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Other Keywords |
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| PT09 |
The closed-orbit measurement system for the CERN antiproton decelerator
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antiproton, closed-orbit, pick-up, vacuum |
177 |
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- M. LeGras, L. Søby, D.J. Williams
CERN, Geneva, Switzerland
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The closed-orbit measurement system for the new
Antiproton Decelerator (AD) employs 59 electrostatic
pick-ups (PU). The intensity range from 2·1010 down to
107 particles poses challenging demands on the dynamic
range and noise of the head amplifier. A low noiseamplifier
has been developed, having an equivalent input
noise of 0.6nV/√(Hz), allowing beam positions to be
measured to ±0.5 mm with 5·106 particles. Two
different gains take care of the large dynamic range.
After amplification and multiplexing, the PU signals are
fed to a network analyser, where each measurement
point corresponds to one PU. The network analyser is
phase locked to the RF of the AD, thus acting as a
“tracking filter” instrument. An orbit measurement takes
from 0.2 to 12 s depending on the IF-bandwidth of the
network analyser, selected according to the beam
intensity, and the precision required. At the end of the
network analyser sweep the data are read via a GPIB
interface and treated by a real-time task running in a
VME based Power PC.
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| PT16 |
Status of the delta synchrotron light-monitoring-system
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synchrotron, radiation, synchrotron-radiation, emittance |
196 |
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- U. Berges, K. Wille
DELTA, Institute for Accelerator Physics and Synchrotron Radiation, University of Dortmund, Germany
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A synchrotron radiation source like DELTA needs an optical
monitoring system to measure the beam size at different
points of the ring with high resolution and accuracy.
The measurements with the present synchrotron light
monitors show that beam sizes larger than 250 μm can be
measured. The measured emittance is of the order of the
theoretical values of the optics and goes down to 8 nm rad.
The magnification of the system can simply be increased
by adding another lens to measure smaller emittances and
beamsizes down to 100 μm. In this case you still have
an optical image of the beam available, but sometimes the
position of the camera has to be adapted due to the great
magnification of the optical system. The image processing
system which is based on a VME Framegrabber makes a
two dimensional gaussian fit to the images from different
synchrotron light-monitors.
First tests with monochromatic components of the synchrotron
radiation (500 nm and 550 nm) and with short
time cameras (shutter time down to 1/10000 s) have been
performed. A two-dimensional PSD has been installed to
measure slow beam motion. To measure small beam sizes,
especially in the vertical plane, diffraction elements will be
used.
This paper gives an overview over the present installation
and the results.
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