Photoneutron spectrum measured with a Bonner sphere spectrometer in planetary method mode

•The photoneutrons spectrum of a 15 MV LINAC was measured.•A Bonner sphere spectrometer with pairs of TLDs were used.•Measurements were carried out with the BSS in Planetary method mode.•Measured spectrum is compared with calculated spectrum.

The spectrum of photoneutrons produced by a 15 MV VARIAN iX linac working in Bremsstrahlung mode was measured a 100 cm from the IC located 5 cm-depth of a solid water phantom. The spectrum was measured with a Bonner spheres spectrometer with pairs of TLDs as thermal neutron detector. The measurements were carried out using the spectrometer in planetary method mode where a single shoot of the LINAC was required.