A FUNDAMENTAL STUDY IN NEUTRON RADIOGRAPHY

Journal Article · Tue Jan 01 04:00:00 EST 1963 · Proc. Japan Conf. Radioisotopes

OSTI ID:4681773

Kabayashi, M; Nakajima, K

A preliminary study on the fundamental aspects of use of neutron radiography for nondestructive inspection of materials was carried out. The yield of thermal neutrons was measured first by using a 20-mC Ra-- alpha --Be neutron source and a BF/sub 3/ counter, which showed the maximum yield of the thermal neutron flux at 6 to 7 cm thicKness of paraffin. The absorption curves determined for several materials such as iron, lead, and cadmium showed good agreement with those obtained by calculations uslng thermal cross sections, whereas the coefficient obtalned by water was much lower than what was expected. The radiography was tried by using a cyclotron in which the neutrons accelerated up to 3.5 Mev bombarded a berylliNoneum target. This resulted in the production of fast neutrons by the nuclear reaction Be/sup 9/ + H/sup 2/ yields n + B/sup 10/. These fast neutrons were moderated in a paraffin layer 8 cm thick, which permitted use of a thermal neutron flux of 7 x 10/sup 5/ n/cm/sup 2/ sec at 50 cm from the target. The use of an intensifying screen composed of double layers of ZnS scintillator and boric acid showed a remarkable blackening effect on the industrial x-ray film. However, without the intensifying screen or with a ZnS scintillator screen only, the blackening of the film was observed. It was due to the presence of an intense gamma-ray flux produced by the nuclesr reaction or the collision of the neutron. It was found that a film received about 0.5 to 1 roentgens of gamma radiation during an exposure for neutrons. In order to establish a simple and practical way of neutron radiography, the image transfer'' method was investigated by using a nuclear reactor. An indium plate, 0.35 mm thick, was irradiated for 10 minutes in a neutron flux of 10/sup 6/ n/cm/ sup 2/ sec of a thermal column, which produced a radioactivity of about 2 x 10/ sup 4/ dps/cm/sup 2/ by a nuclear reaction /sup 115/In(n, gamma )/sup 116m/In. An exp osure of 3 hours after the irradiation gave a good resolution on a developed x-ray film. (A.G.W.)

• Research Organization: Tokyo Metropolitan Isotope Center
• NSA Number: NSA-17-030147
• OSTI ID: 4681773
• Journal Information: Proc. Japan Conf. Radioisotopes, Journal Name: Proc. Japan Conf. Radioisotopes Vol. Vol: 5th, No. 3
• Country of Publication: Country unknown/Code not available
• Language: Japanese

Related Subjects

ABSORPTION
ALPHA PARTICLES
BERYLLIUM
BERYLLIUM 9
BERYLLIUM FLUORIDES
BORIC ACID
BORON 10
BORON OXIDES
CADMIUM
COUNTERS
CROSS SECTIONS
CYCLOTRONS
DEUTERON BEAMS
FILMS
GAMMA RADIATION
GENERAL AND MISCELLANEOUS
IMAGES
INDIUM
INDIUM 115
INDIUM 116
INSPECTION
INTERACTIONS
IRON
IRRADIATION
LAYERS
LEAD
MEASURED VALUES
MODERATORS
NEUTRON FLUX
NEUTRON SOURCES
NEUTRONS
NUCLEAR REACTIONS
PARAFFIN
PLATES
PRODUCTION
RADIOACTIVITY
RADIOGRAPHY
RADIUM
RESOLUTION
SCINTILLATIONS
TARGETS
THICKNESS
WATER
X RADIATION
ZINC SULFIDES