Thermal neutron flux measurements in STAR experimental hall

We report on measurements of thermal neutron fluxes at different locations in the STAR experimental hall during pp $\sqrt s$ = 510 GeV Run 13 at RHIC. We compared these measurements with calculations based on \textsc{PYTHIA} as minimum bias events generator, the detailed GEANT3 simulation of the STAR detector and the experimental hall, and using GCALOR as neutron transport code. A good (within $\approx$ 30%) agreement was found at locations near ($\approx$1m) and very far ($\approx$10m) from the beam pipe. For intermediate locations ($\approx$ 5m) the simulation overestimates neutron flux by a factor of $\approx$3.