The use of a pulsed van de Graaff accelerator and time-of-flight techniques to reduce backgrounds in (α,γ) spectroscopy experiments

A pulsed beam of alpha particles from a 5.5 MV Van de Graaff accelerator has been used to study radiative capture reactions. Time-of-flight techniques are used to discriminate against neutrons produced when the beam interacts with collimator-target contaminants, as well as against beam independent background due to cosmic rays. With a beam pulse of less than 4 nsec (FWHM) duration and a repetition rate of 2 MHz, a portion of the 34S(α,γ)35Ar excitation function was examined near Eα=3.6 MeV and the background found to be an approximate factor of 15 below that of the effective dc excitation function. In addition it is demonstrated that an angular distribution taken on resonance by this method requires substantially less background subtraction. The method has also been successfully applied to radiative capture studies in which the incident beam energy is above the neutron threshold for the target nuclei

Duke Scholars

Author Ronald J. Jaszczak Radiology