Obituary: Charlie Martin

CHARLIE MARTIN was a nuclear weapon designer whose reputation stood as high in the three United States nuclear weapon laboratories as at the Atomic Weapons Establishment, Aldermaston, where he spent his career. Most of that career was devoted to pulsed power, an enabling technology crucial to weapon design and demonstration, and more recently to verifying the integrity of the atomic arsenal.

A British visitor to the Sandia National Laboratory in New Mexico, where the American nuclear weapon designs are engineered into warheads, was told authoritatively in the mid-1980s: "I don't know why you've come all this way to talk about pulsed power. You've got the father of pulsed power over there."

When reported, this remark stimulated the founding of the UK Pulsed Power Club in 1986. At its inaugural meeting at the Culham Laboratory of the UK Atomic Energy Authority, UK pre-eminence in the technology was traced back to the Second World War and the post- war activities of a small group at Aldermaston led by Charlie Martin.

Martin himself told this meeting how, later, the US had come to dominate the technology because its practitioners talked freely about their problems, even when working for rival firms. "Their bosses hate it." His experience - he was a consultant to Sandia as well as an employee of the Ministry of Defence - was that every bit of help he gave US experts was repaid tenfold. His message for the new club was: "Co-operate - even when it hurts you a bit."

He made what must be one of the most open invitations Aldermaston has ever extended to the US: "Please come and talk to us." This was pursued enthusiastically by those seeking help for the US Government's Strategic Defence Initiative ("Star Wars").

Pulsed power is the technology of storing electricity and releasing it suddenly, as "thunderbolts" of enormous voltage and current, like lightning strikes. Such pulses are used to drive high-energy physics experiments, to power laser and other potential beam weapons, and to test the tolerance of complex electrical systems to lightning strikes, for example.

Nuclear weapon designers need pulsed power to provide the energy for flash radiography, whereby they can photograph inside a warhead and verify the way its 2,000 parts have been assembled. It has also been needed increasingly to verify the integrity of the nuclear stockpile since atomic testing was abandoned.

Martin, recounting his Aldermaston years to the Pulsed Power Club in 1995, told how in the early 1950s he heard that Aldermaston had been offered a linear accelerator "for free" but was minded to turn the offer down. At the time his way lay elsewhere, on designing the polonium initiator for the first UK atom bomb. He moved on to the intrinsic safety of the design - how the bomb would behave in a fire or if dropped inadvertantly, for example. Testing was done in the Australian desert at Maralinga.

But young Martin had the foresight to see how valuable the linear accelerator machine could be to weapon designers, and argued his case successfully with Sir William Cook, Aldermaston's director.

A few years later, as a member of the Warhead Hydrodynamics Division, he was given responsibility for the "relatively unloved and understaffed" machine. It became the nucleus of his pulsed power team, and the precursor of a series of big machines delivering increasingly powerful bolts of energy.

The latest, Mogul E, built in the 1990s, is claimed to be the world's most powerful flash radiography machine. Perhaps more significantly, Martin's team soon acquired a reputation for building its machines for a fraction of their equivalents in the US atomic weapons industry.

In 1995 Martin estimated that his team had spent about pounds 9m at present- day value, over 22 years, on pulsed power. It had helped pioneer a field of technology in which about 5,000 people were engaged. He also believed pulsed power had contributed to maintaining the balance of deterrence during a vital period.

At Christmas 1994 the pulsed power team presented Aldermaston's director Peter Jones, a former chief warhead designer, with a highly classified Christmas card. The photograph showed the innards of a full-scale atomic warhead on the point of exploding.

Martin was never an easily manageable scientist. He would tell visitors his laboratory was out on the boundary of the sprawling Aldermaston campus: "as far as possible from the administrators". One of his bosses in the 1980s says: "The best way to manage Charlie was to let him get on with it." Another, more recently, that "Charlie had the fastest brain I ever came across".

Martin was appointed a Deputy Chief Scientific Officer on special merit in 1974. In 1977 the US Government awarded him its Defence Nuclear Agency Gold Medal: an award made only rarely to non-US citizens, of which he was specially proud. He was appointed CBE in 1989, accepting it as an honour for his team.

Martin was a Londoner who read Physics at Imperial College. He never married but lived in one room at Boundary Hall, Aldermaston, during the normal working week, and in London at weekends. When he began semi-retirement at 65 he settled in Bloomsbury, close to his favourite theatres, cinemas, restaurants and bookshops. But his wide circle of friends knew that Aldermaston took first place, until he became ill.

He was famous at Aldermaston for a gargantuan appetite. He would often eat two cafeteria dinners in the time others took to eat one. One of his principal recreations was dining with friends, but he never recovered his zest for it after an operation a year ago, for cancer of the oesophagus. He inspired great love and affection in countless friends, from his cleaner at Boundary Hall to Edward Teller, foremost US weapon designer, who called him his "scientific son".

Charlie Martin's careful husbandry of public monies - his "string-and- sealing-wax" approach to experimentation - was reflected in his personal life. Although generous to friends he had little interest in personal possessions, including clothes, which he tended to buy in bulk. He holidayed in the eastern Mediterranean - Greece, Turkey, Egypt - usually combining snorkelling with study of their archaeological treasures.

John Christopher (Charlie) Martin, nuclear weapon designer: born London 21 September 1926; Deputy Chief Scientific Officer, United Kingdom Atomic Energy Authority 1974-86; CBE 1989; died London 22 March 1999.