Data report: testing and deployment of the new APC3 tool to determine in situ temperatures while piston coring

During Integrated Ocean Drilling Program Expedition 311, the third-generation advanced piston corer temperature (APCT-3) tool, a new downhole tool to determine in situ formation temperatures while piston coring, was successfully tested and deployed for the first time. Its development was partly driven by the need to replace the advanced piston corer temperature tools, which were lost or damaged during many successful deployments over the last 15 y. Additionally, many important scientific problems require instruments having greater stability, accuracy, measurement frequency, and robustness than were available in the past. During all nine deployments during Expedition 311, the APCT-3 tool proved to be robust, reliable, and user-friendly regarding its mechanics, electronics, and operation software. In addition, the test deployments also provided temperature data that were important for achieving expedition objectives. Moreover, it was demonstrated that the APCT-3 tool is capable of measuring temperatures with a resolution and absolute accuracy (depending on careful calibration) of ~1 mK at a sampling interval of 1 s, an improvement of about one order of magnitude compared to earlier instrumentation.