Abstracts Brochure - CERN

MOPLS — Poster Session 26-Jun-06 16:00 - 18:00
Lifetime Limit from Nuclear Intra-bunch Scattering for High-energy Hadron Beams
We derive an approximate expression for
the nuclear scattering rate inside a bunched F. Ruggiero, F. Zimmermann (CERN)
hadron beam. Application to the LHC suggests
that the loss rate due to nuclear scattering can be significant in high-energy proton or ion storage rings.
Unprecedented Quality Control Techniques applied on a Large-scale Production of Superconducting
Dipole Magnets for the LHC Project at CERN
The LHC accelerator, under construction at
CERN, is characterized by the use on a large
scale of high technology super-conducting
dipoles: the 27 km ring requires 1232 15-m
F. Savary, M. Bajko, G. De Rijk, P. Fessia, P. Hagen, E. Todesco, C.
Vollinger, E.Y. Wildner (CERN)
long dipole magnets providing a peak field of 9 tesla. The coils are wound with Rutherford-type cable based on
copper-stabilized Nb-Ti superconductors. The magnets will be operated at 1.9 K in superfluid helium. The challenge
that had to be faced has been an efficient, cost-effective and reproducible mass-production to very tight tolerances:
the field quality control must be controlled to 10 -4 and the geometry of the beam tube and magnet to 0.1 mm over
the whole length, any deviation being liable to induce delays and significant cost increase. This paper presents the
methods and tools chosen to face successfully this challenge, both contractual and adhoc, based on the experience
gained over several years of fabrication. With over 80 % of the magnets produced, it becomes possible as well to
identify the issues that would have found better solutions in view of future large scale production of similar devices.
LHC IR Upgrade: A Dipole First Option with Local Chromaticity Correction
In the framework of the LHC Luminosity Upgrade,
we develop a new layout of the inter- R. de Maria, O.S. Brüning (CERN) P. Raimondi (INFN/LNF)
action region (IR) with betastar equal to 25cm
in which the combination-separation dipoles come first with respect to the triplet assembly (dipole first) in opposition
of the nominal layout (quadrupole first). The new layout presents several advantages (separate channel for multipole
errors, straightforward crossing angle scheme, early separation of the beam). The payoff is a large beta function in the
triplet, which enhances the chromaticity and other non-linear effects. We investigate options for local chromaticity
correction and their effects on long-term stability.
A Low Gradient Triplet Quadrupole Layout Compatible with NbTi Magnet Technology
and Betastar=0.25m
The paper presents a triplet layout option
with long (ca. 100 m total triplet length), R. de Maria, O.S. Brüning (CERN)
low gradient (45 T/m to 70 T/m) quadrupole
magnets. Assuming a maximum magnet diameter of 200mm, the peak coil field at the magnet coils still remains
below 7 T which is still compatible with conventional NbTi magnet technology. The peak beta function inside the
triplet magnets reaches 18 km and the configuration therefore requires an additional chromaticity correction scheme
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