Paper |
Title |
Other Keywords |
Page |
CT03 |
500 fs Streak Camera for UV-Hard X-Rays in 1 kHz Accumulating Mode with Optical 'Jitter Free' Synchronisation
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laser, accumulation, acceleration, optics |
54 |
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- K. Scheidt, G.A. Naylor
ESRF, The European Synchrotron Radiation Facility, Grenoble, France
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The development at the ESRF of a jitter-free, laser
triggered Streak Camera has now yielded time resolution
results as short as 460 fs while operating in accumulating
mode. The so-called jitter-free synchronisation between
the laser light and the Streak Camera is performed
through a GaAs photo-switch in a simple HV circuit that
connects directly to the Streak tubes deflection plates.
The novelty of this technique permits to obtain
excellent dynamic range measurements in a shot-to-shot
accumulation of ultra fast (laser stimulated) events at up
to 1kHz without degrading the time resolution.
Important insight was obtained on the quality of this
optical synchronisation and its dependence on the laser
characteristics, the switch circuit, and the structure of the
GaAs switch itself. This permitted to suppress the jitter
causes and today the 500 fs limitation is imposed by the
streak tubes intrinsic time resolution. This work was
done by measuring (with Au or Pd photo-cathodes) the
3rd harmonic (i.e. 267 nm) of a 100 fs Ti:Saph laser.
Also important progress was made with the reliability
of the photo-switch and problems of HV break-down and
structural degradation have been completely resolved.
Since the principal use of this system at the ESRF is in
ultra-fast X-ray diffraction experiments the
exchangeable photo-cathode structure of this tube covers
the entire UV-to-X-rays spectrum. The QE of various
photo-cathode materials was measured in the 8-30 keV
range.
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CT04 |
Bunch Length Measurements in LEP
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pick-up, synchrotron, impedance, monitoring |
59 |
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- A.J. Burns, H. Schmickler
CERN, Geneva, Switzerland
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For many years a streak camera has been used for
observing the longitudinal distribution of the particles in
any LEP e+ or e- bunch (5-50 ps r.m.s. length) on a turn
by turn basis, using synchrotron light. In 1996, a
comparison made with the longitudinal vertex
distributions of 3 LEP experiments allowed the
identification and elimination of certain systematic errors
in the streak camera measurements. In 1997, a new bunch
length measurement technique was commissioned that
uses the high frequency slope of the bunch power
spectrum from a button pickup. In 1998, this new method
was confronted with measurements from the streak
camera and the LEP experiments. The measurements
made in 1996 and 1998 are presented, with emphasis on
the calibration of the two instrumental methods and their
respective precision and limitations.
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CT05 |
Daresbury SRS Positional Feedback Systems
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feedback, dipole, multipole, wiggler |
64 |
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CT12 |
Preliminary Test of a Luminescence Profile Monitor in the CERN SPS
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proton, vacuum, ion, injection |
95 |
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- J. Camas, R.J. Colchester, G. Ferioli, R. Jung, J. Koopman
CERN, Geneva, Switzerland
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In order to satisfy the tight emittance requirements of
LHC, a non-intercepting beam profile monitor is needed
in the SPS to follow the beam emittance evolution during
the acceleration cycle from 26 to 450 GeV. Beyond 300
GeV, the synchrotron light monitor can be used. To cover
the energy range from injection at 26 GeV to 300 GeV, a
monitor based on the luminescence of gas injected in the
vacuum chamber has been tested and has given
interesting results. This monitor could also be used in
LHC, where the same problem arises. Design and results
are presented for the SPS monitor.
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PS19 |
Photon counting detectors for fill structure measurements at visible wavelengths
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storage-ring, single-bunch, diagnostics, electron |
144 |
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- H.L. Owen
CLRC, Daresbury Laboratory, Warrington, UK
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When making accurate measurements of the relative
populations of electron bunches in a storage ring, notably
in light sources operating with only a single bunch filled,
the method of time-correlated single photon counting
gives the greatest dynamic range. The timing resolution
and background noise level of the photon detector
employed is critically important in determining the overall
performance of the system; hitherto the best performance
has been obtained detecting X-ray photons using
avalanche photodiodes. On the SRS at Daresbury a visible
light diagnostic station offers greater ease of access to
instrumentation and operational advantages. A review is
given of the detector types which have been employed,
and the performances which can be obtained using visible
light.
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