Paper | Title | Page |
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MOP057 | Linac Front-End Upgrade at the Cancer Therapy Facility HIT | 208 |
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A clinical facility for cancer therapy using energetic proton and ion beams (C, He and O) has been installed at the Radiologische Universitätsklinik in Heidelberg, Germany. It consists of two ECR ion sources, a 7 MeV/u linac injector, and a 6.5 Tm synchrotron to accelerate the ions to energies of 430 MeV/u. The linac comprises a 400 keV/u RFQ and a 7 MeV/u IH-DTL operating at 216.8 MHz and has been commissioned successfully in 2006. Yet the overall achieved transmission through the injector linac did not exceed 30% due to a mismatch of the beam at the RFQ entrance. Thus a detailed upgrade programme has been started to exchange the RFQ with a new radial matcher design, to correct the alignment and to optimize beam transport to the IH-DTL. The aim is to achieve a sufficient linac transmission above 60%. The new design of the RFQ has been finished in 2007 and the RFQ is currently in production. A test bench comprising a full ion source and LEBT setup to commission the RFQ in 2008 is under construction at Danfysik in Danemark. The current status of this upgrade programme will be reported in this contribution. |
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MOP059 | C6+ Ion Hybrid Single Cavity Linac with Direct Plasma Injection Scheme for Cancer Therapy | 211 |
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We succeeded to accelerate very intense carbon ions with the Direct Plasma Injection Scheme (DPIS) using Laser ion source in 2001 and 2004. The peak current reached more than 60 mA of C4+ and 18 mA of C6+ with pulse width of 2-3 x 10-6 sec. We believe that these techniques are quite effective for pulse accelerator complexes such as linear accelerator and synchrotron (heavy-ion cancer therapy). In heavy cancer therapy, carbon stripper section is rejected by accelerated C6+. One turn injection of high intensity (6 mA) C6+ ion is possible to enough in synchrotron. We study a new hybrid single cavity linac combined with radio frequency quadrupole (RFQ) electrodes and drift tube(DT) electrodes into a single cavity. The hybrid linac is able to downsize the linac system and reduce the peripheral device. Using DPIS with Laser ion source, we study POP hybrid single-cavity accelerator of C6+ for injector linac of C cancer therapy. The linac is designed to accelerate 6 mA C6+ ion from 40 keV/u to 2 MeV/u with YAG Laser ion source. We will present the design procedures of this hybrid linac, which is based on a three-dimensional electromagnetic field and particle orbit calculation. |
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MOP060 | Quality Improvement of Laser-produced Protons by Phase Rotation and its Possible Extension to High Energies | 214 |
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Funding: This work is supported by Advanced Compact Accelerator project by MEXT of Japanese Government and 21COE of Kyoto University, Center for Diversity and Universality in Physics. * Japanese Journal of Applied Physics (Express Letter), 46 (2007) L717-L720 |
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MOP061 | The Feasibility of Low-Energy Electronuclear Power Plant | 217 |
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Funding: Rosatom corp. |
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MOP062 | CW Proton Linac for the BNCT Application | 220 |
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A 2.5 MeV, 20 mA, cw, proton linac for the Boron Neutron Capture Therapy medical application is under construction at Linac Systems. The system consists of a 25 keV microwave ion source, a solenoid lens based low energy beam transport system, a 0.75 MeV RFQ linac, a 2.5 MeV RFI linac, and the necessary service systems. Because of the superb low energy capabilities of the RFI structure, the RFQ linac need only go to 0.75 MeV, resulting in a cavity dissipation of 74 kW for the RFQ section. Because of the high rf efficiency of the RFI structure, the cavity dissipation is only 35 kW for the RFI section. Extensive thermal studies have been made to accommodate these cw heat load. The beam power is 50 kW. The rf power system is designed for an average power output of 200 kW. The RFQ and RFI sections are coupled into a single resonant unit by a quarter-wave-stub resonant coupler. The combination is driven at a single point in the RFQ structure. The total length of the linac is 2.6 meters. The system is scheduled for completion by early fall (2008). |
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MOP063 | High-Power Lithium Target for Accelerator-Based BNCT | 223 |
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A 50 kW, water-cooled conical target for producing neutrons via the Li-7(p,n)Be-7 reaction at 2.5 MeV proton energy is under development at Linac Systems. This target is intended to accept a stationary, expanded CW beam with a diameter of 8 cm directly from an rf linac, resulting in peak surface heat flux of 7.5 MW m-2 (a 'waterbag' beam power distribution is assumed). The target is predicted to meet the intensity requirements for practical accelerator-based boron neutron capture therapy (BNCT), in concert with Linac Systems' CW RFI linac. Lithium metal targets present well-known physical and mechanical challenges at high beam power density that are addressed in our design. For instance, lithium melts at 180 C, necessitating efficient removal of heat at a low ΔT relative to ambient temperature. CFD modeling indicates that with 50 kW incident beam power, the peak lithium temperature can be held below 150 C with a water flow rate near 80 l min-1 and corresponding pressure drop of 170 kPa. The target prototype has been fabricated and is undergoing experimental thermal-hydraulic testing using an electron beam at the Plasma Materials Test Facility, Sandia National Laboratory. |
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WE204 | IH-DTL as a Compact Injector for a Heavy-Ion Medical Synchrotron | 715 |
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An interdigital H-mode structure drift tube linac (IH-DTL) with alternating phase focusing (APF) has been developed downstream of a 4-vane type RFQ linac at the National Institute of Radiological Sciences as a compact injector for a heavy-ion medical synchrotron. The rf frequency of both linacs is 200 MHz, and the total length of the two linacs is less than 6 m. They can accelerate heavy ions having a charge to mass ratio of 1/3 up to 4 MeV/u. The accelerated current of 12C4+ is as high as 380 electric μA, and beam transmission through the APF IH-DTL is better than 96%. This compact injector-linac scheme might give a possible solution for a compact cancer therapy facility with heavy-ion beams. |
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WE205 | Commissioning and Operation of the Injector Linacs for HIT and CNAO | 720 |
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The Heidelberg Ion-Beam Therapy Centre (HIT) is the first dedicated clinical synchrotron facility for cancer therapy using energetic proton and ion beams (C, He and O) in Europe. The accelerator consists of a 7 MeV/u, 217 MHz injector linac and of a 430 MeV/u synchrotron. The installation and commissioning of the linac has been performed gradually in three steps for the ion sources and the LEBT, for the 400 keV/u RFQ, and for the 20 MV IH-type drift tube linac. The initial commissioning of the linac was finished successfully in December 2006, the commissioning of the synchrotron and of the high-energy beam lines with beam was finished for two fixed-beam treatment places in December 2007. Commissioning of the heavy-ion gantry is still going on. The results of the linac commissioning will be reported as well as the experience of more than one year of linac operation. To provide optimum conditions for patient treatment, an intensity upgrade programme has been initiated for the linac. A copy of the HIT linac is presently installed at the Centro Nazionale di Adroterapia Oncologica (CNAO) in Pavia, Italy. The status of the CNAO linac will be also reported. |
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