Composite detectors as a beneficial tool for dose measurements of secondary radiation in Boron Neutron Capture Therapy

A concept for studying the effects of secondary radiation in boron neutron capture therapy based on the application of multilayer composite scintillators was proposed in this work. Such composite scintillators can be used for simultaneous measurement of the dose of various types of ionizing radiation, including 7Li ions, α-particles and γ-rays. For this purpose, three types of composite detectors based on the single crystalline films and single crystals of Y3Al5O12 and Lu3Al5O12 garnets, doped with Ce3+, Pr3+ and Sc3+ ions, were produced using the liquid phase epitaxy growth method. The scintillation reader for in-situ dose measurement of different radiation components at BNCT was constructed based on the developed types of composite detectors. The possibility of recording various radiation components was demonstrated using: 1) the differences in the pulse height spectra and scintillation decay kinetics of various parts of composite detectors under excitation by α-particles of 239Pu source; 2) the difference in the radioluminescence spectra of films and crystal scintillators in composite detectors under excitation by γ-rays of 192Ir (392 keV) source. The obtained results were discussed for choice of the best registration methods and types of composite detectors for direct dose measurements of secondary radiation under excitation with thermal neutrons.