RCNP cyclotron facility

Transcription

1 11th International Conference on HEAVY ION ACCELERATOR TECHNOLOGY RCNP cyclotron facility K. Hatanaka Research Center for Nuclear Physics Osaka University HIAT09 TU9 June 9, 2009 Venice (Italy)

2 Outline 1. Overview of the RCNP facility 2. FLAT-TOP acceleration by the AVF cyclotron GHz ECR ion source 4. Some results with heavy ion beams γ-decay of high-spin isomers Production of 210 Fr for electron EDM search 5. Summary

3 Research Center for Nuclear Physics, Osaka University Cyclotron Laboratory : Nucleon, Meson, Hadron Physics AVF cyclotron with K=0.14 GeV and Ring cyclotron with K=0.4 GeV Polarized p,d & light heavy ion with Ep=0.01 ~ 0.4 GeV, E/A=0.01 ~ 0.1 GeV Laser Electron Photon Laboratory : Quark Nuclear Physics 1 ~ 3.5 GeV Polarized Photon Beams by Back Scattering of Laser Photons (2 ~ 6 ev) from 8 GeV electrons at Spring-8 Ohto Cosmo Observatory : Lepton Nuclear Physics Underground laboratory with low background (500 m depth, 10 Bq/m 3 Rn & 4*10-3 /m 2 /s cosmic μ Double b-decay, Dark matter search, etc. West Harima, Spring8, Hyogo Suita, Osaka Tentsuji-tunnel in Ohto, Nara

4 RCNP Cyclotron Facility Ring Cyclotron Lab. Main Bld. RI Lab. AVF Cyclotron Lab.

5 Neutron polarimeter RI beam R I Ring Cyclotron K=400 MeV since 1992 ΔE/E ~ 0.01% 10ucn/cc at 90neV (with 400W proton) Double Arm Spectrometer White Neutron Source AVF Cyclotron K=140 MeV since 1973 ΔE/E < 0.1% Energy Resolution ΔE/E ~ 0.005% RI production RI Upgraded recently

6 after the upgrade of AVF in 2004

7 Operating statistics Hours AVF cyclotron was commissioned Ring cyclotron was commissioned Developments were started to increase the intensity of HI beams

8 Operating statistics in 2007 Ion species Pol-D 42h 57min Total : 6100 hours 11-B 113h 43min Pol-P 606h 03min 15-N 357h 07min 40-Ar 108h 20min 86-Kr 383h 06min Proton 2630h 15min 16-O 237h 17min 18-O 54h 30min 6-Li 193h 42min 4-He 518h 47min 3-He 517h 54min Deuteron 337h 10min L. I. (P ~ He) : 4653 h H. I. (Li ~) : 1447 h

9 RCNP K140 AVF Cyclotron Magnet Pole diameter Pole gap Averaged field Trim coils Valley coils Weight : 3.3 m : 20.6 cm ~ 34.7 cm : 1.6 T : 16 sets : 3 ~ 5 sets : 400 tons Acceleration system Dee : Single 180 degrees type Resonator : Moving short Frequency : 6 ~ 18 MHz Max. acceleration voltage : 80 kv Extraction system: Electrostatic deflector FT system (k=5,7,9) Ion Sources External ion source : Atomic beam type polarized ion source, ECR ion source 18 GHz SCECR ion source

10 RCNP K=400 Ring Cyclotron Magnet Sector magnets Pole gap Maximum magnetic field Trim coils Injection radius Extraction radius Weight Acceleration system Single gap type Frequency Max. acceleration voltage RF power Flat-top cavity Single gap type Frequency : 6 sets : 6 cm : 1.75 T : 36 sets : 2 m : 4 m : 2200 tons : 3 sets : 30 ~ 52 MHz : 500 kv : 250 kw/cavity : 1 set : 90 ~ 156 MHz Key element for high quality beam World first FT system operating at variable frequencies

11 3 rd harmonics First harmonics

12 Voltage Waveform of Fundamental and FT acceleration Using 3rd, 5th, 7th and 9th Harmonic Frequencies 0 ΔE = V 1 +V 3-2x10-4 o Δφ = ± 0.6 ΔV/V -4x10-4 Δφ Ring o = ± 6.2 V 1 +V 5-6x10-4 V 1 +V 7-8x10-4 V 1-1x E k cos cos k k 1 = 2 E k Δ φ φ + RF Phase (degrees) V 1 +V 9

13 FT systems for the AVF cyclotron Characteristics Harmonic frequency : 50 ~ 80 MHz Harmonics : k = 5, 7, 9 Flat-top cavity Outer tube:φ170 mm Length: 700 mm Layout of RF system Capacitively coupled to the main resonator Dee voltage pickup New Dee electrode with a 10 mm wide and 1 m long slot

