At the KU-FEL facility, we generate and use very intense radiation in MIR region and THz region for various user experiments. The entire facility layout is shown in Figure below.

MIR-FEL has three user stations. The first one (US#1) is for MIR-FEL diagnostics and simple irradiation. The second one (US#2) is the pump-probe experiment station, where 4-K-closed-cycle He cryostat, ns-Nd:YAG and ps-Nd:YAG are available together with MIR-FEL. The third one (US#3) is multi-purpose experiment station, where users can bring their experimental apparatus to a optical table. Now US#3 is occupied by a spTPO and not available for user experiments.

THz-CUR has no user stations now. User experiments of THz-CUR is performed a optical table very close to the source. Because of radiation hazard, users must operate samples with remote control.

Schematic diagram of facility layout

The performances of the radiation sources are listed in the table below.

MIR-FEL has two operation mode; thermionic cathode operation & photocathode operation.

In normal user experiments are performed with the thermionic cathode operation. In this operation, about 3-GHz micropulse rep. rate is available with lower micropulse enregy.

The photocathode operation is under development. The micropulse rep. rate is 1/96 of thermionic operation but higher micropulse enregy is available. This is good for non-linear spectroscopy because of less heat effect to the sample with same peak fluence. The photocathode operation requires special tuning of MIR-FEL. Please make contact to facility manager (H. Zen) if you want to use photocathode operation for your experiment.

The wavelength dependence of the macropulse energy measured at US#1 of MIR-FEL is shown in Figure below. The highest macropulse energy available at US#1 is 40 mJ at 9 micro-m. The absorption by water vapor and carbon dioxide can be mitigated by filling the nitrogen gas to a transport line of MIR-FEL.

MIR-FEL macro-pulse energy as the function of peak wavelength