100 years of Superconductivity

100 years ago (8 April 1911) the phenomenon of superconductivity was first observed by Dutch physicist Heike Kamerlingh Onnes at the Leiden Cryogenics Laboratory in the Netherlands. Since this discovery, superconductivity has become the underpinning technology for many of the world's most important international science experiments, with STFC instrumental in the developments:

left-hand quote markThe famous Rutherford cable developed by STFC in the seventies is now a world standard used in superconducting magnets. The same programme led the way to build dipoles (magnets which direct the beams of particles) for the Large Hadron Colliderright-hand quote mark

Shrikant Pattalwar
Senior Cryogenics Engineer
ASTeC

The Rutherford Cable

Developed by STFC, this is a multi-strand conductor used in many high field accelerator magnets today including the Large Hadron Collider and Tevatron at Fermilab.

HELIOS H1

A compact acceleration system designed for lithography applications, developed in the UK by STFC for IBM. Compact light source studies started with Oxford Instruments in 1984, followed by a formal design study exercise with Daresbury Laboratory in 1987. For their contribution, the Daresbury design team received an Inventors Award some years later.

Back in 1911, Kamerlingh Onnes found that mercury, when cooled to very low temperatures, (4.2 Kelvin or -269 Celsius) had no resistance at all when an electronic current was passed through it. Such a state makes a metal the ideal 'super' conductor of electricity because zero resistance means the electricity passes through as smoothly and efficiently as possible.

Ever since Kamerlingh Onnes's discovery, researchers at STFC and elsewhere have been looking to find materials that have superconducting properties at higher temperatures. In fact over 10,000 scientific papers have been published on the topic. Current superconductors rely on expensive cooling systems because they only become effective at such low temperatures. The ultimate aim is to find a material that becomes superconducting at room temperature and STFC is enabling this research:

A new material

In 2010 scientists using STFC's ISIS neutron source, as well as Diamond Light Source and the European Synchrotron Radiation Facility published a paper demonstrating how a new material made from metal atoms and buckyballs (tiny carbon-60 molecules shaped like a football) becomes a high temperature superconductor when it is squashed. The applied pressure shrinks the structure and overcomes the repulsion between the electrons, allowing them to pair up and travel through the material without resistance.

On behalf of the UK government, STFC is the major shareholder in Diamond Light Source and the UK sponsor of the European Synchrotron Radiation Source.

Observing ultrafast behavioural changes

Using the Artemis facility in STFC's Central Laser Facility, scientists have studied the complex changes in behaviour of a high temperature superconductor. Artemis uses laser pulses to generate ultrashort pulses of X-rays. These are then used to make an 'X-ray movie' of ultrafast changes in the way electrons are arranged in the material. The technique is used on synchrotrons to take static images of the structure of complex materials. Using a laser-based source of X-rays allows scientists to extend this technique to show how the structures change in time.

As well as being the underpinning technology for MRI scanners, superconductivity is the key in particle accelerators such as the Large Hadron Collider which is looking at what happened moments after the Big Bang, the ISIS neutron source and Diamond Light Source. It is also being used for the prototype accelerator ALICE at STFC's Daresbury Laboratory. ALICE is expected to influence accelerator technology for a variety of new applications including cancer therapies. In fact, many of STFC facilities and collaborative projects rely on superconductors:

left-hand quote markWith such high sensitivity, ALMA is able to probe our galaxy and the furthest reaches of the universe. Without superconductivity the telescope would be vastly inferior in its performance, and we would never know when it is tea time on the Moon!right-hand quote mark

Brian Ellison
ALMA UK Project Manager

Exploring the Universe

Superconductivity is enabling us to explore our Universe with the ALMA (Atacama Large Millimetre Array) telescope. The 66 telescopes that form ALMA use highly sensitive instrumentation that detects the very faint signals from outer space.

Each telescope is equipped with superconducting receiver systems and at the heart of each receiver is a minute device formed from two superconducting material layers that are separated by a very thin oxide layer. This acts as an insulator and therefore a barrier to the flow of electrons. The device is called a superconductor-insulator-superconductor (SIS) detector and the barrier is so thin that electrons from one superconductor can pass, or tunnel, though it to the other superconductor.

"Using this tunnelling effect, engineers have been able to make receivers so sensitive that, when used with the ALMA telescopes, they could detect if there was a boiling kettle located on the surface of the Moon", said ALMA UK Project manager Brian Ellison. "With such high sensitivity, ALMA is able to probe our galaxy and the furthest reaches of the universe. Without superconductivity the telescope would be vastly inferior in its performance, and we would never know when it is tea time on the Moon!"

Increasing the power of magnets at the LHC and Diamond

Inside the Large Hadron Collider (LHC) at CERN, huge magnets are used to steer the particles around the 27km accelerator. The combination of the high voltage needed to accelerate the particles and the strong field needed to conduct the electromagnets means that superconducting magnets are essential. If standard copper wires were used in the electricity transfer process, these would just burn. On behalf of the UK government, STFC is the UK sponsor of CERN.

At the Diamond Light Source a strong magnetic field is required to produce the high-energy X-rays needed for experiments. Two of the beamlines, I12 and I15 currently use superconducting magnet arrays called wigglers to produce very intense, high energy X-rays. STFC is working with Diamond to develop superconducting undulators that will produce even brighter, tunable light for these beamlines, enabling scientists to gather higher resolution data and penetrate deeper into materials.

left-hand quote markIt is fantastic news that, through STFC's Mini-IPS Scheme and our collaboration, Shakespeare Engineering is now in an excellent position to enter into what is potentially a very profitable market for UK industryright-hand quote mark

Peter McIntosh
Head of RF and Diagnostics
ASTeC

Accessing a £billion market

STFC's accelerator expertise, ASTeC, has been working with Shakespeare Engineering Ltd and Jefferson Laboratories in the USA. Together, the collaboration has reached a significant milestone by completing the design, manufacture and validation of the UK's first bulk Niobium superconducting radio frequency (SRF) accelerating structure. This enables the UK to enter a highly lucrative market that could be worth more than £1 billion globally within the next ten years. The technology is being used on ALICE, a prototype accelerator that is demonstrating energy recovery techniques. The four SRF cavities operate at a temperature of 2K.

"There is a range of current and proposed international projects for which this advanced technology is key - from next generation light sources, to a neutrino factory, muon colliders and high intensity proton facilities. It is fantastic news that, through STFC's Mini-IPS Scheme and our collaboration, Shakespeare Engineering is now in an excellent position to enter into what is potentially a very profitable market for UK industry." Peter McIntosh, Head of RF and Diagnostics at ASTeC.

More information is available in a recent press release on the ASTeC website (link opens in a new window).

Faster computers and trains that use far less power than the current ones are two of the areas that could benefit from superconductivity in the future, but in the meantime the technology has already proved a very useful discovery, and STFC continues to be at the forefront of its development.

Science and Technology Facilities Council Switchboard: 01793 442000