Abstract
The neutron backgrounds induced by supplementary
experimental materials can result in contaminations in rare event
search experiments. To address this, we present the neutron
background levels arising from ambient materials in the polyethylene
room of the China Jinping Underground Laboratory; particularly, we
compare simulated spectra with measured neutron spectra unfolded
using a genetic algorithm. The genetic algorithm optimizes the
continuity of the energy spectra and obtains a reasonable spectral
result. A good agreement between the unfolded and simulated spectra
is achieved. Moreover, estimated neutron background levels of
representative ambient materials such as polyethylene, aluminum, and
lead are obtained using an exposure time of 511.27 days via a 28
liter 0.5%-gadolinium-doped liquid scintillator detector. The
identification of rare neutron sources can aid in background
reduction in next-generation large-scale rare event experiments.
Neutron background measurement for rare event search experiments in the YangYang underground laboratory
