Neutron spectrometry and dosimetry around 15 MV linac

Neutron spectra were measured at different locations around the couch and in the maze of a Varian Clinac 2100 linac for 15 MV X-rays. A slab of PMMA, Al or Pb was also positioned near a measurement point. The Bonner sphere spectrometry using paired thermoluminescence dosemeters, TLD-600 and -700, was used to measure the neutron spectra. Eight polyethylene spheres of diameters between 3 and 10 inches were employed. The unfolding of neutron spectrum was performed with the MAXED package. Using measured neutron spectra, the average neutron energy, absorbed dose, ambient dose equivalent, and effective dose were determined.