Epithermal neutron beam dosimetry with thermoluminescence dosemeters for boron neutron capture therapy

The characteristics of thermoluminescence (TL) dosemeters were investigated for the determination of dose components in tissue substitute phantoms irradiated with an epithermal neutron beam for boron neutron capture therapy (BNCT). New two-layer TL detectors of a Dosimeter Niewiadomski were tested for neutron and gamma detection: MTS-Ns with a thin active LiF:Mg,Ti layer for reduced self-shielding of thermal neutrons and MCP-7s ((LiF)-Li-7:Mg,Cu,P) with low sensitivity for neutrons compared with gamma radiation. For comparison the conventional TLD-100 and TLD-700 detectors of Harshaw were used. MCP-7s dosemeters were found to be less sensitive for thermal neutrons and therefore better than TLD-700. However, the thermal neutron sensitivity of MCP-7s dosemeters is relatively high, e.g. the correction factor for the excess TL signal above the gamma signal is similar to 0.5 at the depth of the thermal neutron fluence maximum. MTS-Ns TL dosemeters were found capable of measuring the relative neutron fluence and to be a useful addition to the activation foils in BNCT neutron dosimetry.