Miyawaki, N. Fukuda, M. Ishioka, N.S. Kashiwagi, H. Kurashima, S. Watanabe, S. JACoW Publishing Geneva, Switzerland 2673-5482 978-3-95450-212-7 10.18429/JACoW-CYCLOTRONS2022-MOPO013 English 83-86 cyclotron controls experiment target extraction Contribution to a conference proceedings 2023 2023-10 https://doi.org/10.18429/JACoW-CYCLOTRONS2022-MOPO013 https://jacow.org/cyclotrons2022/papers/mopo013.pdf The TIARA AVF cyclotron provides a He beam for production of At-211 as one of many beam applications. The production rate of At-211 increases with the energy of the He beam, but contamination of Po-210 produced by radioactive decay of At-210, which is generated by the energy of above 29 MeV, must be prevented for medical applications. Therefore, the energy of the He beam must be precisely measured and controlled. A time-of-flight beam energy monitor in the straight beamline from the cyclotron was installed to measure the beam energy in real time. The beam energy was arbitrarily controlled within a range of about 1% by adjusting the cyclotron magnetic field and accelerating voltage, which are the possible causes of the beam energy change. Using this control, we investigated the rate of formation of At-211 and At-210 as the beam energy was varied. As a result, we confirmed the energy generating At-210 and both production rates increased with the energy of the He beam.