Korea Atomic Energy Research Institute Byung-Hoon Oh, Sang-Ryul In, Kwang-Won Lee, Chang Seog Seo*, Jung-Tae Jin, Dae-Sik Chang, Seong Ho Jeong, Chul-Kew Hwang, Tae-Sung Kim, Cheol Ho Lee * Institute of Basic Science Conceptual Design of a Superconducting Magnet ECR Ion Source for the Korea Rare Isotope Accelerator

NUCLEAR for CLEAN KOREA CONTENTS  Introduction  Summary of Characteristics of SC ECRIS Model  Double solenoid lens system  Magnetic field structure  Key parameters  Overall structure  Needed prototype fabrication  Summary

NUCLEAR for CLEAN KOREA Worldwide status on SM ECRIS development  All of the big facilities for heavy ion beam have their own SM ECRIS model;  Main reasons of this are; - ion source performance is closely related with accelerator performance, - ECRIS development and upgrade is still on-going for; highly charged beam high current small emittance beam for LEBT/ RFQ acceptance oven life and so on. acceleratorSM ECRIScountry 88 inch cyclotronVENUSUSA RIBFRIKEN ECRISJapan K-800 SM cyclotronMS-ECRISItalia HIRFLSECRALChina FAIRSuSIUSA

NUCLEAR for CLEAN KOREA  Based on the proven technology,  conceptual design of an 28 GHz superconducting ECR ion source is in progress  to produce wide range of different ion beams from proton to uranium  in high quality and high current beam. Main target of the SM ECRIS  Main parameters - beam current U U U 35+ > 500 μA (conservative) proton equivalent 30 mA - B z,entrance / B r / B z,exit > 4.0T/ 2.2T/ 3.0T (VENUS 4.0T/2.0T/3.0T) (RIKEN 3.8T/2.1T/2.4T) - beam extraction voltage 30 keV - characteristics high intensity low envelope

NUCLEAR for CLEAN KOREA The designed ECRIS has the following characteristics: (1)Minimum B z layer can be controlled with five superconducting solenoid coils. (2)B z field higher than 4 T at the entrance and higher than 3 T at the exit could be achieved with the 5 solenoid coils. (3)B r field higher than 2.2 T will be realized with saddle winding and thicker conductor for the sextupole magnet. (4)Double solenoid lenses, the first one in a cryo tank and the second one at the outside of it, are used to improve the beam transport efficiency. (5)Shielding for the hard X-ray is reinforced. With these characteristics the ECRIS could produce higher intensity beams with smaller beam envelopes compared with those of other present ion sources. Characteristics of the suggested SC ECRIS

NUCLEAR for CLEAN KOREA CONTENTS  Introduction  Characteristics of SC ECRIS Model  Double solenoid lens system  Magnetic field structure  Key parameters  Overall structure  Needed prototype fabrication  Summary

NUCLEAR for CLEAN KOREA  To get small envelope beam after a bending magnet ` -Smaller beam at the entrance of a bending magnet makes smaller size and smaller divergence beam after the bending magnet. -To make small envelope beam after the bending magnet, it is recommended to make parallel and small size beam at the entrance of the magnet. - small envelope beam in red - large envelope beam in green - all beams are focused at the same point

NUCLEAR for CLEAN KOREA - Single & double solenoid lens system before a bending magnet With single solenoid -Usually for the SM ECRIS -the solenoid position is determined -by the cryo tank structure. -Because of it, for a high current beam, -large beam by space charge expansion -is inevitable. Solenoid 1 Solenoid 2 With double solenoids -If the first solenoid lens is installed in a cryo tank -to shortening the length of the drift space, -and the second one at the outside of the cryo, -we could get

NUCLEAR for CLEAN KOREA The Effects with two-solenoid-lens system -The system can actively control the angle and beam size at the entrance of BM depending on beam current and beam species. -The first lens near the beam extraction grid minimizes the envelope glowing caused by the space charge and others. -The second lens near the BM controls the beam size and angle at the entrance of BM. -These can make high current and small envelope image at the entrance of BM. -Finally we can get needed species at the exit of BM with small envelope in a large beam current.

 U - high current extraction (30 mA equivalent) without sol. lens sol lens cryo-IN Single sol. lens VENUS position double sol. lens

 proton (10 mA) extraction Space charge effect dominant without sol. lens sol lens cryo-IN double sol. lens Single sol. lens VENUS position

NUCLEAR for CLEAN KOREA CONTENTS  Introduction  Characteristics of SC ECRIS Model  Double solenoid lens system  Magnetic field structure  Key parameters  Overall structure  Needed prototype fabrication  Summary

NUCLEAR for CLEAN KOREA Designed ECRIS magnets and field structure - Five solenoids for B min control - Saddle type winding - Yoke length 340 mm 4.1 T 2.6 T 2.2 T St0 St1 St2 SL1 SL2 B min layer control BrBr BzBz

NUCLEAR for CLEAN KOREA Axial Magnet layout of the designed ECRIS

NUCLEAR for CLEAN KOREA Axial field along the beam axis on the YOKE existence Solenoid field pattern in case of the Flat B min w/ YOKE classicalflat B min B z,in > 4.2 T> 4.0 T B z,out > 3.2 T3.0 T

