Gamma background is one of the main factors limiting the current VESUVIO capabilities. We aim at a characterisation of the time of flight dependence of the gamma background. This will be complemented by investigation of possible optimisation routes for the enhancement of the signal/background ratio and suppression of the sample-dependent gamma background. The proposed measurements will make use of a high resolution Ge detector with biparametric time of flight (in the range 20 us <tof< 15000 us) and gamma energy acquisition (10 keV<Eg<10 MeV). This proposal is set within the groups research programme on gamma background characterisation of ISIS beam lines in the framework of the CNR-STFC agreement.