Abstract: Embodiments of the present invention provide a detector comprising at least one detector element, the at least one detector element comprising: a photodiode element operable to generate charge carriers, the detector being configured to generate a signal indicative of a cumulative amount of charge carriers generated by the photodiode element during the integration period; a reset switch element configured to couple the photodiode element to a reset potential; at least one charge storage reservoir; and at least one gain control switch element configured to couple at least one said at least one charge storage reservoir to the photodiode element, wherein the detector is configured to perform a reset operation in which the reset switch element and at least one said at least one gain control switch element are closed in order to couple at least one said at least one charge storage reservoir and the photodiode element to the reset potential, the detector being configured to open at least one gain control switch elem