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Present status of search for francium EDM Detector Group, CYRIC, Tohoku University Hirokazu Kawamura H.P. Yoshida. CYRIC Tohoku Univ., Univ. of Tokyo, Tokyo Univ. Agri. Tech., RCNP Osaka Univ., Kyoto Univ., Tohoku Univ., Tokyo Inst. Tech., Kyusyu Univ., contents Introduction CYRIC new ECRIS Swinger magnet Setup Surface Ionizer Beam Transport Neutralizer Laser trapping Research Plan K. Hatanaka,A. Hatakeyama,T. Aoki, K. Harada,T. Hayamizu,K. Imai, M. Itoh,H. Kawamura,T. Murakami, A. Oikawa, Y. Sakemi Y. Sakemi,M. Saito, T. Sato,T. Shimizu,M. Uchida, T. Wakasa,
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Atomic beam Laser cooled/trapped atom High precision measurement in laser cooled/trapped 210 Fr Heaviest Alkali Atom = 210 Fr : Large Enhancement Factor Cooling & Trapping Long Coherence Time Precision x 600 ~ Next Generation EDM Search MOT Laser 1 nK 1 K 1 K1 mK1000 K Room temp. Liq 4 He Liq 3 He Laser cooling Evaporation cooling temperature BEC FD Francium: Laser cooling to a few K and trapping. → Very long interaction time! Improve measurement precision! 210 Fr 205 Tl 1150 K : Enhancement factor 585 ~10 2 sec : Coherence time ~10 -3 sec 3.2 min T : Lifetime Stable ~ 10 -28 d e : EDM (e cm) ~10 -27 World record E.D. Commins et al, 2002 EDM search ~ Laser trap
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High Intensity Laser Cooled Francium Factory at CYRIC 18 O beam Beam Swinger 197 Au target Surface Ionizer 210 Fr + ion Beam Transport/ Diagnosis System Neutralizer 210 Fr atom Zeeman Cooling Magneto-Optical Trap Cooled 210 Fr AVF Cyclotron Primary beam: 100MeV 18 O 5+ Production: 18 O+ 197 Au→ 210 Fr+5n 708090100 Beam Energy [MeV] 100 10 [mb] 209-210 Fr product. cross section 1
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New ECR Ion Source 18 O beamNew ECRIS: >2euA (next step), Old ECRIS: 100enA 10 GHz ECRIS 2008/July: Move from RIKEN ~ Request: Heavier Nuclide & Higher Energy 2009/May: Test start 2009/July: First acceleration 2009/July: Shutdown for Renovation -- 2010/March 2010/June: First Run for Experiment Swinger magnet 2010/May: Swinger fixed @ 45 deg. 2010/May– Test Run, Performance Check
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count 210 Fr (6.543MeV) 206 At (5.703MeV) Measured alpha-ray pectrum Surface Ionizer-I 18 O beam Fr + ion 197 Au target CYRIC group LNL (Italy) 1.4x10 7 atom/s Extraction efficiency Extracted 210 Fr 8x10 6 atom/s Produced 210 Fr in Au target 3x10 6 atom/s 4.1x10 4 atom/s 40% 0.29% Calculation Measurement 50-200um thick gold electroplating on Ni-mount Stancari, NIMA594(2008)321
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45 deg incident Swinger magnet Surface ionizer Rb beam Fr ion Surface Ionizer-II Stable Rb beam Fr ion Oven (W) 197 Au target (1000 deg C) 1mm thick gold plate Einzel lens Extraction electrode Target rod (W) 18 O beam 45 deg. Incident Prevent gold from flowing out. Vertical Fr extraction from Au target Yield increase. SiC heater + target cooler maintain temperature (oven 1500 deg C, target 1000 deg C) Port for stable Rb beam Offline test. Aim for:Fr + yield > 10 6 pps, Extraction efficiency > 10% 18 O beam (Ionizer-I: ~0.1%) Production: 18 O+ 197 Au→ 210 Fr+5n
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collimate Au target extraction 18 O beam TOSCA Simulation Electric field; Finite Element Method Offline Test Surface ionizer-II Vacuum test Heating test Voltage apply test Rb oven (Rb atom beam source) Rb ion beam first observed at viewer on July 6 Surface Ionizer-II
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Fr Beam Transport Ion Optics (UeGios) 1.High Transport Efficiency (~100%) 2.Focused Beam (φ5mm) @ Neutralizer 3.Extreme High Vacuum : Differential Pumping 10 -6 to 10 -9 Torr 4.Beam Diagnosis/Monitor System Requirement Beam line Overview
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Deflection electrode Steering Cable port Alignment Laser & Radiation Thermometer Alignment Laser SSD Electrode Under construction @ KT Science Ltd. To be installed in August 2010.
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Q-electrode After Baking (130V), Simple Vacuum Test We achieved 10 -9 Torr ! ~ 1 week Electrostatic Quadrupole Triplets TOSCA (FEM) YZ XZ SiO2 duct Reduce outgas from electrodes
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Neutralizer Yttrium catcher Charge exchange with Alkali vapor Ion-Electron Recombination 1.Focused beam high efficiency 2.Low energy laser cooling 3.Ultrahigh vacuum laser trapping Y ~ E WF (3.1eV) < E IP (4.1eV) → Fr atom Li + + Na Li + Na + @ TRIUMF-ISAC Fr + + e - Fr + hν Fr + ion ~ keVFr atom Laser Focus ~ 700 mm Deceleration ~ eV Focuse-gun Fr + + Rb Fr + Rb + @ SUNY Which has a higher neutralization efficiency? @ many laboratories! Zeeman slower, MOT chamber.
