The BN Samples as Targets for Studies of Nuclear Reactions on Nitrogen: ¹⁴N(p,d)¹³N at Proton Energies Used in Hadrontherapy

The BN samples, prepared in UNIPRESS by sintering BN powder at 1000 degrees C under 7.7 GPa pressure, or available commercially from Saint-Gobain, were successfully used as nuclear targets irradiated simultaneously with proton beam of initial energy equal to 58 MeV. The reaction N-14(p,d)N-13 was studied through the measurement of beta(+) decay of N-13, leading to the emission of two 511 keV annihilation gamma-quanta measured in LaBr3:Ce scintillation detectors. The N-13 nucleus cannot be formed with proton on any boron isotope (A=10 or 11). A stack of BN targets was simultaneously irradiated, so the relative beam intensity was stable. Decay spectroscopy of 511 keV line (single and coincidence) was applied, allowing to disentangle beta(+) decays of N-13 and C-11 (produced in N-14(p,alpha) and B-11(p,n) reactions) with relative intensities determined with 3% precision.