Abstracts Brochure - CERN

WEPLS — Poster Session 28-Jun-06 16:00 - 18:00
New Measurements of Sextupole Field Decay and Snapback Effect on Tevatron Dipole
Magnets
To perform detailed studies of the dynamic
effects in superconducting accelerator magnets,
a fast continuous harmonics measurement
system based on the application of a
G. Velev, P. Bauer, J. DiMarco, M.J. Lamm, D.F. Orris, P. Schlabach,
C. Sylvester, M. Tartaglia, J. Tompkins (Fermilab)
digital signal processor (DSP) has been built at Fermilab. Using this new system the dynamic effects in the sextupole
field, such as the field decay during the dwell at injection and the rapid subsequent "snapback" during the
first few seconds of the energy ramp, are evaluated for more than ten Tevatron dipoles from the spares pool. The
results confirm the previously observed fast drift in the first several seconds of the sextupole decay and provided
additional information on a scaling law for predicting snapback duration. The presented information can be used for
an optimization of the Tevatron and for future LHC operations.
2-in-1 Large-aperture IR Quadrupole for the LHC Luminosity Upgrade
After LHC operates for several years at nominal
parameters, it will be necessary to up- A.V. Zlobin, V. Kashikhin (Fermilab)
grade it to higher luminosity. Replacement
of the low-beta insertions with higher performance design based on advanced superconducting magnets is one of the
most straightforward steps in this direction. An interesting option for a new IR design is a double bore inner triplet
with separation dipoles placed in front of the focusing quadrupoles. This approach reduces the number of parasitic
collisions by more than a factor of three with respect to the quadrupoles-first option and allows independent field
error correction for each beam. Several designs of the 2-in-1 Nb3Sn quadrupole magnets suitable for the LHC IR
upgrade have been studied, including magnets with "cold" and "warm" iron yokes based on symmetric or asymmetric
coils. This paper describes the design concepts of 2-in-1 large-aperture IR quadrupoles and compares their major
performance parameters, including aperture, field gradient, field quality, electromagnetic stresses in the coils, and
discuss some technological aspects of magnet fabrication.
Thermal Analysis of the LHC IR Quadrupoles
The first generation of low-beta quadrupoles
for the LHC IR inner triplets based on NbTi A.V. Zlobin (Fermilab)
superconductor was developed by KEK and
Fermilab in collaboration with CERN. The magnets were designed to achieve the nominal luminosity of 1034 cm-2s-
1. They provide a nominal field gradient of 200 T/m with a 20% margin at the high luminosity insertions with 70mm
coils, and operate at 1.9K under high radiation-induced heat load. Work on the second generation of low-beta
quadrupoles based on Nb3Sn superconductor with larger aperture and larger operation margin for future IR triplets,
which would allow reliable magnet operation at luminosity up to 1035 cm-2s-1, have also been started. Paper presents
results of thermal analysis for the present and future IR triplets based on NbTi and Nb3Sn magnets with the expected
radiation induced heat depositions in the magnet coils.
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WEPLS110
WEPLS112
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