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e-gun type Neutralizer TOSCA (FEM) Rb beam test is currently in progress in Japan! Very low recombination cross section? Need to make energy very low? Offline setup Neutralizer
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Laser lab. F=2 F=1 6.834 GHz F=3 F=2 F=1 F=0 267 MHz 157 MHz 72 MHz 5 2 P 3/2 5 2 S 1/2 780 nm Repumping Cooling 87 Rb 795 nm F=13/2 F=11/2 46.768 GHz F=15/2 F=13/2 F=11/2 F= 9/2 617 MHz 500 MHz 397 MHz 7 2 P 3/2 7 2 S 1/2 718 nm Repumping Cooling F=13/2 F=11/2 7 2 P 1/2 817 nm 210 Fr 6149 MHz Verdi + MBR110(Ti:S Laser) to be installed in July/23 ECLD + Taper amp. 718nm 780nm COHERENT
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Laser lab. Optical fiber (150m) MOT Neutron Flight Path Cooled Francium Beamline Renovation Clean room Design … Zeeman slower, MOT chamber Fr + ion Q-electrode Neutralizer slower Zeeman slower MOT chamber
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Research Plan 2010/JulyOnline test -- Surface Ionizer + Beam Transport + Neutralizer 2010 High-intensity Fr-ion beam 2011 High-intensity neutral Fr atom + MOT -- Complete Laser-Cooled Francium Facility 2012 Start EDM measurement 2013 Establish precision EDM measurement -- Aim for World Record d e < 10 -28 e cm Fr + extraction yield: 10 6 cpsFr 0 trap: 10 6 atoms
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Experimental setup for surface ionizer-I 197 Au 18 O 5 + Beam 241 Am (for SSD source test) Fr + 460mm Surface ionizer 874mm SSD Triplet-Q electrodeExtraction setup Surface ionizer Beam transport system SSD holder @CYRIC course-34 Primary beam line SSD: detect alpha particle from Fr on its surface.
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Surface ionizer-II / Heating test Cathode Shroud
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For Ultrahigh Vacuum of Beam Transport System TMP Pressure [Torr] 10 -5 10 -6 10 -7 10 -8 10 -9 Surface IonizerNeutralizer Calculation of Vacuum 200 150 100 0 50 Temperature [deg. C] Q-electrode Heating Test 900mm 400L/s *3
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20 Yttrium catcher neutralizer 18 O beam Au target Y target Fr ion Fr atom to Trap Surface IonizerNeutralizer Target : Gold (Au) ~ E WF (5.1eV)>E IP (4.1eV) → Fr + ion Target : Yttrium (Y) ~ E WF (3.1eV)<E IP (4.1eV) → Fr atom Y target Fr ion Fr atom Heating (~1000K) Neutralized Fr atom is diffused. 20 Oven (Y) temperature : 1000 K ~ heater temperature for Fr atom release Capturing velocity of MOT : Vc~1 m/s Fraction of trapping atoms : 10 -4 ~ 10 -5 High trapping efficiency realization ~ need to cool atoms v Fr ~281 m/s, v rms ~345 m/s v Rb ~333 m/s, v rms ~408 m/s
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Ionization/Recombination constant Oxygen Ne Ar Na 1eV1keV 1eV 1keV 1eV 1keV 1eV1keV Ionization Recombination (rare gas) (Alkali metal) Omegatron (user) has succeeded in the neutralization of Ar (O).
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10 12 atoms/sec Equivalent energy ~ 20-30eV target Heating holder Atoms soft-landing on target thin-film produced Ion accel. 1000eV VDS ~80eV anode O2O2 Electron bombard type Discharge chamber Extract. electrode 1 st focus lens2 nd focus lensDecel. lens Neutralizer target Application of deceleration-type slow-neutral beam generator to thin-film (Nitride or Oxidize film) production http://www.omegatron.co.jp Valid gas … O, N, Ar and rare gas
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Neutralization using Alkali vapor TRIUMF-ISAC Na vapor density ~ 10 14 atom/cm 2 Neutralization efficiency ~ 95% Vacuum pressure ~ 2x10 -7 Torr (= 3x10 -5 Pa) 8Li energy ~ 30keV SUNY (Sprouse) Rb vapor density ~ 5x10 13 atom/cm 3 Neutralization efficiency >80% 210Fr energy ~ 5keV 5keV | 10keV | 1keV | Rb + energy Fr + -Rb 0eV | Perel,Phys.Rev.138(1965)A937 Cs + -Rb Rb + -Cs Cs + -Cs Rb + -Rb
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LD TA EDLDGrating Trap Laser Optical fiber (~150m) Laser cooling MOT Laser Trap Sr cooling/trap system Neutral Fr atom TOF tunnel Laser room : non-radiation controlled area Fr cooling/MOT/ Laser Trap Sr cooling/MOT Laser for RbLaser for FrLaser for Sr Laser transport “Science trap” Next generation EDM search: … Fr-Sr Ultraslow polar molecule at Feshbach resonance
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