Operative results and utilizing status of cyclotrons

There are cyclotrons big (NIRS-930, manufactured by Thomson CSF and equipped in 1974) and small (HM-18, Sumitomo Heavy Industries, Ltd., 1994) in the NIRS Cyclotron Building, and their annual utilization is summarized. Total operated time of the big one amounts to 1,584 hr, in which 8-80 MeV proton was accelerated for 3-275 hr, 27 MeV hydrogen molecule (H₂⁺) for 115 hr, 30-35 MeV deuteron for 14-65 hr, 72-130* MeV C (*¹³C) for 4-74 hr, 60-100 MeV He for 22-23 hr, 96 MeV O for 43 hr and 120 MeV Ne for 31 hr. Its use included the adjustment of beam conditions (547 hr/1,584 hr: 34.5%) for following needs: manufacturing and studying of radiopharmaceuticals (27.9%) through production of ¹²⁴I, ⁷⁶Br, ¹⁸F, ⁶²Zn/⁶²Cu and ⁸⁹Zr; beam provision with pay (12.0%) by the use of 4 organizations mainly aiming at evaluation of the cosmic ray effect; physics studies (10.6%) such as measurement of gamma ray at the high energy neutron field, of double differential cross section of fragment production by nuclear spallation, etc.; development of the detector of particle beam (6.2%); and others like the examination of material injuries by the beam. The small cyclotron can accelerate either 18 MeV proton or 9 MeV deuteron, for which annual operated time was 1,682 or 9 hr, respectively. The former was used mainly (98.8%) for manufacturing ¹¹C-, ¹³N- or F¹⁸-radiopharmaceutical. Remaining times were spent for their maintenance. (T.T.)