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 s = 510 GeV Run 13 at RHIC. We compared these measurements with calculations based on 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 ≈ 30%) agreement was found at locations near (≈1m) and very far (≈10m) from the beam pipe. For intermediate locations ( ≈ 5m) the simulation overestimates neutron flux by a factor of ≈3