(19)

(11)

EP 0 105 891 A1

(12)

(43) Date of publication: 25.04.1984 Bulletin 1984/17 (21) Application number: 83901216.0 (22) Date of filing: 19.04.1983

(51) International Patent Classification (IPC):  G01N 31/ 12( . ) G01N 33/ 28( . ) (86) International application number: PCT/GB1983/000114 (87) International publication number: WO 1983/003676 (27.10.1983 Gazette 1983/25)

(84) Designated Contracting States: DE FR GB (30) Priority: 20.04.1982 GB 19820011358 (71) Applicant: The Secretary of State for Energy in Her Britannic Majesty's Government of the United Kingdom of Great Britain London SW1P 4QJ (GB)	(72) Inventor: BATHER, John Maxwell Prestbury Cheshire SK10 4BU (GB) (74) Representative: Beckham, Robert William, et al  Defence Research Agency Intellectual Property Department DRA Farnborough Farnborough, Hants. GU14 6TD Farnborough, Hants. GU14 6TD (GB)