75 MeV/u oxygen ion (^16O+8) beams supplied by HIRFL were used to irradiate 14615 of spring wheat dry seeds of stable multi-generation. Range of the ions in the seeds is about 11 mm. They can enter the seed from its e...75 MeV/u oxygen ion (^16O+8) beams supplied by HIRFL were used to irradiate 14615 of spring wheat dry seeds of stable multi-generation. Range of the ions in the seeds is about 11 mm. They can enter the seed from its embryo, come out from its top, and penetrate through an entire grain of wheat, length of which is about 6～7 mm. The seeds were vertically inserted in a sample plate of 4 cm in diameter, which can contain about 100 grain of the seeds. During irradiation, the embryo of the seeds faced to ion beams and was irradiated at normal temperature and atmosphere. Irradiation dose was arranged in 1×10^7, 5×10^7, 1×10^8, 2×10^8 and 5×10^8 ions/cm^2 with dose rate of about 3 Gy/min. A part of the irradiated seeds was employed for cytology examination in laboratory, the others were used for breeding in the fields.展开更多
The distinguishing feature and current technique progress of tumor treatment with heavy-ion beams is introduced in the paper. Additional superiority to tumor treatment from a radioactive ion beam (RIB) is emphatically...The distinguishing feature and current technique progress of tumor treatment with heavy-ion beams is introduced in the paper. Additional superiority to tumor treatment from a radioactive ion beam (RIB) is emphatically discussed. The experimental research of the radioactive 9C-ion beams aimed at tumor treatment at Heavy Ion Medical Accelerator in Chiba (HIMAC), National Institute of Radiological Sciences (NIRS), Japan is described in detail, La-eluding production of the beams, optimization of parameters, distribution of depth dose, survival effect of cell and comparison of RBE between 9C- and 12C-beams. Results show that under 40 mm thick Beryllium target and 10 mm thick aluminum degrader at full (5%) momentum acceptance, the production rate and purity of the produced 9C-beams are 9.07×10-6 and 82.88% respectively with the primary 12C-beams of 430 MeV/u and 1.8×109 pps. A uniform irradiation field with homogeneity up to 89.6% inside central area 10 mm in diameter is obtained by using spot scanning. In this case, the dose rate at the entrance is 0.5 Gy/h. In survival experiment of cells, the average relative biological effectiveness (RBE) of 9C-beams is 5.28 and 2.93 for 12C-beams in the region around Bragg peak. The RBE of 9C-beams is 1.8 times higher than that of 12C-beams. It indicates that cell-killing efficiency of 9C-beams is stronger than that of 12C-beams. 9C-beams are more efficacious for tumor treatment than 12C-beams.展开更多
文摘75 MeV/u oxygen ion (^16O+8) beams supplied by HIRFL were used to irradiate 14615 of spring wheat dry seeds of stable multi-generation. Range of the ions in the seeds is about 11 mm. They can enter the seed from its embryo, come out from its top, and penetrate through an entire grain of wheat, length of which is about 6～7 mm. The seeds were vertically inserted in a sample plate of 4 cm in diameter, which can contain about 100 grain of the seeds. During irradiation, the embryo of the seeds faced to ion beams and was irradiated at normal temperature and atmosphere. Irradiation dose was arranged in 1×10^7, 5×10^7, 1×10^8, 2×10^8 and 5×10^8 ions/cm^2 with dose rate of about 3 Gy/min. A part of the irradiated seeds was employed for cytology examination in laboratory, the others were used for breeding in the fields.
文摘The distinguishing feature and current technique progress of tumor treatment with heavy-ion beams is introduced in the paper. Additional superiority to tumor treatment from a radioactive ion beam (RIB) is emphatically discussed. The experimental research of the radioactive 9C-ion beams aimed at tumor treatment at Heavy Ion Medical Accelerator in Chiba (HIMAC), National Institute of Radiological Sciences (NIRS), Japan is described in detail, La-eluding production of the beams, optimization of parameters, distribution of depth dose, survival effect of cell and comparison of RBE between 9C- and 12C-beams. Results show that under 40 mm thick Beryllium target and 10 mm thick aluminum degrader at full (5%) momentum acceptance, the production rate and purity of the produced 9C-beams are 9.07×10-6 and 82.88% respectively with the primary 12C-beams of 430 MeV/u and 1.8×109 pps. A uniform irradiation field with homogeneity up to 89.6% inside central area 10 mm in diameter is obtained by using spot scanning. In this case, the dose rate at the entrance is 0.5 Gy/h. In survival experiment of cells, the average relative biological effectiveness (RBE) of 9C-beams is 5.28 and 2.93 for 12C-beams in the region around Bragg peak. The RBE of 9C-beams is 1.8 times higher than that of 12C-beams. It indicates that cell-killing efficiency of 9C-beams is stronger than that of 12C-beams. 9C-beams are more efficacious for tumor treatment than 12C-beams.
