Decomposition of prompt gamma-ray spectra including the Doppler-broadened peak for boron determination

In prompt γ-ray measurements following slow-neutron capture, the Doppler-broadened 478 keV peak resulting from capture in boron was deliberately overlapped with prompt γ-rays of similar energies resulting from capture in sodium, cobalt, and nickel. A peak decomposition method was developed in which the broadened line shape was represented by an integral of the Gaussian function and the spectrum in the 455–490 keV region was decomposed into a broad peak and interfering normal peaks by using a nonlinear least-squares procedure. The accuracy and detection limits of the current method for boron determination were confirmed by comparing the analytical results with those obtained by the reference line method and with boron amounts known during sample preparation by direct weighing and aliquoting.