LUX - a recirculating linac-based facility for ultrafast X-ray science

Conference · Tue Jun 29 00:00:00 EDT 2004

OSTI ID:826117

Corlett, J N; Barletta, W A; DeSantis, S; Doolittle, L; Fawley, W M; Heimann, P; Leone, S; Lidia, S; Li, D; Penn, G; Ratti, A; Reinsch, M; Schoenlein, R; Staples, J; Stover, G; Virostek, S; Wan, W; Wells, R; Wilcox, R; Wolski, A ; Wurtele, J; Zholents, A

We present recent developments in design concepts for LUX - a source of ultra-short synchrotron radiation pulses based on a recirculating superconducting linac. The source produces high-flux x-ray pulses with duration of 100 fs or less at a 10 kHz repetition rate, optimized for the study of ultra-fast dynamics across many fields of science [1]. Cascaded harmonic generation in free-electron lasers (FEL's) produces coherent radiation in the VUV-soft x-ray regime, and a specialized technique is used to compress spontaneous emission for ultra-short-pulse photon production in the 1-10 keV range. High-brightness electron bunches of 2-3 mm-mrad emittance at 1 nC charge in 30 ps duration are produced in an rf photocathode gun and compressed to 3 ps duration following an injector linac, and recirculated three times through a 1 GeV main linac. In each return path, independently tunable harmonic cascades are inserted to produce seeded FEL radiation in selected photon energy ranges from approximately 20 eV with a single stage of harmonic generation, to 1 keV with a four-stage cascade. The lattice is designed to minimize emittance growth from effects such as coherent synchrotron radiation (CSR), and resistive wall wakefields. Timing jitter between pump lasers and x-ray pulses is minimized by use of a stable optical master oscillator, distributing timing signals over actively stabilized fiber-optic, phase-locking all lasers to the master oscillator, and generating all rf signals from the master oscillator. We describe technical developments including techniques for minimizing power dissipation in a high repetition rate rf photocathode gun, beam dynamics in two injector configurations, independently tunable beamlines for VUV and soft x-ray production by cascaded harmonic generation, a fast kicker design, timing systems for providing synchronization between experimental pump lasers and the x-ray pulse, and beamline design for maintaining nm-scale density modulation.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Director, Office of Science (US)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 826117
• Report Number(s): LBNL-55621; R&D Project: Z3FALS; TRN: US0402998
• Resource Relation: Conference: 9th European Particle Accelerator Conference 2004, Lucerne (CH), 07/05/2004--07/09/2004; Other Information: PBD: 29 Jun 2004
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
43 PARTICLE ACCELERATORS
74 ATOMIC AND MOLECULAR PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACCELERATORS
BEAM DYNAMICS
COHERENT RADIATION
ELECTRONS
ENERGY RANGE
HARMONIC GENERATION
KEV RANGE
MODULATION
PHOTOCATHODES
PHOTONS
SYNCHRONIZATION
SYNCHROTRON RADIATION
ULTRAFAST ACCELERATOR X-RAY