This record level of 542 hours of
uninterrupted user beam time significantly
exceeded the 360 hours reached during
the year 2011.
Three other record levels were exceeded:
1/ the highest efficiency during a run
(99.4 %); 2/ the longest mean time
between failures during a single run (332
hours) and 3/ during a year (68 hours).
Throughout the 35 weeks of operation, an
efficiency above 99 % has been obtained
during 21 weeks, 9 of which reaching
100 %. The praiseworthy reliability and
performance have to be credited to the
teams working around the accelerator
facilities.
With respect to the storage ring
equipment, an unexpected high rate
of radiation-induced damages was
discovered. Detailed investigations
enabled us to understand that the dipole
synchrotron radiation (less than 10 %) is
intercepted by the so-called aluminium
“quadrupole” vacuum chambers; X-ray
fluorescence is then emitted by the
material components of their NEG coating;
the energy of theses X-rays is too high
to be significantly attenuated by the
aluminium material [1]. In order to have a
full characterisation of this phenomenon
and to devise ways to reduce this
detrimental effect, a dedicated free dipole
exit port has been recently equipped with
diagnostics and different types of vacuum
chamber material with and without NEG
coating.
Concerning the insertion devices, the
commissioning of the fast switching
Apple-II type 65 mm period EMPHU
undulator [2] has required a lot of efforts
in order to reach satisfactory results in
term of beam position stability for all its
modes of operation. The commissioning
of the newly installed W164 wiggler
(cf page 138) is going on; it will serve
both as a radiation source for the PUMA
beamline and as a modulator for the
femtoslicing project.
Finally, since October 2013 a new optics
is in operation allowing the suppression
of the excess of activation in the short
straight section (SDC15) region induced
by particle losses due to the beam lifetime.
In addition, the sensitivity to possible skew
quadrupole failures has been discarded
and the routinely injection efficiency and
beam lifetime are around 80 % and 13 h
(for a 430 mA stored current) respectively
exhibiting an increase by about 20 % with
respect to the previous optics settings
(cf page 136).
Machine Operation
ASSOCIATED PUBLICATION
J.-F. Lamarre*, X. Delétoille, L. S. Nadolski
and A. Nadji
*Synchrotron SOLEIL, l’Orme des Merisiers,
St Aubin BP48, 91192 Gif sur Yvette Cedex,
France
CORRESPONDING AUTHOR
➌
Two subsequent record levels of uninterrupted
user beam reached during the last run of 2013
(yellow parts are machine dedicated periods)
➋
Pie chart of the distribution per
domain of the beam loss origin in 2013
REFERENCES
[1] Radiation Damages and Characterization
in the SOLEIL Storage Ring, N. Hubert et al.,
644 (IBIC2013)
[2] Highlights SOLEIL 140 (2012)
135
SOLEIL
HIGHLIGHTS
2013
