I'd have though turning it off would be an even bigger trick!
RP

On 28/11/06, Russell McMahon <apptech@paradise.net.nz> wrote:
> 1 year and counting.
> Atlas barrel toroid successfully powered up on first attempt.
>
> How hard can it be to power up a toroid???
>
> Very !!!
>
>    http://www.pparc.ac.uk/Nw/toroid.asp
>
> About 4.5 degrees above absolute zero - about the same temperature as
> space background radiation.
> 21,000 Amps.
> 1.1 GJ stored magnetic energy.
>
>
>
>
> The ATLAS Barrel Toroid consists of eight superconducting coils, each
> in the shape of a round-cornered rectangle, 5m wide, 25m long and
> weighing 100 tonnes, all aligned to millimetre precision. It will work
> together with other magnets in ATLAS to bend the paths of charged
> particles produced in collisions at the LHC, enabling important
> properties to be measured. Unlike most particle detectors, the ATLAS
> detector does not need large quantities of metal to contain the field
> because the field is contained within a doughnut shape defined by the
> coils. This allows the ATLAS detector to be very large, which in turn
> increases the precision of the measurements it can make.
>
> At 46m long, 25m wide and 25m high, ATLAS is the largest volume
> detector ever constructed for particle physics. Among the questions
> ATLAS will focus on are why particles have mass, what the unknown 96%
> of the Universe is made of, and why Nature prefers matter to
> antimatter. Some 1800 scientists from 165 universities and
> laboratories (including 12 from the UK) representing 35 countries are
> building the ATLAS detector and preparing to take data next year.
>
> The ATLAS Barrel Toroid was first cooled down over a six-week period
> in July-August to reach -269oC. It was then powered up step-by-step to
> higher and higher currents, reaching 21 thousand amps for the first
> time during the night of 9 November. This is 500 amps above the
> current needed to produce the nominal magnetic field. Afterwards, the
> current was switched off and the stored magnetic energy of 1.1 GJ, the
> equivalent of about 10 000 cars travelling at 70km/h, has now been
> safely dissipated, raising the cold mass of the magnet to -218oC.
> "We can now say that the ATLAS Barrel Toroid is ready for physics,"
> said Herman ten Kate, ATLAS magnet system project leader.
> The ATLAS Barrel Toroid is financed by the ATLAS Collaboration and has
> been built through close collaboration between the French CEA-DAPNIA
> laboratory (originator of the magnet's design), Italy's INFN-LASA
> laboratory and CERN. Components have been contributed in-kind by
> national funding agencies from industries in France (CEA), Italy,
> Germany (BMBF), Spain, Sweden, Switzerland, Russia, and the Joint
> Institute for Nuclear Research (JINR), an international organization
> based near Moscow. The final integration and test of the coils at
> CERN, as well as assembly of the toroid in the ATLAS underground
> cavern, was done with JINR providing most of the manpower and heavy
> tooling.
>
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