My previous response did not get through, so here goes - I have not seen any reference to the field intensity of the x-ray. Although I have no experience with X-ray techniques for excessive Sn/Pn migration, I would have to be absolutely convinced from an independent source - publication, standard, research paper, etc., that xray techniques are allowed. Depending upon the level of field intensity, flooding semiconductor material with x-rays can: 1. Knock electrons loose create current flow and voltage potentials on an unconnected board. 2. Introduce interstitial defects in semiconductor material. Doug McKean ADC Video Systems [log in to unmask]