2007/2/111 A Report to the Advisory Committee of CNS The Accelerator Group Outline Progress in April – December 2006 Schedule in Jan – March 2008 Upgrade of AVF Cyclotron Shigeru Kubono, Yukimitsu Ohshiro, Shin-ichi Watanabe. Syoichi Yamaka(CNS) Sergey B. Vorozhtsov, Alexey S. Vorozhtsov, Evegeny E. Perepelkin (JINR) Akira Goto, Masayuki Kase (RIKEN) Toshinori Mitsumoto (SHI), Mitsuhiro Fukuda (RCNP)

2007/2/112 １０ GH ｚ ECR Layout of AVF Cyclotron HyperECR AVF Cyclotron Room E7 R ext =0.714m B max =1. 7 T Vrf = 50 kV h =2 F 0 =12~24MHz FC-I36 FC-C01a FC-I10 Cycro center FC-F0 CRIB

2007/2/113 K-value70 MeV M/Q 2 Acc.Beam 14 N MeV/u Average Max.field17 kG Extraction radius714 mm Dee angle83°x2 Dees Voltage peak 50 kV RF frequency12-24 MHz RF power2 x 50 kW Main coil power180 kW (1100 A) Circular coil8 pairs Harmonic coil4 pairs Vacuum pump1500 l/s TMP x l/s CRYO x l/s CRYO x1 Manufactured1989 Specifications of RIKEN AVF

2007/2/114 １９９ ７ １９ ９８ １９９ ９ ２００ ０ ２００ １ ２００ ２ ２００ ３ ２００ ４ ２００ ５ ２００ ６ ２０ ０７ HyperECR Improve SF ECR BT Charge breeder AVF Flat top High power RF Main & Trim coil Center region Improvements Beam line E7(CRIB) SF clean up PA Monitor DCCT Cluster Rf buncher VIS JSPS foundation Atomic Physics 10 years over view Cold modelhot modelTuningBeam testOperation K=80 InstallationMove to RIKEN Operation Design Monitor R&D Modify Improvement Design H=2,3H=1 Deflector CRIB Sputtering Ion source Mesh Move to RIKEN HiECR Accel-decel Metal ions InsulatorCondenser F0 focus Contribution to AVF upgrade Metal IS Glaser lens Insulator VIS Sputtering IS Rf buncher SQUID monitor

2007/2/115 Directivity of upgrade of the RIKEN AVF cyclotron (K70) *The advancement which aimed at the beam performance needed for Nuclear Astrophysics research. ① High energy by K value reinforcement (acceleration h = 2) → Main coil & trim coil power supply reconstruction ② Extension of an acceleration energy domain (Acceleration harmonics h = 1, 3) → Center region reconstruction High Energy by K80, 15 N 5+ 9MeV/u, 10p  A Acceleration harmonics h = 1, 2, 3 Energy per Nucleon (MeV/u) 磁場 (T) 1560 ｈ＝１ center region 42 ② ｈ＝２ (K-value ） Now in used ① ② ｈ＝３ center region The main point of AVF Upgrade

2007/2/116 What is advanced in 2006? 1. Ion source HyperECR Ion source / Metal ions New ion source / Charge breeder ECR, Super ECR 2. Development of AVF Cyclotron Glaser lens New AVF control room / Shared RIBF space Dee RF / up to 52 kV 3.Upgrade of RIKEN/CNS AVF cyclotron Design study of B-field, E-field, Centering, Inflector, Dee chips, RF-shield, Injection, Extraction, Beam losses

2007/2/ Ion Source A. Hyper ECR The half of the machine schedule of RIKEN cyclotron uses the our HyperECR ion source. B. Metal Ion Source Si, Ca, P extracted from HyperECR C. Super ECR 5.5K is continued D. CBECR Under the setup and vacuum test Y. Ohshiro

