The following is (belatedly!) the text of University of Sheffield Press Release 2/98 (January 1998):


John Battle, Science, Energy and Industry Minister, will be visiting Cleveland Potash's Boulby Mine on Monday 12 January 1998, to be shown research undertaken by the UK Dark Matter Collaboration. Scientists from the member institutions (University of Sheffield; CLRC Rutherford Appleton Laboratory, Oxfordshire; and Imperial College, London) will demonstrate the methods used to investigate the presence of 'dark matter' in the universe.

Every spiral galaxy is surrounded by unseen matter, which holds the stars in place by gravity and prevents the whole system from flying apart. Cosmologists believe that this `dark matter' is so common that it makes up to 99 per cent of the universe. The UK Dark Matter Collaboration is actively searching for these tiny sub-atomic particles, that are known as WIMPs (Weakly Interacting Massive Particles).

WIMPs are difficult to distinguish from other cosmic particles bombarding the Earth, so the research work is carried out in the deepest mine in Europe - the Boulby Mine, a working potash mine, run by Cleveland Potash Ltd. The mine has large workings at a depth of 1,100 metres, situated in rock salt. This makes the site possibly the best in the world for undertaking a search for WIMP dark matter, since it is both deep enough to stop the cosmic rays and also, thanks to the nature of the salt, low in natural radioactivity. The detecting equipment is suspended in 200 tonnes of high purity water to shield the dark matter detectors from this radiation.

Looking forward to the visit, Mr Battle comments: "The science of dark matter is extraordinary and fascinating. I am delighted to have this opportunity to see for myself the progress the team is making in its search for dark matter particles. This is a spectacular example of how well-established industry and cutting edge scientists can work closely together. By making their mine available, Cleveland Potash Ltd have ensured that British scientists have access to some of the best conditions in the world for their research."

As part of the visit, Mr Battle will present a plaque to Cleveland Potash Ltd in recognition of the company's commitment to the research project. He will be accompanied by, amongst others, Professor Sir Gareth Roberts, Vice-Chancellor of the University of Sheffield, Professor John Quenby of Imperial College, and the Project Leader, Professor Peter Smith, of CLRC Rutherford Appleton Laboratory.

Dr Neil Spooner, of the University of Sheffield, comments: "We are very pleased that John Battle is showing such an interest in this research.

"Without dark matter, our galaxy would fly apart, our Sun could not have developed in the way it has, and our very existence would be unlikely.

"For these reasons, the discovery of the nature of dark matter, whatever form it turns out to be, is of fundamental importance to our understanding of the universe. The high-tech nature of the research ensures that it also has various spin-offs in environmental monitoring and in medicine, where there is a need for scintillators with lower natural radioactivity."

Further information is available from Dr Neil Spooner, Department of Physics, tel: (0114) 222 4422, fax: (0114) 272 8079, email: or Dr John McMillan, Department of Physics, tel: (0114) 222 3534, fax: (0114) 272 8079, email: Both are also contactable via the Department of Physics' Office, tel: (0114) 222 3519.

or Professor Peter F Smith, CLRC Rutherford Appleton Laboratory, tel: (01235) 445 46, email:


Notes For Editors

The UK Dark Matter Collaboration has been in existence since 1989. It is a consortium of astrophysicists and particle physicists, conducting experiments with the ultimate goal of detecting rare scattering events which would occur if galactic dark matter consists largely of a new heavy neutral particle.

The principal participating members are: Imperial College of Science, Technology and Medicine; CLRC Rutherford Appleton Laboratory; and the University of Sheffield.

The programme is funded by the Particle Physics and Astronomy Research Council (PPARC), and has also received generous support from Cleveland Potash Ltd.

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