Laboratoire National des Champs Magnétiques Pulsés CNRS – INSA

High magnetic field development
Magnet development outcome: 2005/2009
From 2005 to 2009, the magnetic field available to researchers at the LNCMI has been increased
from 28 teslas in a 50 mm bore to 35 teslas in a 34 mm diameter bore. This result was obtained by
developing the polyhelix technology. The helix technology developed in Grenoble has proved to be able to
produce the highest continuous resistive field in the world. Undergoing project is the preparation of a magnet
with B > 30 teslas in a 50 mm bore and the standardization of the three sites 20 MW sites of the LNCMI
(M8, M9, M10) so that they could accept any high field insert. Critical points of construction have been
patented end 2007 by the laboratory to protect this efficient technology 1 . It consists of the optimization and
realization of patterns in the helix cut itself. This construction procedure is suitable to form windings well
adapted for electromagnet design (using metal alloys or massive superconductors) as the cut’s pattern can be
optimized to hold mechanical constraints that originated from electromagnetic and/or thermal constraints.
Such a design has been tested first in the 32 T magnet and is now fully operational in the 35 T magnet.
Table 1: The “high field” status of the LNCMI facility
Magnet site Magnetic field Remarks
M9 35 T in 34 mm World record for resistive magnet (March 2009)
M10 28 T in 50 mm B > 30 T planned for 2010
M8 19 T in 160 mm
From 2010, the configuration will be available on M9 and M10, M8 site
will then be free for the 42 T hybrid project
M1/M6 23 T in 50 mm Field available on two sites, 25 T version for 2010
M7 20 T in 50 mm Dedicated to applied superconductivity
M5 13 T in 130 mm Mainly applied superconductivity and magneto-sciences
Top view of the 14 helix 35 magnet of the LNCMI Optimized cut patterns have been applied in 2008 and 2009
on pair of helices that are radially cooled in series. These new
technologies are available to researchers in 2009 on the new M1,
12 MW high field site. This new design leads to a better cooling
of the inner most helices and consequently allows to apply
higher current densities on the inner most helix. The validation
of this technology has allowed to use it in the design study made
in the frame of the ESRF upgrade study for high field magnet
suitable for diffraction (cf § Magnet for diffraction studies).
Undergoing optimizations aim at reducing the mechanical stress
on the critical helices to be able to sustain the new specifications
of the 42 T CEA/CNRS hybrid project. For this we develop high field magnets that will use a combination of
the two helix technologies (namely, longitudinally and radially cooled). The first version of this “mixed
insert” is planned to be available in 2010 in a 50 mm version with a magnetic field higher than 30 T. If
successful we aim at developing a 38 Tesla magnet in a 34 mm configuration for 2011.
The successful development of the helix high field technology has permitted to propose the use of
this technology in the heart of the projects that will contribute to define the future of the LNCMI. This
technology will be combined in the future with the use of High Temperature Superconductors for the
definition of the high field projects for the period 2015/2020.
These aspects are presented in the § “Perspectives for magnet development 2010/2014”.
1Brevet
FR2923073 & WO2009053420, 2009, Bobine apte à générer un champ magnétique et procédé de
fabrication de ladite bobine
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