Abstracts Brochure - CERN

TUPCH105
TUPCH106
TUPCH107
27-Jun-06 16:00 - 18:00 TUPCH — Poster Session
Performance of a Nanometer Resolution Beam Position Monitor System
S. Walston, C.C. Chung, P. Fitsos, J.G. Gronberg (LLNL) S.T. Boogert
(Royal Holloway, University of London) J.C. Frisch, J. May, D.J.
McCormick, M.C. Ross, S. Smith, T.J. Smith, G.R. White (SLAC)
H. Hayano, Y. Honda, N. Terunuma, J.U. Urakawa (KEK) Y.K.
Kolomensky, T. Orimoto (UCB) A. Lyapin, S. Malton, D.J. Miller
(UCL) R. Meller (Cornell University, Department of Physics) M.
Slater, D.R. Ward (University of Cambridge) V.V. Vogel (DESY)
190
International Linear Collider (ILC) interaction
region beam sizes and component position
stability requirements will be as small
as a few nanometers. It is important to the
ILC design effort to demonstrate that these
tolerances can be achieved – ideally using
beam-based stability measurements. It has
been estimated that RF cavity beam position
monitors (BPMs) could provide position
measurement resolutions of less than one nanometer and could form the basis of the desired beam-based stability
measurement. We have developed a high resolution RF cavity BPM system. A triplet of these BPMs has been installed
in the extraction line of the KEK Accelerator Test Facility (ATF) for testing with its ultra-low emittance beam.
The three BPMs are rigidly mounted inside an alignment frame on variable-length struts which allow movement in
position and angle. We have developed novel methods for extracting the position and tilt information from the BPM
signals including a calibration algorithm which is immune to beam jitter. To date, we have been able to demonstrate a
resolution of approximately 20 nm over a dynamic range of ± 20 microns. We report on the progress of these ongoing
tests.
SPEAR 3 Diagnostic Beamlines
SPEAR 3 has two diagnostic beam lines: an
W.J. Corbett, C. Limborg-Deprey, W.Y. Mok, A. Ringwall (SLAC) x-ray pinhole camera and a visible/UV laboratory.
The pinhole camera images ∼8 keV
dipole radiation on a phosphor screen with a remote computer to capture digital profile images. The visible/UV
beam line features an 8 mm high GlidCop ’cold finger’ to remove the x-ray core of the beam. The remaining light
is deflected horizontally onto an optical bench where it is focused via reflective (Cassegrain) or refractive optics.
The visible beam is then split into branch lines for a variety of experimental applications. This paper describes the
experimental arrangement, data processing algorithms and measurements obtained with both systems.
Reconstruction of the Four Dimensional Horizontal and Longitudinal Phase Space Distribution
of an Electron Beam
Understanding and optimizing the beam dy-
H. Loos, J. Castro, D. Dowell, S.M. Gierman, J.F. Schmerge (SLAC) namics in high brightness electron accelerators
not only requires the measurement of
the 6-D beam ellipse, but also the details of the phase space distribution. By combining longitudinal and transverse
phase space tomography in a dipole spectrometer the four-dimensional distribution can be resolved. We report on
experiments at the Gun Test Facility (GTF) at SLAC where we measure the energy resolved horizontal beam distribution
while simultaneously varying the longitudinal time-energy correlation and the horizontal phase advance to
reconstruct the horizontal-longitudinal phase space distribution.