Super magnets attract international interest

Industrial Research Limited (IRL) has developed a type of very powerful magnet – a dipole – using high-temperature superconducting (HTS) coils.

In 2009 the first magnet was shipped from New Zealand to the United States to be installed in the synchrotron at the world-renowned Brookhaven National Laboratory in New York. At the time it was the only magnet in the world designed for synchrotrons that uses HTS coils.

What exactly is a synchrotron?

A synchrotron is a type of particle accelerator in which particles move at accelerating speed around a hollow ring. The ion beam or particle path is very precisely focused by the magnetic field of the magnets, and any failure in the magnets results in the synchrotron not working.

To start the synchrotron, bursts of electrons are produced by an electron gun – a more high-tech version of the guns found in a cathode ray tube inside a TV set. These high speed, high energy electrons are accelerated through a linear accelerator – linac – to build up energy. The electrons are then sent into a small booster ring, where their energy is further increased. When the electrons reach the desired energy level, they are transferred to the hollow storage ring. As the electrons are forced to change direction by the magnets, they lose energy by emitting an intense beam of synchrotron light.

The end result is extremely bright light – millions of times brighter than the sun. This light can be split into different wavelengths across the electromagnetic spectrum, ranging from X-rays, through the visible light spectrum, to infrared radiation. The pin-point beams produced are channelled along ‘beamlines’. These can be used to probe the structure of matter and analyse a host of physical, chemical, geological and biological processes. This is an invaluable tool for new drug design, advanced manufacturing, medical imaging, materials research, mineral analysis and many other activities. The synchrotron essentially acts as a ‘super microscope’ that is so powerful it can illuminate molecules.

Money-making magnet

The man in charge of the team that developed New Zealand’s HTS magnet, Dr Donald Pooke, says 70 synchrotrons have been built or are in the planning stages of being built around the world. “So the market for these energy-saving magnets is substantial.”

HTS-110 (pronounced ‘H-T-S-one-ten’) is the name of the company that IRL formed to make and market the new magnets. IRL is a shareholder in the New Zealand Synchrotron Group, which in turn is a shareholder in the Australian Synchrotron Group. HTS-110 is well positioned to take advantage of this market.

While the smallest synchrotrons might only be a few metres in circumference, the largest is a 27 km ring of magnets. This huge machine is the Large Hadron Collider (LHC) at the CERN laboratories in Switzerland.

Find out more about the particle physics research undertaken for LHC by a team led by Dr David Krotcheck and then read about CERN and it's mini bangs.

After the LHC, the world’s most powerful currently operational synchrotron is the Tevatron, at Fermilab in the United States, with a circumference of 6 km. This synchrotron can accelerate protons and antiprotons to near the speed of light. The Brookhaven National Laboratory’s RHIC (Relativistic Heavy Ion Collider), part of its synchrotron complex, is 3.86 kms in circumference.

Money-saving magnet

Dr Pooke says the new HTS magnet is the most economical of its kind worldwide. It uses far less electricity than the alternative – magnets with copper coils – making it substantially cheaper to run.

The New Zealand HTS magnets use less than half of the energy of a copper equivalent, along with substantially less cooling water. Currently, copper coils consume 15kW of electricity and significant amounts of cooling water during operation. With each synchrotron operating 50 or more magnets, the energy usage for an entire copper ring is up to 1MW. The yearly electricity bill is in excess of NZ$1 million!

HTS-110 Senior Designer Mike Fee says that the new HTS dipole magnet uses two refrigerators to keep the magnet at operating temperature, requiring less than half the energy of a copper system. “In a full HTS installation, a centralised cooling system would realise the full energy savings of 70–80% over copper designs,” he says.