The RI Beams from the Tokai Radioactive Ion Accelerator Complex (TRIAC)

Transcription

1 The RI Beams from the Tokai Radioactive Ion Accelerator Complex (TRIAC)

2 Collaborator A. Osa, S. Abe, T. Asozu, S. Hanashima, T. Ishii, N. Ishizaki, H. Kabumoto, K. Kutsukake, M. Matsuda, M. Nakamura, T. Nakanoya, Y. Otokawa, H. Tayama, Y. Tsukihashi Japan Atomic Energy Agency (JAEA), Tokai, Japan S. Arai, H. Ishiyama, N. Imai, M. Okada, M. Oyaizu, S.C. Jeong, K. Niki, Y. Hirayama, Y. Fuchi, H. Miyatake, Y.X. Watanabe, High Energy Accelerator Research Organization (KEK), Tsukuba, Japan

3 JAEA-Tandem facility Tandem Accelerator V T =18MV (MODEL 20 UR) TRIAC 1.1MeV/u Superconducting Booster V acc =30MV Completion JAEA-Tandem Accelerator Aug Superconducting Booster Sep TRIAC Mar. 2005

4 Usage of beam times in FY2008 Cancel 11days/ 3.0% Maintenance (unscheduled) 7days/1.9% Maintenance (scheduled) 67days/ 18.4% Shutdown 55days/ 15.1% Operation 210days/ 57.5% Accelerator Development 19days/9.0% Radiation Effect 33days/15.7% Material Science 40days/19.0% Nuclear Physics 96days/45.7% Conditioning 15days/ 4.1% Nuclear Chemistry 22days/10.5% Operation of TRIAC: 23days Nuclear physics Material Science Accelerator development

5 Upgrade of JAEA-Tandem facility Performance of JAEA-Tandem Accelerator Terminal voltage Beam current limit (official license) 2.5~18MV H, D: 3 µa (>20 MeV), 10 µa(<20 MeV) Li, Be, B: 1 pµa Elements for Z 6 (C): 2 pµa Replacement of acceleration tubes Replacement of 180-degree analyzing magnet at the high-voltage terminal Replacement of in-terminal ion source to a permanent-magnet type 14.5 GHz ECR ion source, SUPERNANOGAN Treatment of degraded superconducting resonators Fabrication of a prototype low beta superconducting twin quarter wave resonator (low-β twin-qwr)

6 Upgrade of JAEA-Tandem Facility Replacement of acceleration tubes Initial performance of the maximum terminal voltage, V T =17MV, got worse for years. Replaced to compressed geometry tubes for the improvement of V T up to MV Ultrasonic Cleaning Remove micro-particles on the inside tube wall Reduce the conditioning time Original type 33gap/MV V T =18MV Compressed type 42gap/MV Replaced at Jun High-pressure Water-jet Rinse Compressed Air Ultrapure water Baking in vacuum 200 o C, 2 weeks Filled with N 2 gas to store

7 Upgrade of JAEA-Tandem Facility Recover of Superconducting Resonator The acceleration electric field (E acc ) of superconducting cavities decreases to 4MV/m. To remove small contaminations on the surface of niobium, treatment of superconducting resonators by using High-Pressure Water jet Rinse (HPWR) was carried out. Cavity Rotating nozzle Quality factor Q 0 Average E acc [MV/m] E in =4W with the age Year Effect of HPWR HPWR Water flow: 6 l/m, Pressure: 6~8 MPa E acc [MV/m]

8 Upgrade of JAEA-Tandem Facility Replacement of in-terminal ECRIS 14.5GHz ECRIS 180 o bending magnet Faraday cup Pre-acceleration tube 90 o injection magnet Turbo Molecular pump SUPERNANOGAN(2007~) Low Energy side Ion pump High Energy side Ion beam NANOGAN(1998~) HIAT 8 th Matsuda et al. (10GHz ECRIS) Electrostatic quadrupole triplet lens 14.5GHz ECRIS Aperture & Faraday cup 10GHz ECRIS Xe 30+ has been accelerated.

9 Tokai Radioactive Ion Accelerator Complex (TRIAC) Layout of TRIAC Tandem Accelerator: Primary beam Driver to ISOL Ion source RI production and ionization ISOL: RI separator and injector to TRIAC Booster Ion source ISOL CB-ECRIS: Charge-breed 1+ ion to q+ ion SCRFQ-linac: Accelerate to 0.17MeV/u IH-linac: Accelerate to 1.1MeV/u CB-ECRIS IH linac SCRFQ Experimental Apparatus H + 32MeV ~1µA 7 Li 3+ 64MeV ~200 pna Tandem Accelerator Primary beam from Tandem Accelerator Radioactive nuclear beam

10 JAEA-ISOL Primary beam Mass separation ISOL IS Danfysik 9000-T (ISOLDE type) Resolving power: 1200

11 JAEA-ISOL Safety Handling System of Target-Ion source Module Shielding cell Carrying system

12 Tokai Radioactive Ion Accelerator Complex (TRIAC) 18 GHz ECRIS as the charge breeder 1 + -ion from ISOL V acc =V CB micro wave: f=18 GHz, P=1 kw mirror coils: B max /B min ~1.5 /0.4 T movable deceleration electrodes correction coil: B max ~0.4 T sextupole magnet: length=300mm φ in =82.5 mm B max ~1.1 T at 75mm φ q + -ion V CB =2 A/q kv to SCRFQ

