Measurement of fast neutron background in the Gran Sasso underground laboratory using a geyser-concept bubble-chamber

Abstract A measurement of the fast neutron background in the Gran Sasso underground laboratory has been performed by the MOSCAB thermodynamic bubble chamber, a neutron detector which identifies fast neutrons passing through the metastable fluid by scattering ions. The result of this measurement confirms the results previously obtained using detectors based on totally different techniques, thus corroborating the previous results in terms of both integral intensity and spectral characteristics, at least in the energy region where the current measurement technique is sensitive.