2007/2/118 ★ Extracted beam from AVF cyclotron ○The typical beam intensity in this year (2006) is shown in the Table 1. ○Beam transmission efficiency of ECR- AVF cyclotron (C01/I36) 35% is realized. ○The half of the machine schedule of RIKEN cyclotron uses the our HyperECR ion.source. ★ Metal ion ○ Since the hot liner in the plasma chamber is attached, Li ion generation which used crucible can be stable and can take out the ions of large intensity. ○By having doubled the capacity of crucible, sample use time for one week or more was realized. A. Hyper ECR Ion Source Table 1 Y. Ohshiro

2007/2/119 Second stage ECR zone First stage ECR zone ⑦⑥ ④ ③ ② Center ① ⑤ ⑧ Fig. 2. The distance of the tips of the crucible and the rod placed in the plasma chamber. Table 2. Beam intensities of metallic ions obtained B. Development of Metal Ions ★ Sample insertion optimum position ○ When a crucible or a rod is placed near 1 st ECR zone with efficient consumption rate, the metal ions of large intensity is obtained. ○ The metal ions which can be used now is shown in Table 2.  ECR Bz (kG) This year Y. Ohshiro Fig. 1 Schematic drawing of Hyper ECR ion source together with mirror field distribution used for 40 Ca 11+ ions production. ① Plasma chamber, ② RF wall, ③ Solid material, ④ Movable rod, ⑤ Sextupole magnet, ⑥ MC1, ⑦ MC2, ⑧ Extractor

2007/2/1110 C. Development of SC-ECR Ion Source ★ Purpose. Extraction of multicharge ion beam reinforcement by AVF cyclotron. For example, since an Ar 11+ ion beam is 100e  A, compared with HyperECR, an about 3 times as many increase as this is expected. * Present condition. O It installed on the test bench of RIBF-B1. O Electric power and cooling water were fixed. O The freezer was overhauled. O The cooling test of a superconductivity wire was completed. O Cooling temperature is stable at 5.5 k. O A mirror coil power supply is under manufacture. Fig. 3. The superconductivity ECR ion source installed by the test bench at RIBF-B1 (SC-ECR) Y. Ohshiro, Tsukuba Univ.

2007/2/1111 * Purpose. 1) Inject Ar + to CBECR, and generates Ar 11+ of large intensity. 2) Inject the metal ion from the external metal ion source, and generate the metal ion (Li, etc) of large intensity. * The feature. 1) More than Ar + 10e  A incidence. 2)Large differential pumping system because of an improvement of the vacuum pressure. 3) Strengthening of slowdown efficiency. * Present status. 1) Under an setup end and a vacuum test. 2) Source test; end of the volume type ion source = 40 Ar e  A O sputtering type ion source; Test end. Al + =66 [enA], Li + =2 [enA].. Fig. 4. The charge breeder attached in the electromagnetic analyzer D. Development of CNS Charge Breeder Y. Ohshiro

2007/2/1112 ① ② ③ ④ ⑤ 14GHz RF ⑥ ⑦ ⑧ TMP1 TMP2 TMP cm E 2 E 3 E 4 Deceleration Acceleration Incident beam energy (10 keV +5 eV) ΔV 0 Voltage [kV] Fig. 5. A cross-sectional view of the CNS charges breeding system and potential map for injection of interest ions. ① Volume type ion source, ②④ Insulator (MC nylon), ③ Einzel lens (E 1-4 ), ⑤ Charge breeder ECR ion source (CBECR), ⑥ Plasma chamber, ⑦ Decelerator, ⑧ Conical wall. E1 Table 3. Specification of each device designed. Y. Ohshiro Charge Breeder (continued)

2007/2/ Development of AVF in 2006 Glaser Lens Old Glaser lens was damaged by coil trouble New Glaser lens 'GLI38' is installed. New Glaser lens Pull out the old lens S. Watanabe

2007/2/ Development of AVF in 2006 Glaser Lens (continued ) Beam focusing power is improved up to 2 times (F ∝ B 2 ) With New GLI38 With Old GLI38 Magnetic Field of Glaser Lens S. Watanabe Magnetic field (Gauss) Distance from medium plane GLI38 (Imax) GLI37 (Imax) Performance of GLI38 GLI37 GLI38 New / Old Main coil current (A) Glaser lens current (A)

