• M. A. Bakr, K. Higashimura, T. Kii, R. Kinjo, K. Masuda, H. Ohgaki, T. Sonobe, K. Yoshida
  Kyoto IAE, Kyoto
• Y.U. Jeong
  KAERI, Daejon
• H. Zen
  UVSOR, Okazaki

The first laser amplification at a 12 micrometre mid-infrared free-electron laser (MIR-FEL) was observed at the Institute of Advanced Energy (IAE), Kyoto University in March 2008. A 25 MeV electron beam of 17 A peak current was used for the lasing experiment. FEL gain was estimated to be 16% from the exponential growth of the laser output signal. A beam loading compensation method with an RF amplitude control both in the thermionic RF gun and in the accelerator tube was used to extend the macropulse duration against the back bombardment effect in the gun. We also developed a feedforward RF phase control to stabilize the RF phase shifts which were originated with RF amplitude control. As a result FEL saturation was observed in May 2008. The estimated FEL gain was 33% with the electron beam of 5.5 microsecond macropulse duration by use of peak current of 33 A which was deduced from GENESIS simulation. A user beamline was designed and constructed. The laser characterization at the user station will be reported in the conference. Applications of the MIR-FEL at Kyoto University in the chemistry energy research will be presented as well.

• Y. Iwasaki, T. Kaneyasu, S. Koda, Y. Takabayashi
  SAGA, Tosu
• H. Ohgaki
  Kyoto IAE, Kyoto

The procedure of accelerator modeling using orbit response matrix fitting is well known and widely adopted at many light sources, we also examined the model fitting to diagnose optics and to restore the periodicity of the storage ring optics. In the modeling procedure we used the tracking code TRACY2, because it can calculate the orbit response matrix including energy offset caused by the dipole kick. The multi-parameter fitting was carried out by using SVD algorism implemented in the Labview mathematical package. In the fitting procedure, we fixed a steering magnet field to the value obtained from the orbit measurement using screen monitor to avoid explicit solution between the steering strengths and the BPM gains. By adopting the orbit response matrix fitting, it was found that the quadrupole strength is about 3-5% larger than the calculated value obtained from magnetic measurement data and output current of the power supply. In the conference, we will report on the result of the modeling procedure and its application to the optics correction.

• T. Kii, M. A. Bakr, K. Higashimura, R. Kinjo, K. Masuda, H. Ohgaki, T. Sonobe, K. Yoshida
  Kyoto IAE, Kyoto
• H. Zen
  UVSOR, Okazaki

A short period undulator with strong magnetic field will play an important role in future light source. We proposed a new type of staggered array undulator by use of bulk high-Tc superconductor*. We have constructed a prototype of the undulator using DyBaCuO bulk superconductors and a normal conducting solenoid. In the conference, we will present results of the magnetic field measurement and discuss on the feasibility of the new type bulk high-Tc staggered array undulator.

*R. Kinjo et al., Proceedings of the FEL2008, in press.