ASYMPTOTIC NEUTRON SPECTRA IN MULTIPLYING MEDIA

Technical Report · Tue Jan 01 04:00:00 EST 1963

OSTI ID:4667709

Slovacek, R E; Fullwood, R R; Gaerttner, E R; Bach, D R

Asymptotic low-energy neutron spectra were measured for two multiplying systems. The reentrant hole spectrum (scalar flux) and the surface leakage spectrum were obtained for both assemblies using the pulsed-source chopper technique at a linear accelerator. By increasing the time between the linear accelerator pulse and the chopper opening, the spectrum was observed to approach an asymptotic distribution after 50 to 100 mu sec, depending on the spectrum source and the experimental arrangement. The first multiplying medium consists of an array of fuel strips in water with a multiplication of about 4. To reduce the uncertainties in the calculation due to system boundaries and the self- shielding factor, a homogeneous medium was constructed of fuel blocks. This paraffin-fuel dispersion was stacked and surrounded by a Cd-lined B/sub 4/C shield box. No significant multiplication was measured for this thin sssembly. The agreement between calculated and measured scalar spectra is good. (M.C.G.)

• Research Organization: Rensselaer Polytechnic Inst., Troy, N.Y.; Knolls Atomic Power Lab., Schenectady, N.Y.
• NSA Number: NSA-17-032971
• OSTI ID: 4667709
• Report Number(s): CONF-11-6
• Country of Publication: United States
• Language: English

Related Subjects

BORON CARBIDES
CADMIUM
CHOPPERS
CURRENTS
CYLINDERS
DISPERSIONS
DISTRIBUTION
ELECTRIC CONDUCTIVITY
ENERGY
FUELS
INTERACTIONS
LINEAR ACCELERATORS
MAGNETIC FIELDS
MEASURED VALUES
NEUTRON SOURCES
NEUTRONS
NUMERICALS
PARAFFIN
PHYSICS
PULSE GENERATORS
SHIELDING
SPECTRA
SURFACES
VECTORS
WATER