Shock tube event validation

A detonator which is configured to be connected to an end of a shock tube which, upon ignition, generates a shock tube event at the end, the detonator including at least a first sensor, a second sensor, a processor and a timer, and wherein the first sensor upon detecting a first characteristic associated with the shock tube event transmits a first signal at a time T0 to the processor and, at a time T1 which is at a predetermined time interval P1 before the time T0, the processor determines whether the second sensor had sensed a shock tube event, characterised in that the second sensor includes a fusible link and in that the shock tube event is validated if, at the time T0, the fusible link was integral and if, at a time T2, which is after the end of the first characteristic, the fusible link was in a fused state.