A Mirror World? Detector Background Measurements for a Mirror Neutron Regeneration Experiment*

There may exist a hidden mirror gauge sector with a complete copy of our normal gauge sector, standard model matter. This so-called mirror world would interact only weakly through the gravitational force, making it a candidate for dark matter, and may allow neutrons to oscillate. An experiment to search for neutron oscillations will take place at Oak Ridge National Laboratory’s High Flux Isotope Reactor (HFIR) using the General Purpose-Small Angle Neutron Scattering (GP-SANS) instrument and its low background Linear Position Sensitive Detectors (LPSD). We used a separate LPSD to characterize the sources of neutron backgrounds in the vicinity to determine the necessary shielding requirements for the GP-SANS detectors from backgrounds from cosmogenic sources or other instruments.  We will present results of the detector characterization, comparison to the GP-SANS detector performance, and background studies at GP-SANS.