Detonator sensing arrangement

An electronic detonator which includes an arrangement for sensing and validating the occurrence of a shock tube event, the arrangement including a support, a housing mounted to the support, a passage which extends through the housing, an inlet to the passage which is configured to be exposed to a wave front produced at an end of a shock tube, an outlet from the passage, and at least one fusible link at the outlet, which extends transversely to a longitudinal axis of the passage and wherein the passage between the inlet and the outlet is tapered to reduce the cross-sectional area dimension of the passage from the inlet to the outlet, so that a wave front from the shock tube event through the passage is concentrated at the outlet.