13 Tokai Radioactive Ion Accelerator Complex (TRIAC) Performance of Linacs SCRFQ Split-coaxial-RFQ (SCRFQ) linac Very compact (diameter = 0.9m) RF frequency 25.96MHz Input energy 2.1keV/u Output energy 178kev/u (A/q 28) Transmission >90% Vane length 8.6m Inter-digital H (IH) linac 4 cavity tanks, 3 magnetic-quadrupole triplets RF frequency 51.92MHz Input energy 178keV/u Output energy MeV/u (A/q 9) Total length 5.6m Total transmission of two linacs ~85% Duty factor 20% 100% Beam IH-linac Beam

14 Development of Target-Ion Source System Schematic view of Target-Ion Source systems Filament-2 Ionizer Radioactive ion beam Thin foil Filament-1 Proton beam UC x target Heat shields Target container T=2100 o C Uranium Target-Surface Ionization IS Radioactive ion beam 2 4 Anode with grid Gas inlet Outlet Electrode 3 Connection connection pipe pipe Proton beam EB heat cathode 1 target container with heater Target container with heater UC x target T=1600 o C Uranium Target-FEBIAD-B2 IS Alkali, alkaline earth, and rare-earth elements Gaseous and volatile elements We could not observe short-lived isotopes of In, Sn.

15 Development of Target-Ion Source System Outlooks U-FEBAID-E Ion Source U-FEBIAD-B2 (1600 o C) Separation efficiencies were miserably decreased for short-lived isotopes. We could not observe short-lived isotpes of In, Sn FEBIAD-E + Target container (>2000ºC) Short release time is expected. 3 2 Anode with grid Outlet Electrode 4 Gas inlet 1 EB heat cathode Radioactive ion beam connection Connection pipe pipe Target target container container Filament filament Proton beam from tandem accelerator On-line test is in progress.

16 Development of Target-Ion Source System Surface Ionization IS for Heavy ion reaction 99% enriched 13 C sintered pellet target 7 Li W-window Measurement of Li diffusion coefficients in Li ionic conductors Search of highly excited state of 10 Be using deuteron elastic reaction 8 Li to 8 Li Search of highly excited state of 11 Be using deuteron elastic reaction 13 C( 7 Li, 8 Li) to 9 Li 7 Li 3+ beam 67MeV ~100 pna 1 x 10 6 ions/s 9 Li(T 1/2 =178 ms) ~10 2 pps Request: >5 x 10 3 pps Increase a target weight Increase a beam energy/current Increase a release speed?

17 Development of Target-Ion Source System Release profile of Li Current/arb. unit 10-1 Release profile of Li by Heavy ion implantation technique C sintered pellet fast =3.2 s BN Hot pressesd sheet fast =120 ms Time/s Separation yield of 8 Li/ 9 Li A 99% enriched 13 C sintered pellet target 8 Li: ~ Li 9 Li: ~10 2 ions 7 Li BN Hot pressed sheet target 8 Li: ~ Li 9 Li: ~ Li

18 OUTLOOK Continuous upgrade enabled JAEA-Tandem facility to deliver a variety beams for experiments. Until now, TRIAC facility provides relatively weak intensity and low energy RNBs. However, we have produced good results by using 8 Li beam which is specialty of TRAIC facility. It is expected to allow further applications and progresses especially by use of the RNBs of mediumheavy neutron-rich isotopes. Development of the target-ion source system is one of the highest priority issues on operation of RNB facility. We will carry on the development for the facility.

19 Appendix

20 Development of devices for In-terminal ECR-IS Installation environment High-pressure SF 6 : 0.44 MPa High-voltage spark Limited supply capability Limited space Countermeasure against High-pressure SF 6 Ion source RF power supply Devices Surge-protected designing of Control system and devices Optimization and simplification of parameters for stable operation Construction of maintenance-free and fail-safe system TMP Vacuum system under High-pressure SF 6 matsuda.makoto@jaea.go.jp

21 Examples of countermeasure Broken ADC by High-pressure After countermeasure RF power supply assembled in pressure-resistant container

22 Leakage test by QMS Leakage test by QMS at the high-pressure test bench.

23 Upgrade of control system Broken FET by surge Multi-channel control module with optical communication

24 TMP Vacuum system Layout of terminal devices 180 bending magnet M/ M=140, ME/q 2 =55 EQT ES 0kV potential (terminal) 80kV potential 110kV potential (source) EQT : electrostatic quadrupole triplet ES : electrostatic steerer FC : faraday cup VA : variable aperture IP : ion sputter pump FC pre-acceleration tube 90 injection magnet Einzel lens & ES(x) 10GHz ECRIS cold cathode gauge turbo molecular pump IP IP FC EQT foil stripper IP FC & VA IP vacuum pertition valve rotary pump exhaust gas accumulator vessel low energy main acceleration tube IP high energy main acceleration tube Pressure tightened RP side view matsuda.makoto@jaea.go.jp front view

25 Reduce of leakage field ECR-IS by strong permanent magnet Leakage field (2 line) bent ion beam!! For the safety of maintenance with machine tools Without Shield With Shield Al frame +Al panels +Fe panels

26 Upgrade of JAEA-Tandem Facility Replacement of in-terminal ECRIS 14.5GHz ECRIS 180 o bending magnet Faraday cup Pre-acceleration tube 90 o injection magnet Turbo Molecular pump SUPERNANOGAN(2007~) Low Energy side Ion pump High Energy side Ion beam NANOGAN(1998~) HIAT 8 th Matsuda et al. (10GHz ECRIS) Electrostatic quadrupole triplet lens 14.5GHz ECRIS Aperture & Faraday cup 10GHz ECRIS Xe 30+ has been accelerated.

27 In-terminal ECRIS: SUPERNANOGAN Acceleration results and performance