| Paper | Title | Page |
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| WEPB01 | Status Report on the Operation of the RIBF Ring Cyclotrons | 191 |
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| Operational status of four ring cyclotrons (RRC, fRC, IRC, SRC) from August 2014 to July 2015 is reported. We are engaging in the improvements and adjustments for increasing beam intensities year after year, and maintenances for the stabilization of beam supply. In these contributions, we will report the past performances of accelerated beams, statistics of operational and tuning time on corresponding period, as well as failures and copings with them. | ||
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| WEPB14 | Heavy-Ion Beam Acceleration at RIKEN for the Super-Heavy Element Search | 222 |
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| The RIKEN heavy ion linac (RILAC) is composed of a variable-frequency Wideröe linac, an 18 GHz ECR ion source, a variable-frequency folded-coaxial radio frequency quadrupole linac (FC-RFQ) as a pre-injector, and a Charge-State Multiplier system (CSM) as a booster. The operation of RILAC was started to supply heavy ion beams for experiments in 1981. The 18 GHz ECR ion source and the FC-RFQ were installed in 1996. The CSM was installed in 2000. The maximum beam energy, boosted by the CSM, is 6.0 MeV/nucleon. A GAs-filled Recoil Isotope Separator (GARIS) was moved from the E1 experiment room of the RRC to the No. 1 target room of the RILAC in 2000. In RIKEN Nishina center, the experiment on the super-heavy element (Z=113) search was carried out at RILAC from September 2003 to October 2012. As a result, three events for Z=113 have been successfully observed. The heavy-ion beam acceleration at RIKEN for the super-heavy element search will be reported. | ||
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| WEPB22 | Supply of Metallic Beams from RIKEN 18-GHz ECRIS Using Low-Temperature Oven | 244 |
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| In the RIKEN 18-GHz electron cyclotron resonance ion source, the practical use of low-temperature oven was achieved for the supply of metallic beams. At the RIKEN Radioisotope Beam Factory, Ca-48 beam is one of the important beams, as a primary beam to produce the secondary beam of neutron-rich medium-heavy nuclei. In order to enhance the intensity and stability of Ca-48 beam, we newly introduced a low-temperature oven and so-called "hot liner." A mixture of CaO and Al powders was placed into the crucible of the oven and heated to produce metallic calcium by a reductive reaction. We succeeded in high-intensity and stable supply of Ca-48 beam, as well as the reduction of material consumption rate. In addition, we succeeded in the supply of Zn-70 beam using the low-temperature oven. In supplying Zn-70 beam, only the ZnO powder was placed into the crucible, and the hot liner was not used. In this contribution, the configuration of low-temperature oven, the effect of the hot liner, the supply situations of Ca-48 and Zn-70 beams for a long-term experiment, and the attempts to supply other metallic beams using the low-temperature oven will be reported. | ||
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THM1C01 |
Further Improvement of Performance of RIKEN 28GHz SC-ECRIS and Search for the Optimum Structure of ECR Ion Sources | |
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| To search for the optimum structure of the ECR ion source, we studied the effect of the main parameters (magnetic field, etc) of RIKEN SC-ECRIS on the beam intensity for various heavy ions (Ar~U) with 18 and 28GHz. In the systematic studies, we observed that the beam intensity is strongly dependent on these parameters. For examples, optimum value of Bmin for maximizing the beam intensity was dependent on the microwave frequency (~0.8Becr (18GHz), 0.6~0.65Becr (28GHz)) and gas pressure. We found that the optimum value of Br to maximize then beam intensity is strongly dependent on Bmin in a certain condition. Based on these studies, even though we used the magnetic field lower than the ordinary "High-B mode", we obtained more than 200euA of U35+ at lower RF power. We could dramatically reduce the consumption rate of metal U form ~8.6 to ~2.8mg/h to produce 150euA of U35+. In this contribution, we present the effect of main parameters on the beam intensities for various heavy ions and mechanisms in detail. We show how to optimize the performance to obtain the intense U beam. Based on these studies, we also describe the optimum structure for higher microwave frequency. | ||
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Slides THM1C01 [2.407 MB] | |
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