Liu, X. Chen, Q.S. Chen, W. Qin, B. Tang, K. JACoW Geneva, Switzerland 978-3-95450-192-2 10.18429/JACoW-IBIC2017-MOPCF03 English 81-84 MOPCF03 ion proton diagnostics beam-diagnostic cyclotron Contribution to a conference proceedings 2018 2018-03 https://doi.org/10.18429/JACoW-IBIC2017-MOPCF03 http://jacow.org/ibic2017/papers/mopcf03.pdf Proton therapy is now recognized as one of the most effective radiation therapy methods for cancers. A proton therapy facility with multiple gantry treatment rooms is under development in HUST (Huazhong University of Science and Technology), which is based on isochronous superconducting cyclotron scheme. The 250MeV/500nA proton beam will be extracted from a superconducting cyclotron and injected into the beam-line. Many beam diagnostic instruments are distributed throughout the beam line to measure the beam profile, position, current, loss, energy and energy spread. Some of them will send the beam information to the treatment control system (TCS) and serve as the safety interlock. This paper presents the considerations for the distribution of beam diagnostic instruments and shows the layout of beam diagnostics monitors in the beamline.