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2009 MAGNET DEVELOPMENT AND INSTRUMENTATIONMegagauss magnetic field generationThe year 2009 marks the first generation of a magneticfields in excess of 100 T at the Toulouse pulsed magnetfacility. The field has been obtained with a Megagauss generator(1 Megagauss = 100 Tesla) making use of capacitordrivensingle-turn coils to produce field pulses on a microsecondtimescale. The installation, originally developedat the Humboldt University in Berlin, between 1993 and1997, has been transferred to LNCMI-Toulouse in 2006.an improved cryostat permitting experiments at liquid-Hetemperature is underway.Prior to its recommissioning the generator has undergone amajor revision including the replacement of crucial componentsof the charge/discharge-circuit (60 kV charging supply,high-voltage switches) and the adaptation of remotecontroland security functions. In the second half of 2009the installation has been tested at moderate charging voltagesof up to 35 kV with 80 % of the nominal capacitance(16 out of 20 capacitors available). These tests have givenrise to the current 100 T field record. The field trace isshown in figure together with a simple test measurement ofthe Faraday rotation in CdS sample.This technique for generating magnetic field is destructive,in the sense that the coil explodes outwards and has to bereplaced after each pulse. However, the setup can be surroundedby an absorbing material (wood) which retains coilfragments, and notably prevents any fragments bouncingback. This means that the sample, and cryostat are not destroyedduring the pulse. Replacing the coil is a simpleoperation which can be performed quickly, and without removingthe sample or cryostat. This makes this techniquesfor generating magnetic fields practical from the point ofview of the user since many field shots are possible per day.Indeed, operation is simpler than a classical nitrogen cooledpulsed magnet since it is not necessary to wait for the coilto cool after each shot. The price to pay however, is theextremely short pulse, with only around 1µs available fordata acquisition at the maximum of the pulse.Starting from January 2010 the generator will be operated atfull capacitance and initially with moderate charging voltagesnot exceeding 45 kV. This will permit the generationof fields in excess of 150 T with little or no risk of insulationfailure. At this point the generator will be used forfirst scientific experiments making use of an optical setupfor transmission measurements in the mid-infrared rangethat has also been installed in 2009. The construction ofFigure 171: (a) Magnetic field generated with a 12×12 mm 2 single-turncoil (inner diameter × axial length) at a charging voltageof 35 kV. (b) Expanded view of the top of the magnetic field pulse.(c) Preliminary data of the Faraday rotation in a CdS sample todemonstrate the feasibility of the system for scientists.P.Y. Solane, F. Durantel, O. Portugall121