Purdue University dedicated its tandem accelerator to accelerator mass spectrometry in 1989; external funding began in April 1990; and the first AMS measurements took place in early 1991. The internal upgrade of the accelerator, which included new acceleration tubes and a new charging system, took place from December 1993 through April 1994. The upgrade of the analyzing magnet to fast isotope switching took place November 1998 through February 1999. The upgrade of the injector magnet is taking place in February 2001.