Recent DIII-D neutral beam calibration results

The fundamental parameters by which injected DIII-D neutral beam power is calculated have all been recently measured using waterflow calorimetry and target tile thermocouples. The measured neutralization efficiency is 66%, close to the modeled equilibrium value of 70% for a 75 kV deuterium beam. Waterflow calorimetry has proven to be a useful tool to measure the neutralization efficiency, contrary to earlier results. The beamline transmission efficiency has been measured for each beam independently, and averages about 78% among the beams. Finally, the drift duct reionization survival rate is 95%. By making use of the independence of preshot target tile temperature and duct reionization, interpretation of thermocouple data has yielded more accurate results.<
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