| 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, photon |
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 tube’s 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 tube’s 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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| CT08 |
Adaptive Optics for the LEP 2 Synchrotron Light Monitors
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synchrotron, extraction, radiation, synchrotron-radiation |
77 |
| |
- G. Burtin, R.J. Colchester, G. Ferioli, J.J. Gras, R. Jung, J.M. Vouillot
CERN, Geneva, Switzerland
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The image obtained with the LEP synchrotron
radiation telescopes deteriorates, giving multiple and
deformed images, when the beam energy goes beyond
80 GeV at beam currents above 2 mA. This problem is
due to the deformation of the light extracting beryllium
mirror, by as little as 1 mm, and had been predicted at
the design stage. To overcome this problem, several
changes together with an adaptive optics set-up have
been introduced. These essentially consist of a
cylindrically deformable mirror to compensate the
cylindrical deformation of the beryllium mirror and a
movable detector to compensate the spherical
deformation. Both components are continuously
adjusted as a function of beam current and energy.
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| CT11 |
The OTR Screen Betatron Matching Monitor of the CERN SPS
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injection, betatron, emittance, scattering |
90 |
| |
- C. Bovet, R.J. Colchester, G. Ferioli, J.J. Gras, R. Jung, J.M. Vouillot
CERN, Geneva, Switzerland
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In order to satisfy the stringent emittance
requirements of LHC, betatron matching monitors,
based on multiturn beam profile measurements, have
been proposed for the SPS and LHC. A test monitor
has been installed for evaluation in the CERN SPS first
in 1996 and improved in 1997. It is based on an OTR
screen and a fast beam profile acquisition system. It
has been used with proton beams to assess the quality
of the betatron matching from the PS to the SPS in
1998. Experience and results are presented.
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