First results with the upgraded TLK tritium calorimeter IGC-V0.5

• We have upgraded a 12 years old tritium calorimeter.
• We have developed a new control and data acquisition software using LabView.
• The retuned PID control loops increased stability and accuracy.
• The automatic control algorithm can reduce measurement time and avoid possible operator errors.
• We compared calibration results made with the original and the upgraded system.

At Tritium Laboratory Karlsruhe (TLK) calorimetry has been used for almost 20 years as the main accountancy method for tritium inventory. An extensive work has been carried out in order to improve the existing calorimeters. This paper covers the efforts made for the upgrade of the IGC-V0.5 calorimeter. We replaced the hardware interface – including the obsolete PC – and developed a new control and data acquisition software. The new software applies a smart automatic process control during measurements, significantly reducing measurement time and possible user errors. The three PID control loops have been re-tuned using the standard closed loop Ziegler–Nichols procedure to find the optimal PID parameters. Five calibration runs have been performed between 0.5 μW and 1 W, and their results are being presented and discussed.