Single-bunch and multibunch electron beam generation for FEL experiments with the 38 MeV L-band linear accelerator at ISIR

The generation of multibunch electron beams used for FEL oscillation experiments with the 38 MeV L-band linear accelerator at The Institute of Scientific and Industrial Research has been studied. Originally, the components of the accelerator system have been optimized for generating a high-brightness single-bunch beam. The operational conditions of the system have been investigated for a multibunch beam. A multibunch beam with a macropulse length of 4 μs has been accelerated at energies of 17 to 19 MeV. The latter part of the pulsed beam with a length of 1.8 μs has an energy spread of 1.8%. The charge per bunch is 2 nC. The beam of this part has been successfully used for oscillation experiments at a wavelength of 32 to 40 μm.