Status of Tsukuba University tandem accelerator center

Tandem Accelerator Center of Tsukuba University was established on 1974. The 12UD pelletron tandem accelerator started its operation on 1976. In 1999, the operation times of the accelerator and beam use times were 2905 and 2316 hours, respectively. The new electrostatic quadra-pole lens was installed on March 1999. On July 1999, troubles happened in corona needles under 11 MV conditioning. The 25 years old SF6 compressor was to meet regular overhauling. There were three types of ion sources; those were 1) sputter ion source for hydrogen and deuterium, 2) polarized ion source and 3) AMS (Accelerator Mass Spectroscopy) ion source. The operation time of sputter ion source took up 34% of total operation time. The operation time of the AMS ion source was approximately 6%. The time for experiments on nuclear physics took up 60%. However, the experiments on material physics using the AMS ion source were increasing. Developments of 129I measurement are scheduled on 2000. The 20% of the total operation time was dedicated to on terrestrial science as the higher priority research. There was a use for bachelor students in the summer school. The 1 MV tandetron started its operation on the fiscal year of 1999. We had two type of ion source; those were 1) sputter ion source and 2) duo-plasmatron ion source for He acceleration. There are 5 beam lines, in which RBS (Rutherford Backscattering Spectroscopy) and PIXE (Photon-Induced X-ray Emission) had been commissioned. The beam-line for micro-PIXE and others are under construction. The beam operation times were 225 hours in 1999, due to many troubles in duo-plasmatron cooling system and so on. On the other hand, many users are expecting experiments on crystal physics using He beams. (Y. Tanaka)