VUV free electron laser with a distributed feedback cavity
- Osaka Univ. (Japan); and others
Development of FEL to the VUV/x-ray regime is looked as one of the possible directions to its success. For eliminating the need for optical cavities, difficult to be built at that regime, we propose a VUV (50nm) SASE FEL. According to Pellegrini`s scaling law, for a 290MeV/200A e-beam passing through a 10.8m long and 2cm period wiggler, a high peak power 85.5MW and a high average brightness 2.44 X 10{sup +21} (photons/[mm{sup 2}.mrad{sup 2}.bw]) can be obtained. However, it requires {epsilon} n=2.3mm.mrad and {Delta}{gamma}/{gamma} = 0.15% about one order above the practical parameters we can realize. For enhancing the efficiency and decreasing the requirements on the e-beam quality and the wiggler length, we put forward a concept of VUV FEL with a distributed feedback cavity. In x-ray region, the natural periodicity of crystals provides strong Bragg coupling and it has been demonstrated as the parametric radiation. In vuv region, current intense research on superlattice can provide a periodical structure with a short period in 250 {Angstrom} order. High-performance vuv multilayer coatings on the inner-wall of the waveguide are used to guide the spontaneous emission and decrease the x-ray ohmic losses on the roundtrip passes. By this DFB cavity structure, it is expected to realize the lasing in a smaller size. Other practical methods such as the optical klystron for shortening the wiggler length and the tapper wiggler for enhancing the saturation power are also considered. The analytical considerations are based on the 1-D FEL equations and 1-D perturbation theory of dielectric waveguide.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- OSTI ID:
- 238686
- Report Number(s):
- BNL-61982-Absts.; CONF-9508156-Absts.; ON: DE96002729; TRN: 96:013175
- Resource Relation:
- Conference: 17. international free electron laser conference, New York, NY (United States), 21-25 Aug 1995; Other Information: PBD: [1995]; Related Information: Is Part Of 17th international free electron laser conference and 2nd international FEL users` workshop. Program and abstracts; PB: 300 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Harmonic generation in VUV/x-ray range at the Duke storage ring FEL using electron beam outcoupling
AM mode-locking of a free-electron laser oscillator