[en] For the Phase 2 of HLS (Hefei Light Source) Project, many sextupoles and octupoles have been installed in the machine to improve the operation condition. These nonlinear elements will introduce nonlinear effects to the beam dynamics. The authors apply Frequency Map Analysis to the HLS ring. By analyzing the resonance lines on the tune map, the authors find that the calculated lattice of GPLS mode lies on the weak chaotic zone, and the operating mode is better. (authors)

[en] Penetrating depth and dose distribution of electron beam in flue gas can influence efficiency of desulfurization and denitration. Beam energy loss during passing through the metal foil window has been calculated by theory and Monte Carlo simulation. Electron beam penetrating depth and dose distribution in the flue gas irradiation vessel have been obtained as well. Some conclusions have been gotten: the optimal electron beam energy is 700 keV. Cross sectional dimensions of the reaction chamber is selected about 1.0 m x 3.5 m. The work mode is face to face irradiation with two electron accelerators. (authors)

[en] Based on the principle of coupling impedance bench measurement, the validity of this method is discussed by simulation method. Beginning with the analysis of electro-magnetic field in homogeneous circular waveguide and coaxial transmission line, the physical concept and source of validity question of coaxial-wire method are described and a general conclusion is obtained. Then some results obtained by other methods are reviewed briefly. Finally, the simulation method to analyze the validity problem and the main results are presented. The simulation method can not only be applied to most accelerator components, but also give more precise and direct results

[en] Hefei synchrotron radiation Light Source (HLS) is a low energy Synchrotron Radiation (SR) facility. The SR produced from the HLS is in a series of pulses with a strict time structure. To meet some experiments which need long interval SR pulses, a new method, local vertical bump, was proposed. Physical calculations and numerical simulations have been done to demonstrate its feasibility

[en] In HLS (Hefei synchrotron Light Source), some experimental stations need SR pulse with long interval, which far exceeds HLS can provide now. In order to satisfy their needs, we proposed a scheme of using local vertical bump to lengthen the interval of SR pulses. We have designed a fast kicker magnet system, in which the pulse modulator is designed based on PFL technology and the kicker is an air-core kicker magnet. Preliminary measurements denote that the kicker system can meet the requirements of design

[en] The coaxial wire method is the standard method to measure longitudinal and transverse coupling impedance adopted in current accelerator laboratories, and the question about its validity is the focus by accelerator physicists. Differing from other references, in the paper the measurement process is numerically simulated and the effect of inner conductor design parameters including the radius of inners and distance between inners on measurement results is analysed. The simulation results show that the inner conductor design will effect the accuracy of measurement result of impedance, but the spectrum properties of impedance is reasonable

[en] In this paper the old longitudinal coupling impedance measurement system of National Synchrotron Radiation Laboratory is reviewed briefly. Considering the deficiency of the old system and advance of measurement apparatus, the improvements of measurement principle and hardwares were made. The measurement principle, system hardware configuration of new improved measurement system based on coaxial-wire method is presented in details. The measured impedance is agreement well with the calculated impedance by ABCI code, and the performance of the new system was demonstrated

[en] A 40kV/20kW switching-mode pulse forming network (PEN) charging power supply was developed by constant-current, series-resonant and soft-switching techniques. High pulse to pulse repeatability was achieved even under the condition of high repetition rate and small PFN capacitance. The power supply also featured in high efficiency, small size and the ability of being used in parallel mode. The techniques can be applied to injection/extraction system of circular accelerators, klystron modulators in Linacs and radar transmission. Design of the power supply and PFN charging and discharging experiments are presented in the paper

[en] A quasi-isochronous storage ring is designed by manipulating lattice parameters to introduce a negative dispersion function to the dispersion section. This quasi-isochronous storage ring is designed for a THz synchrotron radiation source. The simulation of the optics function and beam emittance shows its feasibility, and the tracing result of particles indicates that the designed ring has a good particle dynamic aperture. In addition, a three-dimensional model of the vacuum chamber used for photon radiation in the quasi-isochronous mode is also designed. The eigenmodes of the chamber are simulated, and characteristic parameters such as quality factor, power loss and characteristic impedance are also calculated. The result shows that the vacuum chamber has little effect on the circulating beam. (authors)

[en] Based on the beam loading theory in storage ring, traditional mode with large detuned angle and tuned mode of RF system in the injection process of Hefei Light Source (HLS) were calculated and disadvantages of these two modes were analyzed. Then a more flexible adjustment mode was put forward. In the injection process of HLS, beam would be injected and accumulated higher than design value 300 mA with appropriated parameters of new RF system. (authors)