Physical calibration of the LEND space-based neutron telescope: the sensitivity and the angular resolution

Results of physical calibrations of the LEND neutron telescope operating on board the NASA’s LRO lunar satellite since June 2009 are described. The main goal of the LEND telescope is to measure the epithermal neutron flux in polar areas of the lunar surface with a high (~10 km) resolution with the aim of determining the hydrogen distribution in the lunar regolith and detect the presence of water ice beds at the bottom of permanently shadowed lunar polar craters. The neutron detection efficiency and the effective area of the LEND detectors is experimentally estimated.