Coldmass for Lhc Dipole Insertion Magnets. Page: 1 of 4
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BNL-69157
Submitted to MT-15, Fifteenth International Conference on Magnet Technology, Beijing, China, October 20-24, 1997.
Coldmass for LHC Dipole Insertion Magnets*
R. Gupta', R. Alforque, M. Anerella, E. Kelly, S. Plate, C. Rufer, P. Wanderer, E. Willen, K.C. Wu
Brookhaven National Laboratory, Upton, NY 11973, USAAbstract-Brookhaven National Laboratory (BNL) is build-
ing a number of magnets for the insertion regions of the Large
Hadron Collider (LHC). This paper presents the magnetic de-
sign and the expected field quality in 2-in-l dipole magnets. A
unique feature of this coldmass design is the use of an oblate-
shaped yoke. This concept permits a variety of BNL-built mag-
nets to have a similar overall design and allows the LHC main
dipole cryostat, post, etc., to be used in these magnets. The pro-
posed oblate-shaped yoke also offers a way to reduce the overall
cryostat size in future magnets. The dipoles will use the same 80
mm aperture coils as used in the Relativistic Heavy Ion Collider
(RHIC) dipole magnets, but will use stainless steel collars. The
design presented here is still evolving and the magnets may be
built differently than described here.
I. INTRODUCTION
As a part of the US-CERN collaboration for the Large
Hadron Collider, the Brookhaven National Laboratory has
proposed building a number of superconducting insertion
magnets. There are five types of 2-in-1 dipoles and one type
of single aperture dipole. The overall design parameters of
these magnets are given in Table I. The differences between
various types of magnets (D1, D2, D3a, D3b, D4a and D4b)
are given in Table II. This table also gives the proposed
number of magnets (including spares). The actual number
and type of magnets to be built is, however, subject to overall
budget limitations. All 2-in-1 dipoles will have the field in
the same direction but with a different value of spacing be-
tween the two apertures. In the design presented here, all
magnets will use stainless steel collars. A detailed description
of the overall design may be found in the reference manual
[1].
'Current Address : Lawrence Berkeley National Laboratory, MS 46-161,
Berkeley, CA 94720 USA.II. OVERALL YOKE AND CRYOSTAT GEOMETRY
Figure 1 shows the coldmasses of all 2-in-1 magnets to-
gether with the coldmass of D3a magnet inside the cryostat.
In the original proposal, the dipoles D3a and D3b were con-
sidered to have two separate 1-in-1 coldmasses, whereas D4a
and D4b were designed with 2-in-1 coldinasses. In the design
presented here, all magnets would be 2-in-1 type coldmasses
and all would have a similar yoke outer surface. The yoke is
made oblate so that it can fit inside the LHC main dipole
cryostat. Whereas the horizontal dimensions are determined
by the magnetic and mechanical design, the vertical dimen-
sions are made equal to the yoke outer diameter of the LHC
main dipole magnet. This permits the use of LHC cryostat,
post and other components with only minor modifications.
In a small scale production such as this, a large fraction of
magnet cost is determined by the detailed engineering, tool-
ing and magnet R&D. The insertion magnets being built at
BNL use 80 mm aperture coils developed for RHIC dipoles
and cryostat and other components between the cryostat and
coldmass (post, etc.) developed by CERN for LHC dipoles.
An approach that makes the design of a number of magnets
as unifonn as possible and that modifies or adopts the geome-
try to use the detailed engineering design developed for other
magnets translates into a significant saving in design time for
this production.
The proposed oblate-shaped yoke also offers a way to re-
duce the overall cryostat size in future magnets. In most
magnets, the horizontal size is determined by the magnetic
and mechanical designs and the vertical size is determined by
the heat leak budget and post design. The two are then added
to determine the overall size. In modifying the circular yoke
shape to an oblate shape, yoke iron is removed from the ver-
tical plane, as this material does not contribute to the mag-
netic and mechanical design. The vertical space, thus saved,
can be utilized by the post and thermal shielding, reducing
the overall size. The validity of this design will be tested in
the first model magnet to be built at BNL prior to the produc-
tion run of the LHC insertion magnets.Manuscript received on October 20, 1997.
R. Gupta, Email : guptal@bnl.gov, FAX 516-344-2170
Work supported by the U.S. Department of Energy under the contract No.
DE-AC02-98CH10886.
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Gupta, R.; Alforque, R.; Anerella, M.; Kelly, E.; Plate, S.; Rufer, C. et al. Coldmass for Lhc Dipole Insertion Magnets., article, October 20, 1997; Upton, New York. (https://digital.library.unt.edu/ark:/67531/metadc733487/m1/1/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.