Status of the JAERI accelerator

The installation and test works of a 20 MV heavy ion tandem accelerator has been continued since July, 1978, at Tokai Research Establishment of Japan Atomic Energy Research Institute. It is a Model 20 UR Pelletron folded tandem accelerator manufactured by National Electrostatic Corp. in Wisconsin, USA. The installation of all the equipments of the system was completed, and all the specifications of ion beam performance were satisfied at the terminal voltage below 18 MV by June, 1982. The accelerator was able to run sufficiently stably in the case of the heavy ion experiment with both continuous and pulsed beams. The contract was terminated in August, 1982, though the achievement of 20 MV was left for the future, and the scheduled running of the accelerator for experiment started on September 1, 1982. The JAERI tandem accelerator has operated reliably during the past 31 months, and the rotating shafts have accumulated 8790 operation hours. The accelerator was conditioned so as to run at 19 MV. 31 elements ranging from hydrogen to bismuth have been successfully accelerated. The frequent start-up and cooling of the ion sources resulted in the malfunction. An extension to the injector was constructed. (Kako, I.)