Affiliations: Bechtel Marine Propulsion Corporation, Schenectady,
NY, USA | St. Peter's Hospital, South Manning Boulevard, Albany,
NY, USA
Note: [] Corresponding author: Robert C. Block, Department of Mechanical,
Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, 110
8th Street, Troy, NY 12180, USA. Tel.: +1 518 276 6404; Fax: +1 518
2764 007; E-mail: blockr@rpi.edu
Abstract: The interpretation of neutron cross section experiments depends upon
an in-depth knowledge of the physical characteristics of the target sample. An
x-ray image of an encapsulated metallic Eu sample used in a neutron cross
section measurement showed a very non-uniform thickness as well as holes in the
sample. In light of this problem it was found necessary to determine the
thickness distribution in four thin metallic Eu samples without disturbing the
encapsulation (and exposing the Eu to air). All four Eu samples were
subsequently x-rayed along with a Sm step wedge. The gray levels in the Eu
images were then compared to the Sm gray levels and, taking into account
differences in the x-ray absorption and density of Eu and Sm, the sample
thickness distributions were obtained for each Eu sample. This work demonstrates that a step wedge can be used to calibrate x-ray images to a
thickness scale, and allows the thickness variation of the samples to be
represented in a simple probability table for incorporation into the analysis
of neutron experiments.
