Speaker
Description
The $^{197}$Au($\gamma$,n)$^{196}$Au reaction is commonly used as a reference process to measure the gamma beam intensity in photonuclear reaction experiments. However, at energies higher than 14.7 MeV, the cross-section values of the $^{197}$Au($\gamma$,n)$^{196}$Au reaction available in the literature (both from experiments and theory) exhibit conflicting values. Thus, we performed a new measurement of the $^{197}$Au($\gamma$,n)$^{196}$Au reaction cross section at the HI$\gamma$S facility using the activation method. A beam of nearly-monochromatic photons at various energies (10 MeV-20 MeV) was used to activate several gold foils. After irradiation, the number of gamma decays of 196Au (at energies of 333 keV and 356 keV) was measured for each gold foil using a HPGe detector. The intensity of the beam was measured using a dual fission chamber and a thin plastic scintillator. The combined use of these
beam diagnostic systems and the measure of the disintegrations of $^{196}$Au, provided a new measurements of the $^{197}$Au($\gamma$,n)$^{196}$Au cross-section reducing the experimental errors with respect to the previous experiments. This result is important to improve the measurement of the gamma-beam intensity for the study of ($\gamma$,$\alpha$) and ($\gamma$,p) reactions of interest for the astrophysics.
In this presentation experimental procedure and preliminary results will be shown.
