A mobile helium-jet transport system for on-line spectroscopy of short-range spallation products

Abstract A mobile helium-jet system has been set up, capable of transporting short-range spallation products (range in ThF 4 ⩽ 66 μ g/ cm 2 ) in a closed loop helium circuit. This system was used for the transport of spallation products produced by 600 MeV protons from a 232 Th and a 241 Am target in the extracted beam of the CERN Synchrocyclotron (SC). The activity was transported through a 61 m long capillary to a low-background area, where it was collected in a vacuum chamber on a moving tape system. Alpha- and gamma-ray singles spectra, alpha-gamma coincidence spectra, as well as fission spectra could be investigated.