For a long pulse free-electron laser(FEL)in the low gain regime,an approximate expression is given to describe the optical field gain from the small signal to the weak saturation.The result is shown to agree with thos...For a long pulse free-electron laser(FEL)in the low gain regime,an approximate expression is given to describe the optical field gain from the small signal to the weak saturation.The result is shown to agree with those from a 1-D computer simulation.展开更多
An S-band cavity BPM is designed for a new injector in National Synchrotron Radiation Laboratory. A re-entrant position cavity is tuned to the TM110 mode as position cavity. Cut-through waveguides are used as pickups ...An S-band cavity BPM is designed for a new injector in National Synchrotron Radiation Laboratory. A re-entrant position cavity is tuned to the TM110 mode as position cavity. Cut-through waveguides are used as pickups to suppress the monopole signal. Theoretical resolution of this design is 31 nm. A prototype cavity BPM system is manufactured for off-line cold tests. The wire scanning method is used to calibrate the BPM and estimate the performance of the on-line BPM system. A cross-talk problem has been detected during the cold test. Racetrack cavity BPM design can be used to suppress the cross-talk. With the nonlinear effect being ignored, transform matrix can be used to correct cross-talk. Analysis of cold test results shows that the position resolution of prototype BPM is better than 3 μm.展开更多
文摘For a long pulse free-electron laser(FEL)in the low gain regime,an approximate expression is given to describe the optical field gain from the small signal to the weak saturation.The result is shown to agree with those from a 1-D computer simulation.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10875117 and 11005106)National "985 Project" (Grnat No. 173123200402002)+1 种基金China Postdoctoral Science Foundation (Grant No. 20100470853)"the Fundamental Research Funds for the Central Universities"
文摘An S-band cavity BPM is designed for a new injector in National Synchrotron Radiation Laboratory. A re-entrant position cavity is tuned to the TM110 mode as position cavity. Cut-through waveguides are used as pickups to suppress the monopole signal. Theoretical resolution of this design is 31 nm. A prototype cavity BPM system is manufactured for off-line cold tests. The wire scanning method is used to calibrate the BPM and estimate the performance of the on-line BPM system. A cross-talk problem has been detected during the cold test. Racetrack cavity BPM design can be used to suppress the cross-talk. With the nonlinear effect being ignored, transform matrix can be used to correct cross-talk. Analysis of cold test results shows that the position resolution of prototype BPM is better than 3 μm.
