Construction started in April 2007. The detector was completed in September 2010. Commissioning run was conducted between October 2010 and June 2012. Scientific data taking begun in November 2013. The detector is sometimes called XMASS-I, as it is planned to be superseded by an upgrade called XMASS-1.5 (a 5-ton detector) and eventually XMASS-II (24 ton detector).