FRAGMENT KINETIC ENERGY AND MASS DISTRIBUTION FOR FISSION OF URANIUM BOMBARDED BY 55.3 Mev PROTONS

Journal Article · Thu Aug 01 04:00:00 EDT 1963 · Genshikaku Kenkyu (Japan)

OSTI ID:4074919

Shirato, S; Seki, M

Kinetic energy and mass distributions of fragments in the 55.3-Mev proton-induced fission of U/sup 235/ and U/sup 238/ were measured using a back-to- back arrangement of surface barrier type semiconductor detectors and a pulse division circuit. The detection system was tested by measuring fragment distributions for the thermal-neutron-induced fission of U/sup 235/. The pulse height defect of the detectors used was determined by comparing the single fragment energy distribution with the time-of-flight data of Milton and Fraser. When corrected approximately for the defect, the measured mass distribution for the thermal-neutron fission of U/sup 235/ agreed well with the radiochemical data. In the case of 55.3-Mev proton-induced fission, corrections must be made for the projectile momentum and the neutron emission. A correction method for the neutron emission is discussed. A fair agreement is found between the corrected mass distribution for the 55.3-Mev proton fission of U/sup 238/ and the radiochemical data of Stevenson et al. at the proton energies of 32 and 70 Mev. The most probable values of total fragment kinetic energy in the 55.3-Mev proton fissions of U/sup 235/ and U/sup 238/ were 150 plus or minus 5.4 Mev and 152 plus or minus 5.4 Mev, respectively. Their full widths at half maximum were both comparable with the one for the thermal-neutron fission. A small but definite difference was observed between the mass distributions obtained at 90 deg for U/sup 235/ and U/sup 238/ fissions; the peak-to-valley ratio in U/sup 238/ was slightly larger than that of U/sup 238/. The mass distributions for 55.3-Mev proton fission of U/sup 238/ measured at 90 deg and 143 deg in the laboratory system showed that the anisotropy of symmetric fission fragments was somewhat larger than that of asymmetric fission. This fact is not inconsistent with the Meadow's result which was interpreted by Malpern as caused by slow cascade nucleons. (auth)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-18-009334
• OSTI ID: 4074919
• Journal Information: Genshikaku Kenkyu (Japan), Journal Name: Genshikaku Kenkyu (Japan) Vol. Vol: 8; ISSN GEKEA
• Country of Publication: Country unknown/Code not available
• Language: Japanese

Related Subjects

ANGULAR DISTRIBUTION
ANISOTROPY
CIRCUITS
CRYSTAL COUNTERS
DETECTION
DISTRIBUTION
EMISSION
ENERGY RANGE
FISSION
FISSION PRODUCTS
MASS
MEASURED VALUES
MEV RANGE
MOMENTUM
NEUTRONS
NUCLEONS
PHYSICS
PROTON BEAMS
PULSES
SCATTERING
SEMICONDUCTORS
THERMAL NEUTRONS
URANIUM 235
URANIUM 238
VELOCITY