Comparison of tritium measurement techniques for a laser cleaned JET tile

Abstract

Over the last 7–8 years, two quantitative analyzing methods—accelerator mass spectrometry (AMS) and full combustion (FC) followed by scintillation detection have been applied for determining the tritium activity concentrations in JET divertor tiles. These methods have two main differences – the range of detection and the spatial resolution – and are thus complementary. However, these differences can also complicate the comparison of the two techniques for typical JET divertor samples. Therefore a cross comparison exercise for tritium measurements was performed between the two methods using specially produced identical standard samples. The cross comparison measurements were performed firstly on the identical standard samples and were extended then to selected samples from the JET divertor tile (laser treated and non-treated samples from tile 14ING3B exposed in 2001–2004). The results obtained by AMS and FC agreed within an error limit of 10% for the standard samples and of 18% for the JET divertor samples. The results of this comparison study provided also useful information concerning the efficiency of tritium removal from the plasma facing surface of the divertor tiles by means of laser ablation.