The NPL Mark II Watt Balance: Final measurements at NPL

Following the measurements made in the first half of 2008 and damage from a lightning strike in July 2008, final modifications and repairs to the NPL Mark II Watt Balance were completed in November 2008. The apparatus was realigned and measurements made from December 2008 to its shutdown in June 2009. A possible source of significant systematic error was discovered in June 2009 and initial tests were made to determine the magnitude of the effect. The apparatus has been transferred to NRC Canada and was dismantled and dispatched in the summer of 2009. It will be rebuilt in 2010.