Laboratoire National des Champs Magnétiques Pulsés CNRS – INSA

detailed information on coil behaviour and lifetime. Another technical improvement was the introduction of
“home built” pneumatic switches. In a first time they replaced the (quite expensive) electro-mechanical relays
for connecting the resistance measurement system. A much bigger version has now been developed to change
the polarity of a complete generator.
In addition we have two 0.17 MJ small generators that are used for testing smaller coils or to energise multi-coil
systems.
0.15 MJ transportable generator
The 0.15 MJ transportable generator showed its versatility and its reliability in various experiments at other large
installations. To make the setup of this generator more user-friendly (the first version needed a qualified
technician to assemble the units after transport) this generator has been equipped with special high-voltage, highpower
connectors and it can now be installed by a trained scientist without opening the generator modules.
1 MJ transportable generator
The success of the 0.15 MJ unit motivated us to build a 1 MJ transportable generator. This generator is equipped
with an automatic system for polarity control that permits to change the direction of the magnetic field pulse.
This is important for magneto-galvanic measurements and experiments using circular polarised X-rays. The
generator was completely designed, built and tested in the laboratory, and is now in operation.
6 MJ transportable generator project
In order to produce field above 60 T one needs, due to the increased current density, shorter pulses than the
actual 14 MJ generator can deliver. It was decided to build or acquire a 6 MJ generator with a shorter rise time.
Design studies have been finished and a call for tender is expected to be announced soon.
“Megagauss” generator
The generator for the destructive single turn installation (‘Megagauss’) has to be very fast and be able to supply
a very large current. The assembly at the LNCMP of a 200 kJ, 60 kV, 2 MA, 0,5 µs rise time generator was
recently successfully completed. It is located inside a Faraday cage for safety reasons and to limit the
perturbation of other measurements in the building.
Summary & Outlook: coils
The standard (rapid-cooling, zylon reinforced 60 T coils) are performing well and have a typical lifetime of 500
pulses at maximum field. The production of these coils has been standardised and takes less than 3 weeks (1
week production of parts on a computerised machine, < 1 week coil winding,