IAP, Beijing
Wuhan University, Wuhan
It is proposed that a chirped pulse can be amplified using a free-electron laser. Chirped pulse amplification (CPA) technology is one of the major ways to get high power and ultra short FEL pulse．Linear chirped pulse amplification at single pass FEL amplifier is studied through numerical simulations using our 1D time-dependent code GOFEL-P. The processes of chirped pulses with different chirped parameters being amplified by normal FEL amplifier or the FEL amplifier with energy-chirped beam are studied. The peak power and width of the final compressed pulse with different chirped parameters have been calculated. The results show that, the normal FEL amplifier can amplify the chirped pulse, the peak power of the final compressed pulse can reach 10s GW and the width of the pulse can be 10s fs with the parameters of TTF. In the case of using the energy-chirped beam to amplify chirped pulse, the gain bandwidth of the FEL amplifier will be wider and the chirped parameter will be larger. The peak power of the final compressed pulse can even reach near 10 times larger and the width of the pulse 10 times shorter than that with normal electron beam.
CAEP/IAE, Mianyang, Sichuan
IAP, Beijing
After the first lasing in March 2005 in CAEP, the FEL-THz facility is updated ,the former thermionic cathode injector was replaced using a high brightness photo-cathode injector. The facility mainly consists of a 4.5cells photo-cathode RF-GUN injector ,a hybrid undulator and the optical oscillator cavity. Number of undulator periods is 44, the peak value of the undulator is 4900Gs ,the good aperture is 6mm .The cathode material is Cs2Te and the quadruple light is used , the width of the driving laser is 12ps， the quantum efficiency is about 1%. The commissioning of the injector is finished, the electron energy of the injector was measured and it is about 8MeV ,the energy spread is about 1% and the electron beam normalized emittance is about 9πmm.mrad. The charge is about 100pC and up to 1nC per micro-pulse , the repetition rate is 54.167MHz .The calculated wavelength of the light is about 125micron. At present ,the spontaneous emission experiment is undertaking .
