by John Vandore

Looking to drive that golf ball a few yards more? Need to refrigerate some bull semen down on the farm? Seeking an alternative to cremation? Shaving another tenth of a second off that lap time?

These are just some of the diverse applications of cryogenic technologies, employing very low temperatures often associated with liquefied gases such as nitrogen, which becomes a liquid below -196C.

There are regional variations in cryogenics. In some areas you can find industrial-scale freezing of fish and hamburgers, or the use of cryogenics to make ice cream. Elsewhere, major investment is currently going into terminals for natural gas that is stored in liquid form at -162C.

The liquefied gas is transported in vast special ships, giving the UK access to new energy supplies.

However, the main thrust of Oxfordshire's long association with cryogenics remains primarily in the scientific instruments and related manufacturing arenas.

It is an enabling technology in super-conducting magnets, in space exploration and in many other fields of research, from particle physics to the study of cancer.

Cryogenics expertise is put to work in Oxford University and the research centres at Culham, the Rutherford Appleton Laboratory, and the new, adjacent Diamond synchrotron.

In the serious' cryogenics practised here, the concept of an absolute zero' temperature (close to 273 degrees below zero) comes into play, and with it, the alternative Kelvin scale of temperature.

Each Kelvin (K) equals one degree Celsius (C), but the scale starts from absolute zero, making 0K the same as -273C.

Helium is the medium of choice for scientists and engineers working with these temperatures, since it only becomes a liquid below -269C or 4K.

Given this background, it may still come as a surprise that the region around Oxford is considered to be the biggest market for liquid helium in Europe.

In addition to research activity, it is the concentration of super-conducting magnet manufacturing by companies such as Siemens Magnet Technology, Magnex, Oxford Instruments and GE which drives this demand.

The scale of this industry is in turn responsible for an exceptional network of specialist suppliers, subcontractors and consultants.

Industrial gas companies operate from centres in Didcot, Thame and Eynsham, while related vacuum, electronics, component and equipment specialists are dispersed around the county.

A study of the high-tech economy in Oxfordshire dubbed the development of this community Cryogenics Valley' in the style of other world-class clusters.

However it came about, the result is a unique network of inter-related science, manufacturing and infrastructure.

How low can you go?' is a question which exercises those plying their trade at the frontier of cryogenic research, and it is indeed possible to attain temperatures so close to absolute zero - within a thousandth of a Kelvin - that they are extremely difficult to measure.

Another helium-dependent device which helps scientists achieve such conditions is currently celebrating its 40th anniversary.

The world's first commercial dilution refrigerator was produced by Oxford Instruments in 1966.

Four decades of refinement later, the dilution refrigerator is an enabling tool for other local centres of excellence in nanotechnology and quantum computing.

As cryogenics continues to meander further from the laboratory, it remains a technology to be treated with respect.

There are issues of safety, for example, which arise not only from low temperatures per se. Evaporation of trapped cryogenic liquids can give rise to dangerously high pressures and may also pose the risk of asphyxiation in enclosed spaces.

Having portrayed Oxfordshire's special role in cryogenics, it is with a tinge of regret that I record that our neighbours in Berkshire may have taken a lead in one respect.

At The Fat Duck, down the valley in Bray, master chef Heston Blumenthal has adopted liquid nitrogen as a favourite ingredient in his special brand of haute cuisine or molecular gastronomy' (influenced nevertheless by Oxford University).

At least with nitrogen in the souffl there's no need to count the calories.

n Contact: British Cryogenics Council, www.bcryo.org.uk n This page is complied by the Oxford Trust, www.oxtrust.org.uk