The BEPCⅡ injector linac upgrade goal aims at higher beam energy with smaller beam emittance and energy spread to meet the colliding luminosity upgrade by two orders of magnitude.This paper describes the beam commiss...The BEPCⅡ injector linac upgrade goal aims at higher beam energy with smaller beam emittance and energy spread to meet the colliding luminosity upgrade by two orders of magnitude.This paper describes the beam commissioning and operation.The beam energy,energy spread,current,transmission and emittance have met the design goal.The beam orbit and energy instabilities have been studied and a steady beam operation has been realized.展开更多
Further studies on beam emittance measurement have been made to improve the emittance measurement precision at BEPCⅡ linac.Some problems in the measurement are solved and a code for beam emittance calculation is deve...Further studies on beam emittance measurement have been made to improve the emittance measurement precision at BEPCⅡ linac.Some problems in the measurement are solved and a code for beam emittance calculation is developed.With these improvements,the emittance measurement precision was upgraded.展开更多
Purpose The research focuses on the related measurement and shielding works for solving the spatial electromagnetic radiation and interference problems of the BEPCⅡLinac.Methods The radiation frequency and intensity ...Purpose The research focuses on the related measurement and shielding works for solving the spatial electromagnetic radiation and interference problems of the BEPCⅡLinac.Methods The radiation frequency and intensity can be determined by using a set of antennas connected with a spectrum analyser.Results The source of the radiation is located on the cable connectors of some device panels.The radiation intensity is significantly reduced after wrapping the connectors with the radiation shielding tape.Conclusions The entire research process includes the selection of a domestically made ultra-wideband antenna,the proposal of the measurement methods,the locating of the radiation source,the performance measurement of the radiation shielding tape and the shielding of the radiation.It provides a whole set of feasible solutions for similar problems in accelerators.展开更多
An RF pulse compressor is a device used to convert a long RF pulse to a short one with a much higher peak RF magnitude. SLED can be regarded as the earliest RF pulse compressor to be used in large-scale linear acceler...An RF pulse compressor is a device used to convert a long RF pulse to a short one with a much higher peak RF magnitude. SLED can be regarded as the earliest RF pulse compressor to be used in large-scale linear accelerators. It has been widely studied around the world and applied in the BEPC and BEPCⅡ linac for many years. During routine operation, error and jitter effects will deteriorate the performance of SLED, either on the output electromagnetic wave amplitude or phase. The error effects mainly include the frequency drift induced by cooling water temperature variation and the frequency/Q 0 /β unbalances between the two energy storage cavities caused by mechanical fabrication or microwave tuning. The jitter effects refer to the PSK switching phase and time jitters. In this paper, we re-derive the generalized formulae for the conventional SLED used in the BEPCⅡ linac, and the error and jitter effects on SLED performance are also investigated.展开更多
文摘The BEPCⅡ injector linac upgrade goal aims at higher beam energy with smaller beam emittance and energy spread to meet the colliding luminosity upgrade by two orders of magnitude.This paper describes the beam commissioning and operation.The beam energy,energy spread,current,transmission and emittance have met the design goal.The beam orbit and energy instabilities have been studied and a steady beam operation has been realized.
文摘Further studies on beam emittance measurement have been made to improve the emittance measurement precision at BEPCⅡ linac.Some problems in the measurement are solved and a code for beam emittance calculation is developed.With these improvements,the emittance measurement precision was upgraded.
基金Youth Innovation Promotion Association of the Chinese Academy of Sciences,2020015,Xiang He
文摘Purpose The research focuses on the related measurement and shielding works for solving the spatial electromagnetic radiation and interference problems of the BEPCⅡLinac.Methods The radiation frequency and intensity can be determined by using a set of antennas connected with a spectrum analyser.Results The source of the radiation is located on the cable connectors of some device panels.The radiation intensity is significantly reduced after wrapping the connectors with the radiation shielding tape.Conclusions The entire research process includes the selection of a domestically made ultra-wideband antenna,the proposal of the measurement methods,the locating of the radiation source,the performance measurement of the radiation shielding tape and the shielding of the radiation.It provides a whole set of feasible solutions for similar problems in accelerators.
基金Supported by the National Natural Science Foundation of China (11105164)
文摘An RF pulse compressor is a device used to convert a long RF pulse to a short one with a much higher peak RF magnitude. SLED can be regarded as the earliest RF pulse compressor to be used in large-scale linear accelerators. It has been widely studied around the world and applied in the BEPC and BEPCⅡ linac for many years. During routine operation, error and jitter effects will deteriorate the performance of SLED, either on the output electromagnetic wave amplitude or phase. The error effects mainly include the frequency drift induced by cooling water temperature variation and the frequency/Q 0 /β unbalances between the two energy storage cavities caused by mechanical fabrication or microwave tuning. The jitter effects refer to the PSK switching phase and time jitters. In this paper, we re-derive the generalized formulae for the conventional SLED used in the BEPCⅡ linac, and the error and jitter effects on SLED performance are also investigated.