2007/2/ Development of AVF in 2006 Beam Extraction Magnet channel and Deflector chips are improved. Extraction efficiency  is confirmed by using 14 N MeV/u. I 645 I 825  ~ 97% obtained  I 825 /I MeV/u, I ecr =17e  A, I 645 =4.1e  A, I 825 =4.0e  A I 825 ; after magnetic channel I 645 ; Before deflector entrance Goto/Kubono

2007/2/1116 Beam Extraction (continued) Transmission efficiency of ESD,  I 825 / I 645, is optimized by changing the Deflector Chip & Magnetic Channel to new one’s. The  of 97 % was then obtained when ECR current is 17 e  A *1. The ratio of A/  r N. in proportional to  is evaluated as follows. SFPSI TRIU MF AVF T e (MeV) 42 (p)590 (p)520 (p) ( 14 N 6+ ) R ext (m)  r N (mm) /3.07 *2  (  mm mrad) A (mm) /3.52* A/rNA/rN / n=number of Acc. Gap=4 V d = Dee voltage=45kV Table. Calculated A/  r N A = beam envelope at R ext,  r N = Turn separation at Rext *2=measured by main probe *1 Data; Nov. 28, 06 R&D, Dec. 11, 06 Exp. 8.2 MeV/u, I ecr =17e  A, I 645 =4.1e  A, I 825 =4.0e  A. Beam emittance,  ECR, of 110  mm mrad to be taken into account A/  r N., is derived from former Exp at E=6.4 MeV/u. Details of parameters

2007/2/ Upgrade of RIKEN/CNS AVF cyclotron - Subjects 1.TOSCA model construction Magnetic field calculation Electric field calculation 2. Study of Beam dynamics (examples) AVF beam dynamics modeling in the 3D E-map Bunch acceleration from the inflector exit to the final energy Optimization perspectives Transmission increase, beam quality improvement 3. Report / Proposal / Schedule Report to RIKEN/CNS from Accelerator group Proposal of New Inflector, RF shield, Dee chips for h=1, 3

2007/2/ TOSCA model construction AVF magnetic field ► Field at the surface are compared with measurements in the radial range 0-75cm. In the first stage, mesh model is generated from the drawings. In the second stage, corrective mesh model has been made on the basis of measurement. A.S. Vorozhtsov The optimizations of remaining differences in the simulations and measurements are still in progress.

2007/2/ TOSCA model construction AVF Electric Field Central region model Acceleration region model Number of nodes = 3.2 million. grid size in the very center is less than 1 mm A.S. Vorozhtsov

2007/2/ TOSCA model construction Acceleration region DC-E map R(150mm-750mm) A.S. Vorozhtsov

2007/2/ TOSCA model construction Central region DC-E map Rmax=149mm A.S. Vorozhtsov

2007/2/ Study of Beam Dynamics Confirmation of Inflector parameter and Trajectory B & E fields model are taken into account the beam dynamics calculation. Inflector (center), RF shield and Dee chips are shown. A.S. Vorozhtsov & A.S. Vorozhtsov & E.E. Perepelkin

2007/2/ Study of Beam Dynamics Confirmation of Acceleration parameter and Trajectory Injected bunched beam is accelerated along with reference orbits A.S. Vorozhtsov & E.E. Perepelkin

2007/2/ Study of Beam Dynamics Flat-top acceleration E.E. Perepelkin Expanded radial distribution FT OFF FT ON Narrowed radial distribution ESD

2007/2/ Report / Proposal /Schedule Resume of the RIKEN/CNS AVF cyclotron upgrade meeting is distributed to the meeting member. Presentations at the RIKEN/CNS AVF cyclotron upgrade meeting are distributed to the meeting member. Report on Study of h=2 acceleration will be published Following meeting will be held in August, 2007.

2007/2/1126 Summary Status of ECR Ion sources HyperECR, Metal IS, Super ECR, Charge breeder are advanced. Development of the AVF cyclotron Axial injection line is improved. Dee voltage and Extraction efficiency are improved. Upgrade of AVF cyclotron TOSCA model of AVF is completed, Beam dynamics model is advanced, Center region for h=1, 3 is to be proposed. Fine tuning of the TOSCA model is required. electrode, etc.