| Paper | Title | Other Keywords | Page | ||
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| IT04 | Review of Emittance and Stability Monitoring Using Synchrotron Radiation Monitors | instrumentation, diagnostics, emittance, synchrotron | 16 | ||
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Different techniques of emittance and stability monitoring using bend
magnet and undulator radiation will be reviewed. Besides imaging methods
for emittance monitoring , the problem of XBPM's used for the measurement
of the centre of mass position of the undulator beams will be treated in
detail. The key feature of these monitors is a careful electron optical
design to take account of gap dependent changes of the shape and photon
energy of the undulator beam as well as spurious signals from dipoles and
high heat load. The reason for the fact that these monitors work well on
low energy machines like BESSY II but often fail due in high energy
machines will be demonstrated by experimental results obtained on
different types of BESSY II insertion devices such as undulators,
wavelength shifters, multipole wigglers and electromagnetic undulators.
Experimental results of global and local orbit monitoring and a proof of
principle of a XBPM-based local feedback will be shown.
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| CT09 | X-Ray Interference Methods of Electron Beam Diagnostics | instrumentation, diagnostics, emittance, ESRF | 88 | ||
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Electron beam diagnostics methods based interference and diffraction of
synchrotron radiation (SR) in hard X-ray range will be discussed. Two
simple optical schemes providing X-ray interference patterns highly
sensitive to transverse size of the emitting electron beam, will be
considered. For each scheme, the visibility of fringes in the pattern
depends on transverse size of the electron beam. However, the pattern is
also determined by the scheme geometry, shape and material of diffracting
bodies. Therefore, for correct interpretation of the experimental
results, high-accuracy computation of SR emission and propagation in the
framework of physical optics should be used. Examples of practical
measurements and processing of the results are presented.
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| CT10 | Beam Charge Asymmetry Monitors for Low Intensity Continuous Electron Beam
Work supported the Southeastern Universities Research Association (SURA) which operates the Thomas Jefferson National Accelerator Facility (JLAB) for the U.S. Department of Energy under contract DE-AC05-84ER40150 |
instrumentation, diagnostics, JLAB | 91 | ||
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Experimental Hall B at Jefferson Lab (JLAB) typically operates
with CW electron beam currents in the range of 1-10 nA. This
low beam current coupled with a 30 Hz flip rate of the beam
helicity required the development of new
devices to measure and monitor the beam charge asymmetry.
We have developed four independent devices with sufficient
bandwidth for readout at 30 Hz rate: a synchrotron
light monitor (SLM), two backward optical transition radiation
monitors (OTR) and a Faraday Cup. We present the
results from the successful operation of these devices during
the fall 2000 physics program. The reliability and the
bandwidth of the devices allowed the control of the current
asymmetry at the source laser by means of a feedback loop.
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| PS17 | Beam Size Measurement of the Spring-8 Storage Ring by Two-Dimensional Interferometer | instrumentation, diagnostics, SPring-8, emittance | 142 | ||
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Two-dimensional interferometer using visible
synchrotron radiation was developed in order to measure
beam sizes at a source point in a bending magnet of the
SPring-8 storage ring. The theoretical background of this
method is described in the framework of wave-optics.
Assuming designed optics parameters, transverse
emittance was evaluated from measured beam size.
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| PS18 | Planned X-Ray Imaging of the Electron Beam at the SPRING-8 Diagnostics Beamline BL38B2 | instrumentation, diagnostics, SPring-8, emittance | 145 | ||
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X-ray imaging observation of the electron beam is
planned at the SPring-8 storage ring diagnostics beamline
BL38B2 to evaluate small vertical emittance. The
resolution target is 1 micron of electron beam size (1s).
The synchrotron radiation from a dipole magnet source
will be imaged by a single phase zone plate.
Monochromatic X-ray with energy of 8keV will be
selected by a double crystal monochromator. The
magnification factor of the zoneplate is 0.27, and an X-ray
zooming tube will be used as a detector to compensate
for demagnification.
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| PS19 | Status of the Delta Synchrotron Light-Monitoring-System | instrumentation, diagnostics, DELTA, controls | 148 | ||
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Synchrotron radiation sources like DELTA need an optical monitoring
system to measure the beam size at different points of the ring with high
resolution and accuracy. An investigation of the emittance of the storage
ring can also be done by these measurements.
Scope of this paper is the investigation of the resolution limit of the
different types of optical synchrotron light monitors at DELTA, a third
generation synchrotron radiation source. At first the normal synchrotron
light monitor is analysed. The minimum measurable electron beamsize at
DELTA is about 80μm. Emphasis is then put on a special synchrotron
light interferometer, developed for DELTA, which has been built up and
tested. This interferometer uses the same beamline and can measure
beamsizes down to about 8μm. So its resolution is about ten times
better and sufficient for the expected small vertical beamsizes at DELTA.
Measurements of the electron beamsize and emittance were done with both
(synchrotron light monitor and interferometer) at different energies.
The image processing system based on a PC Framegrabber generates a
gaussian fit to the images from different synchrotron light-monitors and
calculates the beamsizes and positions.
An investigation of possible reasons of beam movements will be appended,
because the theoretical values of the present optics are smaller than the
measured emittance.
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| PM20 | A High Dynamic Range Bunch Purity Tool | instrumentation, diagnostics, ESRF, emittance | 216 | ||
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The European synchrotron radiation facility uses a
stored electron beam in order to produce x-rays for the
study of matter. Some experiments make use of the time
structure of the x-ray beam which is a direct reflection of
the time structure in the electron beam itself. Avalanche
photo-diodes have been used in an x-ray beam in a photon
counting arrangement to measure the purity of single or
few bunch filling modes. Conventional techniques
measuring the photon arrival times with a time to
analogue converter (TAC) achieve dynamic ranges in the
10-6 range. We report here the use of a gated high count
rate device achieving a measurement capability of 10-10.
Such high purity filling modes are required in synchrotron
light sources producing x-ray pulses for experiments
looking at very weak decay signals as seen in M”ssbauer
experiments..
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