Jennifer L. Erchinger, John L. Orrell, Craig E. Aalseth, Bruce E. Bernacki, Matthew Douglas, Erin C. Finn, Erin S. Fuller, Martin E. Keillor, Shannon M. Morley, Crystal A. Mullen, Mark E. Panisko, Sarah M. Shaff, Glen A. Warren, Michael E. Wright,
"Development of an Ultra-Low Background Liquid Scintillation Counter for Trace Level Analysis,"
INMM 56th Annual Meeting, Indian Wells, California, 12-16 July 2015.
Low-level liquid scintillation counting (LSC) has been
established as one of the radiation detection techniques useful in
elucidating environmental processes and environmental monitoring
around nuclear facilities. The Ultra-Low Background Liquid
Scintillation Counter (ULBLSC) under construction in the Shallow
Underground Laboratory at Pacific Northwest National Laboratory
aims to further reduce the MDAs and required sample processing as
an ultra-trace level detection system. Through layers of passive
shielding in conjunction with an active veto and 30 meters water
equivalent overburden, the background reduction is expected to be
10 to 100 times below current lowbackground liquid scintillation
systems. Simulations have shown an expected background of around 14
counts per day. A novel approach to the light guide will use a
coated hollow light guide cut into the inner copper shielding.
Demonstration LSC measurements will show lowenergy detection,
spectral deconvolution, and alpha/beta discrimination capabilities,
from trials with standards of tritium, strontium-90, and
actinium-227, respectively. An overview of the system design and
expected demonstration measurements will emphasize the potential
applications of the ULB-LSC in environmental monitoring for treaty
verification, reach-back sample analysis, and facility