Harwell: from Romans and Runways to Reactors and Research Renaissance

N.J. Hance, ISBN 0-09553055-0-0, 336 pp (2006), Enhance Publishing, Oxford

Hundreds of crystallographers from many countries have carried out neutron diffraction experiments at AERE Harwell or more recently at the ISIS spallation source at the Rutherford Appleton Laboratory (RAL), Chilton, England. Other X ray scientists use the Diamond synchrotron X ray source nearby. Set up in 1946, AERE was the British secret Atomic Energy Research Establishment but the laboratory complex was always known as 'Harwell', the name of a village in Oxfordshire.

The facilities were constructed on the site of a former Royal Air Force aerodrome from which Horsa troop carrying gliders were towed at the dawn of the D-Day invasion of Normandy in June 1944. Former aircraft hangers and other RAF buildings housed AERE reactors and laboratories for many years. Historically, the Harwell Chilton plateau lies at the intersection of an old Roman road that is over 2000 years old with two long distance pathways, one of them, the Ridgeway, is over 4000 years old (which gave its name to a hostel accommodating visiting scientists).

Nick Hance, a former member of the instrument staff of the DIDO and PLUTO reactors (which supplied Harwell's steady state neutron beams from the late '50s to the '80s) has compiled a history of the Harwell Chilton site and Harwell, in particular. His book outlines historic events before the 20^th century and describes pre World War II and wartime RAF activity. It then chronicles the initial build up to a nuclear research station of worldwide reputation, the subsequent de-emphasis of nuclear research and, in the present century, the transformation to a large international science park. Hance is well qualified for this; in his 46 years on Harwell's staff, he first worked on nuclear accelerators, while his later career was in information, marketing and media relations, coupled with considerable lecturing on diverse aspects of Harwell's history. Thus he has experienced many of the changes in Harwell's culture. I still possess a copy of the user guide, dated 1973, to the Badger (neutron) diffractometer on the DIDO reactor by N.J. Hance.

Scientific distinction of the new government scientific establishment was assured by the appointment of John Cockroft as the first Director of AERE. While still directing the laboratory at Chalk River in Canada, he had from 1945 been discussing the requirements for a UK nuclear laboratory. Cockcroft's Nobel Prize (with E.T.S. Walton) came in 1952 but in 1932 he was in the same laboratory at Cambridge in which James Chadwick discovered the neutron. Unsurprisingly therefore, Cockcroft encouraged neutron scattering experiments. James Thewlis headed the early "Diffraction Branch"; absorption and extinction were investigated by George Bacon and others, utilizing the low fluxes from the early reactors. Bacon and Pease and Bacon and Curry, while not competing with Alpher, Bethe and Gamow yielded entertaining author combinations!

Later, a neutron scatterer, the charismatic Walter Marshall, became head of theoretical physics and then Deputy Director and Director of AERE (1966-1973). By this time many overseas and UK university scientists were utilising the higher steady state neutron fluxes from holes in the PLUTO and DIDO reactors, as they continue to do from ISIS. However under Marshall's Directorship, scientific services were increasingly offered to industry as the concentration on nuclear powered research steadily decreased.

By the 1980s, other directors, who included the solid state physicist Graeme Low, had to further reduce staff and encourage vigorous marketing of Harwell's commercial services. Fusion research and reactor physics had already left Harwell. In 1989, AEA Technology was launched as a consultancy and services business and subsequently privatised; from the 1990's an extensive program of decommissioning, decontamination and demolition eventually included the DIDO and PLUTO reactors familiar to neutron scientists. The most prominent and idiosyncratic building on site, the Van de Graaff generator, looking like an enormous cigar lighter, was also demolished.

Contemporary neutron scatterers now utilise ISIS, replete with target station 2; its address is Chilton but it is still on the site of the former airfield. The most prominent building on the Harwell Chilton campus is now the Diamond synchrotron X-ray source. Its appearance has been likened to that of an immense flying saucer, the most expensive single scientific investment in the UK for many years. The Harwell international science and high technology park now contains over 100 companies employing 4000 people. Despite Harwell being one of the biggest of such parks in Europe, its staff (and scientific visitors) can still enjoy a congenial rural and scenic environment. Abingdon, the nearest town and home of many Harwell workers is one of the oldest in Britain, while nearby, in racehorse training country, is the Uffington White Horse, an ancient hill carving admired by many visiting scientists.

Over the years, Harwell has engaged in a variety of scientific activities, embracing non destructive testing, advising on the treatment of chemical emergencies, and computing how a catastrophic subway fire was generated at King's Cross, London, in 1987. Such topics are among many described by Hance.

In 35 self contained chapters, illustrated by 300 historic photographs of buildings, people and equipment, Hance tells entertainingly the fascinating story of Harwell's origins, many of its non crystallographic activities during the second half of the 20^th century, and how Harwell has metamorphosed into a multi tenanted 21^st century international campus. This book should appeal, not just to those with a nostalgia about reactor neutrons, but to anyone who has enjoyed working at the facilities of Harwell or Chilton.