Superconducting magnet system for a 28GHz ECR ion source has been designed.The maximum axial magnetic fields are 4T at the rf injection side and 2T at the beam extraction side,respectively.The hexapole magnetic field ...Superconducting magnet system for a 28GHz ECR ion source has been designed.The maximum axial magnetic fields are 4T at the rf injection side and 2T at the beam extraction side,respectively.The hexapole magnetic field is about 2T on the inner surface of the plasma chamber.The superconducting coils consist of six solenoids and six racetrack windings for a hexapole field.Two kinds of coil arrangements were investigated:one is an arrangement in which the hexpole coil is located in the bore of the solenoids,and another is the reverse of it.The coils use NbTi-Copper conductor and are bath-cooled in liquid helium.The six solenoids are excited with individual power supplies to search for the optimal axial field distribution.The current leads use high Tc material and the cryogenic system is operated in LHe re-condensation mode using small refrigerators.The thermal insulated supports of the cold mass have also been designed based on the calculated results of the magnetic force.The heat loads to 70K and LHe stages were estimated from the design of the supports,the current leads and so on.展开更多
We measured the main plasma parameters（density of electron,temperature of electron and ion confinement time）and beam intensity of various heavy ions as a function of B<sub>min</sub>.The B<sub>min&l...We measured the main plasma parameters（density of electron,temperature of electron and ion confinement time）and beam intensity of various heavy ions as a function of B<sub>min</sub>.The B<sub>min</sub> strongly affects the field gradient at the resonance zone,consequently the plasma parameters and beam intensity are changed. Based on these experimental results,we started to construct new 18GHz ECRIS and make a detailed design of the 28GHz SC-ECRIS for RIKEN RI beam factory project.展开更多
At RIKEN,three ECR ion sources（10GHz ECRIS,18GHz ECRIS and liquid He-free SC-ECRIS） are operated as external ion sources of heavy ion accelerators.In the last year,multi-charged uranium ion beam was produced from 18...At RIKEN,three ECR ion sources（10GHz ECRIS,18GHz ECRIS and liquid He-free SC-ECRIS） are operated as external ion sources of heavy ion accelerators.In the last year,multi-charged uranium ion beam was produced from 18GHz ECRIS by using UF<sub>6</sub> and the <sup>238</sup>U ion was successfully accelerated by the accelerator complex which consists of the RFQ linear accelerator,RIKEN heavy ion linear accelerator（RILAC）and RIKEN ring cyclotron accelerator（RRC）.The typical beam intensity of<sup>238</sup>U<sup>14+</sup> was about 2pμA on faraday cup after analysing magnet.<sup>70</sup>Zn beam was still supplied for the new super-heavy element search experiment with insertion method.Intense beam of<sup>70</sup>Zn<sup>16+</sup> was produced for long term（～43 days）without vacuum break and remarkably low material consumption rate（～100μgr/h）.We already supplied Zn beam longer than 200 days for this experiment.<sup>48</sup>Ca ion was also produced by insertion method using<sup>48</sup>CaO rod for the nuclear physics experiment.In this contribution,we will present ion source parameter and techniques for production of each of the metal ions.展开更多
文摘Superconducting magnet system for a 28GHz ECR ion source has been designed.The maximum axial magnetic fields are 4T at the rf injection side and 2T at the beam extraction side,respectively.The hexapole magnetic field is about 2T on the inner surface of the plasma chamber.The superconducting coils consist of six solenoids and six racetrack windings for a hexapole field.Two kinds of coil arrangements were investigated:one is an arrangement in which the hexpole coil is located in the bore of the solenoids,and another is the reverse of it.The coils use NbTi-Copper conductor and are bath-cooled in liquid helium.The six solenoids are excited with individual power supplies to search for the optimal axial field distribution.The current leads use high Tc material and the cryogenic system is operated in LHe re-condensation mode using small refrigerators.The thermal insulated supports of the cold mass have also been designed based on the calculated results of the magnetic force.The heat loads to 70K and LHe stages were estimated from the design of the supports,the current leads and so on.
文摘We measured the main plasma parameters（density of electron,temperature of electron and ion confinement time）and beam intensity of various heavy ions as a function of B<sub>min</sub>.The B<sub>min</sub> strongly affects the field gradient at the resonance zone,consequently the plasma parameters and beam intensity are changed. Based on these experimental results,we started to construct new 18GHz ECRIS and make a detailed design of the 28GHz SC-ECRIS for RIKEN RI beam factory project.
文摘At RIKEN,three ECR ion sources（10GHz ECRIS,18GHz ECRIS and liquid He-free SC-ECRIS） are operated as external ion sources of heavy ion accelerators.In the last year,multi-charged uranium ion beam was produced from 18GHz ECRIS by using UF<sub>6</sub> and the <sup>238</sup>U ion was successfully accelerated by the accelerator complex which consists of the RFQ linear accelerator,RIKEN heavy ion linear accelerator（RILAC）and RIKEN ring cyclotron accelerator（RRC）.The typical beam intensity of<sup>238</sup>U<sup>14+</sup> was about 2pμA on faraday cup after analysing magnet.<sup>70</sup>Zn beam was still supplied for the new super-heavy element search experiment with insertion method.Intense beam of<sup>70</sup>Zn<sup>16+</sup> was produced for long term（～43 days）without vacuum break and remarkably low material consumption rate（～100μgr/h）.We already supplied Zn beam longer than 200 days for this experiment.<sup>48</sup>Ca ion was also produced by insertion method using<sup>48</sup>CaO rod for the nuclear physics experiment.In this contribution,we will present ion source parameter and techniques for production of each of the metal ions.
