In-Flight Fragment Separator and ISOL Cyclotron for RISP

Transcription

1 In-Flight Fragment Separator and ISOL Cyclotron for RISP Jong-Won Kim Daejeon, May 9, 2012

2 Scope of Presentation in the RI Science Project

3 Area of the IF Separator and ISOL cyclotron Two kinds of beam lines: High-intensity, low-intensity Radio Chemical Lab. Hot cells, etc. à Under discussion with Radiochemist and medical scientist In extracting 1 ma H - beam, lifetime of C foil is an issue: ~ < 1 hr for 1 ma (?)

4 A layout of a fragment separator for RISP Hot zone, 400 kw beam dump A layout from the design study ended in Jan. 2011

5 Design of In-flight Fragment Separator Pre-separator: S-shape Main separator: C-shape Pre-separator is more concerned to handle high-power beams. 2-dipole C-shape pre-separator W. Wan, J. Kim, Cyclotron Conf Max. magnetic rigidity= 8 T m

6 Horizontal Optics of different shape pre-separators S-shape Beam dump Shielding Wedge 2-dipole C-shape Vertical Dp/p= 1.5% Aberrations up to 7 th order Difficult in placing localized beam dump, shielding and the wedge

7 Optics of the 4-dipole C-shape pre-separator Horizontal Beam dump Shielding wall Wedge Vertical Dp/p= 0.1% Dp/p= 1.5%

8 Magnet parameters for the S-shape preseparator Type Length (m) Pole tip radius (m) Field at pole tip (T) Quad Quad Quad Dipole 30 degrees Quad Quad Quad Sextupole Sextupole Quad Quad Quad Dipole 30 degrees Quad Quad Quad Beam optics calculation using COSY Infinity performed by Dr. W. Wan of LBL angular acceptances: 80 mrad, 100 mrad momentum acceptance : 18 % for r=20 cm, 9 % for r= 15 cm length: 24.8 m

9 Result of high-order correction for the main separator Dp/p = ±5 % Without correction With sextupole+octupole corrections

10 Preliminary design of a quadrupole magnet for prototyping Design of quadrupole magnet - Pole tip radius: 170 mm - Length of iron: 740 mm - Outer radius of yoke: 480 mm - Blend radius of pole edge: 12 mm Distribution of multipole components (r=120 mm) - 12-pole component(n=6) is about 1/100 of quadrupole component(n=2) - Field integral is about 1/1000 Do-gyun Kim

11 Prototyping of a cryostat Prototype of quadrupole triplet - Compact cryostat using two small cryocoolers is considered. - High Tc current lead will be used to reduce the heat load. - Multipole coils will be employed inside the quadrupole magnet. Estimation of heat loads of cryostat Part Heat load (He, 4K) Heat load (N2, 80K) Shield radiation 0.30 W 9.4 W Support link 0.64 W 16.0 W He port (vent) 0.77 W 7.8 W Current lead 0.75 W 45.0 W Total 2.46 W 78.2 W Schematic diagram of the prototype quadrupole triplet Do-gyun Kim

12 Heat deposit calculation using PHITS 7cm 10cm Heat at rotating target ( 12 C) Elements Heat max [J/cm3] Dose rate [Gy/yr] * Dose rate (MSU # ) Coll. & Q * *10 7 Colli. & Q1 Q2 Q3 Beam dump Q * *10 6 Q * *10 6 Beam dump DCHAIN-SP, (activation), ANSYS (Heat transfer, structural analysis) *10 12 # dose rate calculated using 400MeV/u 238 U beam at 400kW and 9 Be target

13 Design of an rf deflector to purify rare isotope beams A filtering option to purify proton-rich rare isotope beams à rf deflector Frequency= 70.5 MHz Q=11400 V=100 kv at 7.1 kw 3D modeling and E-field distribution calculated along the electrodes RIKEN, Japan

14 An RF deflector system to measure the bunch length of a low-energy ion beam Development of an rf deflector for bunch length monitor Argonne, ATLAS f=97 MHz 93 MHz, designed for cw proton cyclotron, h=4 J. -Y Kim et al., Linac 2010 Schematics of the cw bunch length measurement

15 An LLRF system developed for the rf deflector Stability req. Phase: < ±1 Amplitude: < ±1% Circuit diagram and a picture of the LLRF LLRF Full-scale model rf deflector Vibration system C. Hwang, Korea Atomic Energy Research Institute

16 Tests of the LLRF system Control signals for the perturbations by a plastic rod attached to audio speaker (Top) Control signal for the amplitude for the perturbation, (Bottom) for the phase.

17 A cw heavy-ion beam line for tests of beam diagnostics devices Sawtooth wave rf buncher Moving Slit Wire Faraday cup Beam measurement box Colutron Inc. Ion source D. Kim, J. Kim, Proc. IPAC 2011 J. Kim, D. Kim, JINST 2011 e rms = ~5 pmm mrad 12 C +, at 15 kv extraction Bunched beam measurement

18 Main Specification of the ISOL cyclotron Specification: H - cyclotron, 70 MeV, 1 ma max. Pulse neutron beam Pulsed proton (neutron) beams for nuclear data measurements L Neutron Target Sample Detector Fast chopping by N for pulsed beams L (m) En (MeV) T (ms) N Proton beam Electron Beam Time structure (Pulse) Time Neutron Beam

19 Construction or purchase of the cyclotron Domestic capability A 30-MeV, H - cyclotron has been constructed. Manpower for R&D on the 70 MeV cyclotron is not sufficient. Magnet 30 MeV Cyclotron inside Commercial cyclotron vendors Sumitomo Heavy Industry, Japan 70 MeV, 1 ma, H - Best Cyclotron Systems, USA 70 MeV, 1 ma, H - IBA, Belgium 70 MeV, ~750 ma, H -, d, a in operation

20 Review for domestic construction Comparison of cyclotron parameters with those of 70 MeV commercial cyclotron Parameters 30 MeV Domestic 70 MeV (Team BEST*) B 1.05 T 0.95 T f MHz 58 MHz h 4 4 R ext 0.72 m 1.1 m B max 1.9 T 1.6 T W 50 tons 195 tons * V. Sabaiduc et al., Proc of Cyclotron Conf Magnet design with a larger vertical gap Higher power rf system New injection beam line à Technically feasible but need more dedicated manpower.

21 Neutron #/cm 2 per proton msv/y Shielding wall calculation using MCNPX Concrete(2.3g/cm 3 ) 1mA,70MeV proton beam copper neutron Generated neutron energy dis. E n (MeV) Dose equivalent rates Assuming 5000h/y operation Concrete thickness[m] By M. Kim

22 Items for comments and suggestions Comments on the pre-separator design. Comments on the 70 MeV cyclotron Suggestions on the potential items for international collaborations. We plan to prototype a superferric magnet with a large aperture and cryostat with a quadrupole triplet., à Construct the scmagnets with domestic companies.

23 Potential items for international collaborations. High Tc Sc-quadrupole at the front end of IF separator for FRIB Multi-layer IF targets Modular beam dump