Application of lithium fluoride dosemeters (TLD-600) in the photoneutron field mapping of a medical linear accelerator

Abstract

A 23 cm diameter polyethylene Bonner sphere containing a central set of three TLD-600 dosemeters (6LiF:Ti,Mg) chips was exposed to the primary photon beam as well as scattered photoneutron-gamma mixed radiation field near a cylindrical water phantom, irradiated with a 15 MV photon beam of field size 10 × 10 cm2 at the isocentre of a Siemens MD2 medical linear accelerator. The TL glow curves were deconvoluted using the first order TL kinetics model. The neutron and photon calibration factors were calculated from the deconvoluted glow peak areas to estimate separately the photon and photoneutron doses in the vicinity of the phantom. At the isocentre a neutron dose of 3.97 μGy ± 10% was measure..