Abstracts Brochure - CERN

TUPCH041
TUPCH042
TUPCH043
27-Jun-06 16:00 - 18:00 TUPCH — Poster Session
the necessary resolution of the BPM utilising ± 7-bit oscilloscope, the difference signal is amplified by G>1 times
relative to the sum signal. A beam intensity normalisation algorithm for position calculation is described, based on
time correlation of the sum and difference signals. For a ’digital’ BPM, a general sampling resolution expression is
derived. It is shown that for given amplitude sampling jitter and time sampling jitter, a best achievable resolution
is decided by magnitudes of the Common Mode residue and its derivative on the digitiser input. The processing
algorithms and MATLAB scripts designed for synchronisation, calibration, beam-based resolution measurement and
beam jitter measurement, are described. Results of processing of multi-bunch train data measured at the KEK ATF
Extraction Line are presented.
Electro-optic Diagnostics on the Daresbury Energy Recovery Linac
S.P. Jamison, S.P. Jamison (CCLRC/DL/ASTeC) W.A. Gillespie, P.J.
Phillips (University of Dundee) A. MacLeod (UAD)
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An electro-optic longitudinal bunch profile
monitor is being implemented on the 4GLS
prototype energy recovery linac (ERL/p) at
Daresbury Laboratories and will be used
both to characterise the electron bunch and to provide a testbed for electro-optic techniques. The electro-optic
station is located immediately after the bunch compressor, and within the FEL cavity; its location allows it to draw
on nearby beam profile monitors and CTR and CSR diagnostics for calibration and benchmarking. We discuss the
implementation and planned studies on electro-optic diagnostics with this diagnostic station.
Background Determination and Long-wavelength Rejection during a Recent Smith-Purcell
Experiment at 45-50MeV
V. Blackmore, W.W.M. Allison, G. Doucas, C. Perry (OXFORDphysics)
P.G. Huggard (CCLRC/RAL) M.B. Johnston (University of
Oxford, Clarendon Laboratory)
Accurate determination of the longitudinal
profile of a bunch by means of coherent
Smith-Purcell radiation is dependent on the
rapid determination and subtraction of the
non-SP background radiation. High quality
far-infrared filters are also an essential requirement for the suppression of the long-wavelength component of the
background. The poster presents the details of the optical components (Winston cones and filters) developed in
connection with our recent experiments on the FELIX facility. We also present the details of the detector/electronics
arrangement for this experiment.
Longitudinal Bunch Profile Determination at 45-50MeV Using Coherent Smith-Purcell Radiation
G. Doucas, W.W.M. Allison, V. Blackmore, C. Perry (OXFORDphysics)
P.G. Huggard (CCLRC/RAL) M.B. Johnston (University of
Oxford, Clarendon Laboratory) M.F. Kimmitt (University of Essex,
Physics Centre) B. Redlich, A.F.G. van der Meer (FOM Rijnhuizen)
The longitudinal profile of 45-50MeV electron
bunches at the FELIX facility has been
determined by means of coherent Smith-Purcell
radiation. Detection of the emitted radiation
was achieved by means of an array
of room temperature pyroelectric detectors.
The paper discusses the main experimental issues of this technique, such as accurate determination of the background
and efficient collection of the SP radiation. The strengths and limitations of the technique are discussed in