Recommissioning the KA2 Fast Ion Loss Detector on JET in Preparation for DT-Campaign*

The KA2 Faraday cup fast ion lost detector has been recommissioned on JET in preparation for the upcoming DT-campaign. The detector consists of five particle collector receptacles spaced poloidally along a fixed toroidal location from the midplane to $\sim$0.7 m below. Each receptacle contains three radially displaced apertures which consist of a stack of alternating current collecting foils and insulating material. The detector provides 15\% incident particle energy resolution from $\sim$0.5-7 MeV with limited pitch discrimination, allowing for the measurement of lost energetic ions from ICRH, NBI heating, and alpha particle production. Initial results and measurements are presented from JET’s 2019 deuterium campaign in preparation for recording alpha losses during the upcoming DT-campaign. New cabling and signal filtering have been implemented on the detectors to reduce ambient plasma pickup and electrical noise for an improved signal-to noise ratio. Emphasis has been placed on assessing the systems performance to study Alf\'{e}n mode resonant transport of energetic ions which is particularly detrimental to the confinement of the ion population.