MEASUREMENT OF THE THERMAL NEUTRON DIFFUSION PARAMETERS IN DIPHENYL AND MONOISOPROPYLBIPHENYL (MIPB) BY PULSED NEUTRON METHODS

Journal Article · Tue Oct 01 00:00:00 EDT 1963 · J. Nucl. Energy, Pt. A ; B

DOI:https://doi.org/10.1016/0368-3230(63)90121-6· OSTI ID:4155712

Blackshaw, G L; Waltner, A W

The diffusion parameters in diphenyl (C/sub 12/H/sub 10/) at 77 deg C and MIPB (C/sub 15/H/sub 16/) at 30 deg C were determined using the pulsed neutron source technique. A 1-Mev Van de Graaff accelerator was used as the pulsed source of fast neutrons utilizing the Be/sup 9/(d,n)B/sup 10/ reaction. The decay of the thermal neutron leakage from a finite cyrindrical geometry was measured using a 26-channel time analyzer. By measuring the thermal neutron decay constant, lambda , as a function of buckling, B/sup 2/, a least squares fit of the data to the equation lambda = lambda /sub O/ + D/sub o/B/sup 2/- CB/ sup 4/ yielded values of D/sub O/, the d iffusion constant, and C, the diffusion cooling coefficient. The infinite medium decay constant, lambda /sub O/, was calculated from known cross-section data. For diphenyl measurements in the buckling range from 0.0816 to 0.2811 cm/sup -2/, the diffusion parameter values obtained were D/sub O/ = 5.437 plus or minus 0.117 x 10/sup 4/ sup -1/. The results obtained for MIPB in the buckiing range from 0.0945 to 0.2952 cm/sup -2/ were D/sub O/ = 3.780 plus or minus 0.033, 10/sup 4/ cm/sup 2/-sec/sup 1/ and C = 1.25 plus or minus 1.43 x 10/sup 3/ cm/sup 4/-sec/sup -1/. The values of the transport mean free path, lambda /sub tr/, and diffusion length, L, derived from these results were found to be less than those values pre dicted by current theoretical models. A preliminary investigation of lambda /sub tr/ in MIPB as a function of temperature showed a non-linear behavior of the transport mean free path with temperature. (auth)

• Research Organization: North Carolina State Coll., Raleigh
• NSA Number: NSA-18-000989
• OSTI ID: 4155712
• Journal Information: J. Nucl. Energy, Pt. A ; B, Journal Name: J. Nucl. Energy, Pt. A ; B Vol. Vol: 17
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

BORON 10
BUCKLING
CONFIGURATION
COOLING
CROSS SECTIONS
CYLINDERS
DECAY
DEUTERON BEAMS
DIFFUSION
EQUATIONS
FAST NEUTRONS
MEAN FREE PATH
MEASURED VALUES
NEUTRON FLUX
NEUTRON SOURCES
NUCLEAR REACTIONS
NUMERICALS
PHENYL RADICALS
PHYSICS
PULSE ANALYZERS
PULSES
TEMPERATURE
THERMAL NEUTRONS
TRANSPORT THEORY
VAN DE GRAAFF ACCELERATORS