14 Modification of the Dee Electrode to avoid the interference by the parasitic resonance mode near 80 MHz generated in the transversal direction of the dee electrode E p = 300 MeV New Dee electrode with a 10 mm wide and 1 m long slot 100 Frequency 共振周波数 (MHz) (MHz) th 5*f harmonics Dee Dee 3λ/4 3/4λ mode 並列 eモード並列 dモード Dee transverse Dee 横モード mode Dee λ/4 1/4λ(f) mode Position 主ショート板位置 of the shorting (m) plate (m)

15 Dee Voltage Pickup Dee-voltage pickup electrode Example of the pickup voltage waveform 87MeV 4He2+ f 1 = MHz f 5 = MHz 4 electrodes Dee Voltage Waveform for FT Acceleration of 87 MeV 4 He 2+ facing the Dee electorode, placed near the acceleration gap, used for regulation of RF system. Voltage (mv) RF Phase (degrees)

16 18 GHz Superconducting ECR Ion Source Highly charged heavy ions A variety of heavy ions at high intensity 800 eμa 18 O 6+ beam with RF power of 600 W

17 Plasma Chamber Plasma Chamber: Φ80x380L 1800cm 3 SC Coil Al liner of 1 mm in thickness inside of plasma chamber RF Einzel Lens Gas Extraction Electrode Hexapole NEOMAX-44H : Φ90(inside) Bias Probe Cooling Water Al Al disk ~1T on the chamber wall

18 Ion Currents (eμa) * Optimized for these ions RF 11 B ( 4 He) * W 12 C (CH4) ( 4 He) * W 15 N ( 4 He) * W 16 O ( 4 He) * W 18 O ( 4 He) * W Ar ( 16 O) * W Kr ( 16 O) * W Xe ( 16 O) * W comparable ion beams from NEOMAFIOS N O MIVOC Method with o-carborane (C 2 B 10 H 12 ) Bean intensity is increased by one order of magnitude compared to the existing NEOMAFIOS. Highly charged ions become available for heavier elements.

19 Bypass Bypass & & diagnostic diagnostic beam beam line line Object point Object point Emittance monitor: Profile Emittance measurement monitor: Profile measurement Emittance monitor: Slit Emittance monitor: Slit Vertical Imaging Vertical point Imaging point

20 Bypass Bypass & & diagnostic diagnostic beam beam line line Profile monitor Emittance Slit Achromatic Transport Horizontal Object point Object point Emittance monitor: Profile Emittance measurement monitor: Profile measurement Focal Plane Emittance monitor: Slit Emittance monitor: Slit Vertical Vertical Imaging Vertical point Imaging point

21 EN (Exotic Nucleus) beam line RCNP secondary beam line D1 SX1 F1 SX2 Q4 D2 F0 Q1 Q2Q3 Q5 Q6Q7 SX3 F2 T. Shimoda et al., NIM B70 (1992) 320. S. Mitsuoka et al., NIM A372 (1996) 489. Maximum rigidity 3.2 Tm Energy acceptance ΔE/E =16% Angular Acceptance Δθ = 40 mrad Δφ =28 mrad Path length 16.8 m

22 RCNP Ge array 14 Ge det. total efficiency 1.9 % at 1.3 MeV 14 Ge + 6 BGOACS total efficiency 1.0 % at 1.3 MeV Ge det. : Dep. of Phys. & RCNP Osaka Univ., Dep. of Phys. Tohoku Univ., SUNY

23 search for high-spin shape isomers in N=83 isotones 17 N RI beam fusion reaction primary reaction : 9 Be( 18 O, 17 N) 10 B 9.2 MeV/u, 0.8 pμa secondary reaction : 130 Te + 17 N 5.0 MeV/u, ~10 5 pps Gamma-rays by secondary fusion reaction were observed. counts preliminary result projection spectrum of γγ coincidence Te ( 17 N, 4n ) 141 Pr 130 Te ( 17 N, 5n ) 142 Pr gamma-ray energy [kev]

24 Oven target and surface ionizer to produce 210 Fr for e-edm measurement F r 18 O MeV 1 pμa 197 Au 50 μm

25 Target rod Thermocouple 10φ 50μm Au Oven beam Thermal sheilds Extraction electrode 29.75mmφ

26 14mm beam beam Surface ionizer

27 Spectrum of α-particles (log scale) 209 Fr 6.646MeV (T 1/2 59.1sec) 210 Fr 6.543MeV (T 1/2 191sec) 205 At 5.902MeV (T 1/2 26.2m) atoms/sec/3eμa 206 At 5.703MeV (T 1/2 30m)

28 Summary The RCNP cyclotron facility provides a variety of ion beams in a wide energy region. Developments are in progress to increase research opportunities. FT system SCECR ion source Optimization of the central region to improve the transmission through the AVF cyclotron. Thank you for your attention