title: A neutron track etch detector for electron linear accelerators in radiotherapy.
abstract: BACKGROUND
  Electron linear accelerators in medical radiotherapy have replaced cobalt and caesium sources of radiation. However, medical accelerators with photon energies over 10 MeV generate undesired fast neutron contamination in a therapeutic X-ray photon beam. Photons with energies above 10 MeV can interact with the atomic nucleus of a high-Z material, of which the target and the head of an accelerator consist, and lead to the neutron ejection.
  
  
  CONCLUSIONS
  Our neutron dosimeter, composed of the LR-115 track etch detector and boron foil BN-1 converter, was calibrated on thermal neutrons generated in the nuclear reactor of the Josef Stefan Institute (Slovenia), and applied to dosimetry of undesirable neutrons in photon radiotherapy by the linear accelerator 15 MV Siemens Mevatron. Having considered a high dependence of a cross-section between neutron and boron on neutron energy, and broad neutron spectrum in a photon beam, as well as outside the entrance door to maze of the Mevatron, we developed a method for determining the effective neutron detector response. A neutron dose rate in the photon beam was measured to be 1.96 Sv/h. Outside the Mevatron room the neutron dose rate was 0.62 μSv/h. PACS: 87.52. Ga; 87.53.St; 29.40.Wk.
authors.affiliation: Department of Physics, University of Osijek; Osijek, Croatia.
authors.forename: Branko
authors.initials: B
authors.lastname: Vukovic
authors.forename: Dario
authors.initials: D
authors.lastname: Faj
authors.forename: Marina
authors.initials: M
authors.lastname: Poje
authors.forename: Maja
authors.initials: M
authors.lastname: Varga
authors.forename: Vanja
authors.initials: V
authors.lastname: Radolic
authors.forename: Igor
authors.initials: I
authors.lastname: Miklavcic
authors.forename: Ana
authors.initials: A
authors.lastname: Ivkovic
authors.forename: Josip
authors.initials: J
authors.lastname: Planinic