STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
KEK, Ibaraki
The University of Liverpool, Liverpool
STFC/DL/SRD, Daresbury, Warrington, Cheshire
ALICE (Accelerators and Lasers In Combined Experiments), a 35 MeV energy recovery linac based light source, is being commissioned and developed as an experimental R&D facility for a wide range of projects that could employ synchronized ultra-short (<1ps) electron bunches and light pulses. A suit of light sources includes an IR FEL, Compton backscattering (CBS) X-ray source, high power THz source and a multi-TW femtosecond laser. The full energy recovery and coherently enhanced, due to shortness of the electron bunches, THz radiation have been already demonstrated on ALICE. Completion of the first phase of the CBS x-ray source experiment and first lasing of the IR FEL by the end of 2009. Status of ALICE experimental facility and latest results on FEL, THz, and CBS development are reported in this paper.
UAD, Dundee
University of Dundee, Nethergate, Dundee, Scotland
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
Electro-optic longitudinal bunch profile monitors are being implemented on ALICE (Accelerators and Lasers In Combined Experiements) at Daresbury Laboratories and have been used to characterise the electron bunch and to provide a testbed for electro-optic diagnostic techniques. ALICE is a 20 MeV energy recovery linac based light source with a bunch length of approximately 0.4 ps and a bunch charge of 80 pC. It is being developed as an experimental test bed for a broad suite of science and technology activities that make use of electron acceleration and ultra-short pulse laser techniques. At ALICE the electro-optic station is located immediately after the bunch compressor. This location allows nearby OTR beam profile monitors and Coherent Synchrontron Radiation (CSR) diagnostics to be used for calibration and benchmarking. This range of diagnostics will be evulated for suitabililty on the Next Light Source (NLS) under development in the UK. We present data for both spectral decoding and temporal decoding of the electron bunch at different bunch compression ratios, plus a measurement of the timing jitter of the electron bunch.
FOM Rijnhuizen, Nieuwegein
University of Dundee, Nethergate, Dundee, Scotland
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
UAD, Dundee
Longitudinal electro-optic electron bunch diagnostics has been successfully applied at several accelerators. The electro-optic effect can be seen as an upconversion of the Coulomb field of the relativistic electron bunch (THz radiation) to the visible spectral range, where a variety of standard diagnostic tools are available. Standard techniques to characterise femtosecond optical laser pulses (auto- and cross-correlators) have led to the schemes that can measure electron bunch profiles with femtosecond resolution [1]. These techniques require, however, well synchronized femtosecond laser pulses, in order to obtain the desired temporal resolution. Currently, we are exploring other EO variants which require less advanced laser systems. The first results will be presented in our contribution.
[1] Berden et al. Phys. Rev. Lett. 99, 164801 (2007), B. Steffen et al. Phys. Rev. ST - Acc. Beams, 12, 032802 (2009)
STFC/RAL, Chilton, Didcot, Oxon
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
University of Dundee, Nethergate, Dundee, Scotland
The NLS project team is designing a UK-based ultrashort light pulse facility covering the whole spectrum from the terahertz to the soft X-ray. It will be based on a suite of sources including seeded FELs, conventional lasers and undulators. Experiments will frequently be multi-beam and will often depend on precise management of the pulse timings. With pulse durations of ~20fs or less the aim will be to reduce timing jitter to the 10-20fs level. In addition to the needs of the NLS’s users, stable operation of the machine itself will also require adequate timing control. In particular reproducible FEL operation will depend on good temporal overlap between the seed photons and the electron bunches. This paper covers both the underlying issues, (e.g. choice of pulse rates, passive and active timing management, requirements specification) and also the approaches taken in specific NLS areas (e.g. choice of clock and distribution system, management of electron bunch timing, management of fluctuations in beam transport paths). An overall jitter budget is presented.
