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Abstract: New measurements of the total and partial fragmentation cross-sections in the energy range 0.3÷10AGeV of Fe26+, Si14+ and C6+ beams on polyethylene, CR-39 and aluminum targets are presented. The exposures were made at Brookhaven National Laboratory (BNL), USA, and Heavy Ion Medical Accelerator in Chiba (HIMAC), Japan. The CR-39 nuclear track detectors were used to identify the incident and survived beam ions and their fragments. The total fragmentation cross-sections for all targets are almost energy independent while they depend on the target mass. The measured partial fragmentation cross-sections are also discussed. [Copyright &y& Elsevier]

Abstract: A 3D-scanning irradiation method gated with the patient''s respiration has been developed for the new Heavy Ion Medical Accelerator treatment facility in Chiba. The RF-knockout slow-extraction method has been used for fast on/off switching of the beam from the synchrotron during scanning irradiation. However, a small amount of beam that remained just inside the separatrix spilled out even without the transverse RF field, and limits the controllable low beam rate. We proposed to apply another transverse RF field with a frequency component matched with the betatron frequency of particles near the stopband in addition to the original transverse RF field. The particles just inside the separatrix can be selectively extracted during the irradiation, and the uncontrollable spilled beam can be suppressed. The spilled beam was measured with the ion chamber, and was reduced to 0.4% compared to the original method. [Copyright &y& Elsevier]

Abstract: Measurements of primary g-values (at ∼10−7 s after the initial ionizing event) of , OH and H2O2 were extended to the very high linear energy transfer (LET) region (∼700eV/nm) near the Bragg peak. Heavy ions (4He2+, 12C6+, 20Ne10+, 28Si14+, 40Ar18+ and 56Fe26+) of energies up to 28GeV were provided by the Heavy Ion Medical Accelerator in Chiba (HIMAC) of the National Institute of Radiological Sciences (NIRS) in Chiba, Japan. Energies of the ions were decreased down to about 10MeV/u for 4He2+ using an energy absorber made of polymethylmethacrylate (PMMA) plates in order to vary the LET values. Beam was visualized after passing through the energy absorber using agarose gel of aqueous solution containing methyl viologen and sodium formate in order to determine how long ions can penetrate into water. Based on the information of the penetration depth of ions in samples, much attention was paid to dose correction and LET evaluation. The obtained data were plotted as a function of (Z eff/β)2 also instead of LET in order to discuss effects of physical track structures on product yields, resulted in better universality. [Copyright &y& Elsevier]

Abstract: Heavy-ion therapy is one of the important methods for the cancer treatment. More than 3400 patients were treated between 1994 and 2007 at Heavy Ion Medical Accelerator in Chiba (HIMAC). For the promotion of carbon-ion therapy, a compact carbon-therapy facility was developed. The size of the new facility is three times smaller, while the accelerator can supply the beams similar to those used at HIMAC. The new irradiation system was developed in order to obtain a precise dose distribution for moving and/or deforming organs. [Copyright &y& Elsevier]

The effective doses and attenuation lengths for concrete and iron were measured for the design of heavy ion facilities. Neutrons were produced through the reaction of copper, carbon, and lead bombarded by carbon ions at 230 and 400 MeV·A, neon ions at 400 and 600 MeV·A, and silicon ions at 600 and 800 MeV·A. The detectors used were a Linus and a Andersson­Braun-type rem counter and a detector based on the activation of a plastic scintillator. Representative effective dose rates (in units of 10-8 μSv h-1 pps-1 at 1 m from the incident target surface, where pps means particles per second) and the attenuation lengths (in units of m) were 9.4 × 104, 0.46 for carbon ions at 230 MeV·A; 8.9 × 105, 0.48 for carbon ions at 400 MeV·A; 9.3 × 105, 0.48 for neon ions at 400 MeV·A; 3.8 × 106, 0.50 for neon ions at 600 MeV·A; 3.9 × 106, 0.50 for silicon ions at 600 MeV·A; and 1.1 × 107, 0.51 for silicon ions at 800 MeV·A. The attenuation provided by an iron plate approximately 20 cm thick (nearly equal to the attenuation length) corresponded to that of a 50-cm block of concrete in the present energy range. Miscellaneous results, such as the angular distributions of the neutron effective dose, narrow beam attenuation experiments, decay of gamma-ray doses after the bombardment of targets, doses around an irradiation room, order effects in the multi-layer (concrete and iron) shielding, the doses from different targets, the doses measured with a scintillator activation detector, the gamma-ray doses out of walls and the ratio of the response between the Andersson­ Braun-type and the Linus rent counters are also reported. [ABSTRACT FROM AUTHOR]