The ponderomotive potential structure of a multimode combined intense laser beam is studied. Using a three-dimensional test particle simulation, the interaction of slow electrons with the combined laser beam in vacuum is investigated. The calculation shows that electrons distributed on a large scale can be accelerated to relativistic energy in vacuum. A violent longitudinal bunch compression phenomenon is also presented and discussed.

Some latest developments of accelerator applications in China are given in this paper. The application areas mentioned here are including radiotherapy, radioactive isotope medicines, irradiation, non-destructive-test and cargo inspections. There are more than 700 linacs used for radiotherapy in china, and among them about 400 sets are made domestically. Specially emphasized are the cargo inspections applications of linacs in china. Until now, more than 50 large container inspection systems domestically produced using linacs as x-ray sources have been installed in China and other countries. Cyclotrons are also developed for medicine producing and high voltage accelerators with high beam power for removing SO2 and NOx from coal-fired flue gas in electricity plant. This paper is mainly on the accelerator technology and application activities in China carried out these years.

The results of wakefield calculations for a collection of beamline elements in the TTF Injector II are presented. These elements include crosses, bellows, and steps in the beamline, valves and the bunch compressor. Methods to reduce the wakefield effects due to these elements are also investigated.

A multi-cell thermionic RF electron gun with significantly reduced back bombardment effect is designed, built, and its performance measured. A macro-pulse current of about 800mA, maximum electron energy of 1.8MeV and geometric RMS emittance after the alpha magnet of 20-30 πmmmrad are obtained. This RF electron gun will be used in the Beijing free electron laser facility (BFEL).

采用模拟计算电子——光子耦合输运的蒙特卡罗程序EGS4 来模拟计算半价层测量能量方法的过程。得到的半价层数值在一定范围内与Varian公司给出的建议数据和实际测量数据基本吻合。分析了半价层测量的各种影响因素,同时给出了测量能量时应注意的事项,并为实际应用提供了参考数据。