Abstracts Brochure - 2nd International Particle Accelerator Conference

undulator. The spectrum calculation formula for
wiggler or undulator is quite difference and
consequently obtain a big different flux density by
using the same strength parameter. So, it is no way
that the spectrum calculation of them is consistent.
Therefore, a universal formula will be developed for
the spectrum analysis for the different kinds of
insertion devices that is with large different strength
parameter (deflection parameter). Consequently, a
modified spectrum calculation formula of ID with
medium strength parameter was studied by
reviewing the difference of existing spectrum
formulas. The familiar formula of calculating
undulator spectrum was modified and can be used
on ID with arbitrary strength parameter. The
algorithm of formula modification was described.
Some relative issue, like the effect of phase error
and energy spread, and taper undulator were also
discussed herein.
Sub Classification: T15 Undulators and Wigglers
Poster Panel 22
ID: 3267 - THPC168
A New Approach on Field Error Compensation
for Superconducting Undulator,
Somjai Chunjarean (PAL, Pohang, Kyungbuk),
Ching-Shiang Hwang, Jyh-Chyuan Jan (NSRRC,
Hsinchu), Helmut Wiedemann (SLAC, Menlo Park,
California) - To reach higher photon energies in the
region of soft or hard x-rays with high photon beam
brightness in low energy storage rings,
superconducting undulators with very short period
length and high magnetic field strength are required.
Because undulator radiation comes in a line
spectrum, photons up to the 7th harmonic are
desired. The photon brightness in such harmonics is
strongly dependent on perfect periodicity of the
magnetic field. Such imperfections also appear in
conventional permanent material undulators, which
can be corrected by well developed and efficient
shimming. Unfortunately, this method cannot be
applied to superconducting undulators. Therefore,
we present a new approach to field corrections by
modification of the magnetic field saturation in each
pole. In this paper it is shown that this approach can
reduce not only the magnetic field error but also
greatly improves phase errors from period to period.
The proposed method works quite local with only
small perturbations in neighboring poles. The
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tenability is preserved for most of the field
excitations and is reduced only at extreme
parameters.
Sub Classification: T15 Undulators and Wigglers
Poster Panel 23
ID: 3075 - THPC159
Factory Acceptance Test of COLDDIAG: A Cold
Vacuum Chamber for Diagnostics, Stefan Gerstl,
Tilo Baumbach, Sara Casalbuoni, Andreas
Wolfgang Grau, Michael Hagelstein, Tomas
Holubek, David Saez de Jauregui (Karlsruhe
Institute of Technology (KIT), Karlsruhe), Cristian
Boffo, Gunther Sikler (BNG, Würzburg), Vincent
Baglin (CERN, Geneva), James Clarke, Roger
Michael Jones, Duncan Scott (Cockcroft Institute,
Warrington, Cheshire), Matthew Peter Cox, Jos
Chris Schouten (Diamond, Oxfordshire), Roberto
Cimino, Mario Commisso, Andrea Mostacci, Bruno
Spataro (INFN/LNF, Frascati (Roma)), Erik Jan
Wallén (MAX-lab, Lund), Ralf Weigel (Max-Planck
Institute for Metal Research, Stuttgart), Thomas
William Bradshaw (STFC/RAL, Chilton, Didcot,
Oxon), Ian Reginald Roy Shinton (UMAN,
Manchester) - Superconductive insertion devices
(IDs) have higher fields for a given gap and period
length compared with the state-of-the-art technology
of permanent magnet IDs. One of the still open
issues for the development of superconductive
insertion devices is the understanding of the heat
intake from the electron beam. With the aim of
measuring the beam heat load to a cold bore and the
hope to gain a deeper understanding in the
underlying mechanisms, a cold vacuum chamber for
diagnostics was built. It is equipped with the
following instrumentation: retarding field analyzers
to measure the electron flux, temperature sensors to
measure the beam heat load, pressure gauges, and
mass spectrometers to measure the gas content. The
flexibility of the engineering design will allow the
installation of the cryostat in different synchrotron
light sources. The installation in the storage ring of
the Diamond Light Source is foreseen in November
2011. Here we report about the technical design of
this device, the factory acceptance test and the
planned measurements with electron beam.
Sub Classification: T15 Undulators and Wigglers