“…While this is a conservative practice, there is compelling evidence that the actual surface of copper calorimeters is not fully catalytic, owing to the rapid oxidation of copper upon exposure to plasma. Numerous studies have been dedicated to characterize the catalytic properties of copper and its surface oxides (CuO and Cu 2 O) [10,13,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37]. In a second step, hot wall measurements are performed on the TPS material sample in order to determine its catalytic property γ, for a known test condition determined through the rebuilding of cold-wall measurements.…”