NUCLEAR for CLEAN KOREA Parameter of the superconducting coils SC Coils

NUCLEAR for CLEAN KOREA CONTENTS  Introduction  Characteristics of SC ECRIS Model  Double solenoid lens system  Magnetic field structure  Key parameters  Overall structure  Needed prototype fabrication  Summary

NUCLEAR for CLEAN KOREA VENUSRIKENKAERI Chamber ID (OD) thickness 140 (160) mm 10 mm 150 (164) mm 7 mm 144 (158) mm 7 mm Sextupole ID (OD)200 (272) mm204 (284) mm200 (284) gap btwn chamber & sextupole 20 mm 21mm Chamber 길이 510 mm525 mm530 mm Chamber volume7.8 litter9.2 litter8.6 liter  Chamber parameters are critical to make strong magnet & high density plasma  Chamber HV insulation at 4 positions - 2 mm PEEK for magnet - brazed ceramic for beam extraction electrode - teflon (PEEK) tube between input box and magnet - RF DC break for RF system  X-ray shielding - with 3 mm Ta - increase the cryo cooling capacity Critical parameters of three SM-ECRIS

NUCLEAR for CLEAN KOREA Radial Buildup of multiple layers  The multilayer structure, especially the inner side, is very compact and need more considerations including the EM force.

NUCLEAR for CLEAN KOREA Cryogenic Power Balance

NUCLEAR for CLEAN KOREA CONTENTS  Introduction  Characteristics of SC ECRIS Model  Double solenoid lens system  Magnetic field structure  Key parameters  Overall structure  Needed prototype fabrication  Summary

NUCLEAR for CLEAN KOREA ECRIS 6-body structure 1.Superconducting magnet structure 2.Plasma chamber 3.Input chamber 4.Beam extraction chamber 5.Bending magnet 6.RF system  Each structure could be separated independently, and maintenance plans will be prepared based on this 6-body structure.

NUCLEAR for CLEAN KOREA Layout Sketch of the designed ECRIS  Minimize the distance between beam extraction hole and BM.  Extraction gap could be controlled by spacer ring thickness.  Input port & output port could be removed with small effort for maintenance.

NUCLEAR for CLEAN KOREA CONTENTS  Introduction  Characteristics of SC ECRIS Model  Double solenoid lens system  Magnetic field structure  Key parameters  Overall structure  Needed prototype fabrication  Summary

NUCLEAR for CLEAN KOREA Prototype module for Sextupole windings  Saddle type winding in a long thick layer needs a specific winding zig.  The effectiveness of the zig for saddle winding should be confirmed. RIKEN type VENUS type KBSI type

NUCLEAR for CLEAN KOREA A prototype for Helium re-condensation test 4K Cooler GHe LHe Main purpose of the prototype is to condenser design and - to estimate the LiHe volume to be recovered with a 1.5 W electric cooler.

NUCLEAR for CLEAN KOREA CONTENTS  Introduction  Characteristics of SC ECRIS Model  Double solenoid lens system  Magnetic field structure  Key parameters  Overall structure  Needed prototype fabrication  Summary

NUCLEAR for CLEAN KOREA Summary and Comments  We are suggesting an upgrade model based on the proven technology for the SM ECRIS during CDR work.  The worldwide mood for the collaboration related with ECRIS is very warm, and therefore with close relationships with other teams we hope to succeed the development successfully despite of our short experience.  The SM ECRIS could contribute to differentiate Korea heavy ion accelerator from other recent RIA machines.  And also could contribute something to the global ECR society.

NUCLEAR for CLEAN KOREA Thank you very much for your attention.

NUCLEAR for CLEAN KOREA Multi-charged Ion Beam Extraction & Separation Result _Argon(A=18)

NUCLEAR for CLEAN KOREA Gas pressure 3.5x mbar RF power: 600 W Carbon beam separation result with CO 2 gas 15 μA

NUCLEAR for CLEAN KOREA - Beam Emittance Measurement * 130 π mm mrad

NUCLEAR for CLEAN KOREA Cost Estimation 1.SM ECRIS fabrication (5-year work) (1)Hardware total 4.5 M$ RF system 0.5 M$ SM Magnet/ Cryo/ plasma chamber1.5 M$ Beam extraction and transport 0.2 M$ Bending magnet 0.3 M$ Beam diagnostics0.2 M$ Power Supplies1.0 M$ Control system 0.3 M$ Contingency 0.5 M$ (2) Manpower cost total3.0 M$ 0.6 M$/year x 5 year3.0 M$

NUCLEAR for CLEAN KOREA Developments Plan – finalize CDR and start fabrication design finalize fabrication design and start to fabricate fabrication of SM magnet system and test – fabrication of beam extraction and transport system beam extraction and diagnostics beam injection to the RIA

NUCLEAR for CLEAN KOREA H3010 Xe (131)O Xe Xe Xe Xe Xe Xe total U (238)O U U U U U U Total IGUN Input current (mA) H equivalent Current (mA) IGUN Input current (mA) H equivalent Current (mA) IGUN input current estimation

IGUN beam extraction simulation with double solenoid - 30 mA proton equivalent beam - main consideration beam U U U μA Xe Xe Xe mA H + 10 mA - Beam extraction voltage30 kV -Exit solenoid B z (3T) included -Solenoid lens -Bending magnet entrance is at 120 cm (BM focal length 110 cm) Sextupole 3cm gap for setupole structure/ cryo tank case VENUS solenoid position Sol. Lens cryo In Sol. Lens cryo Out Exit Sol.