TY - JOUR A1 - Maierhofer, Christiane A1 - Röllig, Mathias A1 - Steinfurth, Henrik A1 - Ziegler, Mathias A1 - Kreutzbruck, Marc A1 - Scheuerlein, C. A1 - Heck, S. T1 - Non-destructive testing of Cu solder connections using active thermography JF - NDT & E international N2 - Impulse and lock-in thermography have been applied to detect delaminations of prototype solder joints, similar to those to be produced between Cu shunts and Cu busbar stabilisers at the Large Hadron Collider (LHC) at CERN. Two infrared cameras with different detector materials and with different spectral ranges and two excitation techniques have been tested and compared for their ability to detect delaminations behind 2 and 3 mm thick Cu shunts. We have analyzed the signal to noise ratio (SNR) for each detected defect and are able to detect defects down to a nominal edge length of 4 mm behind 2 mm thick Cu shunts by using fast impulse thermography and a camera with a microbolometer array. For the 3 mm thick Cu shunt, on the other hand, the nominal 4 mm defect is only visible in the lock-in thermography phase images and the highest SNR has been achieved with a cooled InSb-based camera. In addition, numerical simulations show the influence of the minimum detectable defect size on the shunt thickness and that the developed on-site testing technique is sufficient to find all defects that are detectable theoretically. KW - Active thermography KW - Solder joint KW - Copper KW - FFT KW - Signal-to-noise-ratio PY - 2012 DO - https://doi.org/10.1016/j.ndteint.2012.07.010 SN - 0963-8695 VL - 52 SP - 103 EP - 111 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-27575 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -