Paper | Title | Page |
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WEPC015 | Tuning Methods for HIMAC Multiple-energy Operation | 2037 |
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Beam stability of multiple-energy operation at HIMAC synchrotron was improved for the fast raster-scanning irradiation. In order to improve the transverse stability, the working point of the betatron tune was investigated during one operation cycle. The signals were collected from the beam position monitor using a fast data-acquisition unit. The temporal evolution of the horizontal and vertical betatron tune was evaluated by using the short time Fourier transform. Analyzed results showed that variation of the betatron tune in the acceleration interval passed through the 3rd-order coupling resonance line, and it caused undesirable emittance growth. In order to keep the working point within the desirable operating region, the current pattern of the power supplies for the quadrupole magnets was corrected by using the variation of the betatron tune. The experimental results showed that the working point could be successfully stabilized, and the undesirable beam losses could be reduced during the acceleration interval. | ||
THPS071 | The HIMAC Beam-intensity Control System for Heavy-ion Scanning | 3592 |
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Raster scanning irradiation has been carried out at a HIMAC new treatment facility in NIRS. In order to reduce the difference between prescribed and delivered dose distribution, the accurate beam-intensity control with a low ripple and the fast beam-on/off switching are strongly required. For this purpose, we have developed a new beam-intensity control system using the RF-knockout slow extraction. To keep the beam rate constant, this system controls the transverse RF voltage with the feedback proportional-integral control. In addition, the beam-on/off response was improved by the fast quadrupole magnets and the implementation of the transverse beam preheating method. As a result of the system commissioning, it was verified that this system can modulate the beam-intensity with a low ripple and switch the beam-on/off with quick responses. We will report the result in detail. | ||
THPS072 | Commissioning of NIRS Fast Scanning System for Heavy-ion Therapy | 3595 |
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The commissioning of NIRS fast scanning system was started in September 2010, when the first beam was successfully delivered from the HIMAC synchrotron to the new treatment room. After the fine tuning of the new transport line, the commissioning of the scanning system was carried out as following steps; 1) verification of the beam size, position and intensity stability; 2) verification of beam scanning performance and calibration; 3) verification of beam monitor performance; 4) dose measurement of pencil beams for the beam parameterization in the treatment planning system; and 5) verification of 3D dose conformation. As a result of the commissioning, we verified that the new scanning delivery system can produce an accurate 3D dose distribution for the target volume in combination with the planning software. We will report the commissioning results and the performance of the scanning system. | ||
THPS076 | Sub-mm Therapeutic Carbon-Ion Irradiation Port in Gunma University | 3607 |
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Funding: This Study was done by Grant-in-Aid for Scientific Research (KAKENHI). One of advantage of particle therapy is concentration of irradiation dose. In April 2011, we developed "in-body-focusing type" irradiation port for "Proof-of-Principle" . This sub-mm port produces 1mm(1σ) beam. we will explain this irradion port at the conference. |
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THPS075 | Recent Progress of New Cancer Therapy Facility at HIMAC | 3604 |
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Since 1994, the carbon beam treatment has been continued at Heavy Ion Medical Accelerator in Chiba (HIMAC). The total number of patients treated is more than 5,000 in 2010. Based on more than ten years of experience with HIMAC, we have developed new treatment equipments toward adaptive cancer therapy with heavy ion at New Particle Therapy Research Facility in NIRS. | ||