Experimental determination of the buckling for unusual geometrical shapes using paraffin

The buckling constant for neutron moderators in the shape of an elliptic cylinder, hemisphere, and"piggy-back" cylinder has been determined by experimental measurements using paraffin as a moderator. The pulsed neutron sources technique was used throughout the work; a fast neutron burst of short duration was injected into regular paraffin shapes (cylinders with diameter and height ratio equal approximately to one). An empirical curve of decay constant of the neutron population versus the buckling was obtained. The measured decay constant, λ, was fitted by the method of least square to a parabola in B² of the form: λ=Σ_av+ B²D - CB⁴ where λ= the decay constant B² = the buckling constant Σ_a = the macroscopic absorption cross section v = the neutron velocity D = diffusion coefficient C = diffusion cooling coefficient The resulting values of the diffusion parameters are: Σ_a v = 4858 ± 162 sec⁻¹ D = 25911 ± 202 sec⁻¹ cm² C = 1186 ± 2558 sec⁻¹ cm⁴ By measuring the decay constant, the buckling of the moderators with irregular shapes were determined from the above parameters. The result was in general accord with the theoretical approximations for such shapes.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Physics

Department dc:contributor.department

Physics

Grantor dc:publisher

Virginia Polytechnic Institute

Year dc:date.issued

1963

Author dc:creator

• Hwu, Yeu-Pyng

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10919/74554

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/74554