Prospects for high power linac coherent light source (LCLS) development in the 1000 A{minus}1 A wavelength range
- Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)
- Department of Physics, University of California (UCLA), Los Angeles, California 90024 (United States)
- Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
- Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)
- Istituto Nazionale di Fisica Nucleare, Sezione di Milano, 20133 Milano (Italy)
Electron bunch requirements for single-pass saturation of a Free-Electron Laser (FEL) operating at full transverse coherence in the Self-Amplified Spontaneous Emission (SASE) mode include: a high peak current, a sufficiently low relative energy spread, and a transverse emittance {epsilon}[r-m] satisfying the condition {epsilon}{le}{lambda}/4{pi}, where {lambda}[m] is the output wavelength of the FEL. In the insertion device that induces the coherent amplification, the prepared electron bunch must be kept on a trajector sufficiently collinear with the amplified photons without significant dilution of its transverse density. In this paper we discuss a Linac Coherent Light Source (LCLS) based on a high energy accelerator such as, e.g., the 3 km S-band structure at the Stanford Linear Accelerator Center (SLAC), followed by a long high-precision undulator with superimposed quadrupole (FODO) focusing, to fulfill the given requirements for SASE operation in the 1000 A{minus}1 A range. The electron source for the linac, an RF gun with a laser-excited photocathode featuring a normalized emittance in the 1--3 mm-mrad range, a longitudinal bunch duration of the order of 3 ps, and approximately 10{sup {minus}9} C/bunch, is a primary determinant of the required low transverse and longitudinal emittances. Acceleration of the injected bunch to energies in the 5--25 GeV range is used to reduce the relative longitudinal energy spread in the bunch, as well as to reduce the transverse emittance to values consistent with the cited wavelength regime. Two longitudinal compression stages are employed to increase the peak bunch current to the 2--5 kA levels required for sufficiently rapid saturation. The output radiation is delivered, via a grazing-incidence mirror bank, to optical instrumentation and a multi-user beam line system. Technological requirements for LCLS operation at 40 A, 4.5 A, and 1.5 A are examined.
- Research Organization:
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- DOE Contract Number:
- AC03-76SF00515
- OSTI ID:
- 72778
- Report Number(s):
- CONF-940592-; ISSN 0094-243X; TRN: 95:015561
- Journal Information:
- AIP Conference Proceedings, Vol. 332, Issue 1; Conference: 4. international colloquium on X-ray lasers, Williamsburg, VA (United States), 16-20 May 1994; Other Information: PBD: 1 May 1995
- Country of Publication:
- United States
- Language:
- English
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