ZEUS
123432115
Progress in light hadron spectroscopy at BESIII
Based on the 225 million J / ψ events and 106 million ψ ′ events taken at the BESIII detector, the recent results on light hadron spectroscopy are presented, including the partial wave analysis of J / ψ → γ p p ¯ and ψ ′ → p p ¯ η , confirmation of X(1835) and observation of two new resonances in J / ψ → γ π + π − η ′ , observation of a new resonance X(1870) in J / ψ → ω π + π − η and the first observation of isospin-violating decay mode of η ( 1405 ) → f 0 ( 980 ) π 0 .
11750018
Measurement of the charm fragmentation into D* mesons at HERA
The charm fragmentation function has been measured with the H1 and ZEUS detectors at HERA in the deep inelastic scattering and photoproduction regimes. The measured function has been compared to different fragmentation models implemented in leading-logarithm Monte Carlo simulations and next-to-leading-order calculations.