First lasing at 0.287-0.37 μm free electron lasers using an S-band electron linear accelerator with a thermionic gun

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Vol. 383; no. 2; pp. 337 - 341
• Main Authors: Tomimasu, T., Oshita, E., Okuma, S., Wakita, K., Takii, T., Koga, A., Nishihara, S., Nagai, A., Tongu, H., Wakisaka, K., Miyauchi, Y., Saeki, K., Kobayashi, A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.1996
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/S0168-9002(96)00827-3

We report on first operation of the shortest wavelength free electron lasers driven by a linear accelerator with a thermionic gun. We have proved that a medium-emittance (26 πmm mrad), medium-current (60A) but 24-μs pulse 155-MeV electron beam allows free electron laser (FEL) oscillations at 0.287-0.37 μm. The peak and average FEL powers are 1.8 MW and 4 mW at 0.35 μm. Tunable wavelength range depends on characteristic optical loss of used multilayer mirrors and agrees with gain simulations. Our results provide the confidence to proceed with shorter wavelength FEL projects using a low-emittance (πmm mrad), high-current (> 100 A) beam from a high-energy linac with a photocathode.