Search for permanent electric dipole moment in Francium ~ present status ~
Yasuhiro SAKEMI
Cyclotron and Radioisotope Center, Tohoku University
１．Background２．EDM measurement using cooled radioactive atoms３．Development of experimental apparatus４．Summary
Physics motivationUnderstanding the baryon asymmetry in the Universe → requires extra CP-violation
Search for the phenomena beyond the standard model ~ EDM
Jr
dr T
J−r
dr CPT ~ No evidence of violation
T: Time Reversal ~ No clear evidence of violation CP: violation was found ~ K0, B decayCPT theorem + CP violation → T violation ?
e EDM from standard model : 3 loop diagram with de = 1 loop-diagram ~ no EDM + 2 loop ~ no EDM + gluonic correction
+ +e
e
γ
e
e
eL eL
eR eR
ν
W
Wf
f
f
b
bb
eR
eL
W
W W
uj
dj
Lowest order where EDM appears Estimation ~ 10-37 e・cm
Electric Dipole Moment : EDM
Some EDM measurements
EDM Experiments WorldwideSystems where EDM have been looked at are fundamental particles, atoms and molecules
11 orders of magnitude larger than the Standard Model prediction. ⇒ small BG
Theoretical prediction
de(Standard Model)<10-37
⇒ No background of the contribution from the standard model
EDM Measurement and Sensitivity
EdhEdBhEdBh
⋅=Δ⇒
⋅−⋅=
⋅+⋅=
↑↓
↑↑
42222
νμνμνE E
Electric dipole moment : d
System containing EDM
K×deAmplified !Example: d=10-25 e cm, E=10 kV/cm, ωe = 10-6 Hz
TNEKehd
⋅⋅⋅⋅⋅=
τδ 111
2Sensitivity
Enhancement of e EDMusing high Z atom
High Intensity Surface Ionizer Laser cooling
Elongate preservation time of polarization using MOT
Polar molecule produced through Feshbach Resonance
EDM search ~ Francium atom
Le~
γ
e e
Re~
bino
Le~
γ
e e
Re~
binoelectron
SUSY particle
Fredr
Electron EDM ~ Require mechanism for amplifying weak signal ~ Atom
eFr ddrr
×=1150
20
25223 )0(~~~aeVZZ
ddK s
e
atom αψα
Enhancement factor
0
200
400
600
800
1000
1200
1400
0 20 40 60 80 100
K
Char
ge :
Z
Enhancement factor simple
Rb Xe Cs
Tl
Fr
Enh
ance
men
t fac
tor
Francium：Alkali metal with largest atomic number ~ RIEnhancement of electron EDM ~ largestAtomic structure ~ Simple
Previous method using atomic beamNewly proposed method210Fr Tl（world record）
1150 K：Enhancement Factor
585
~102 sec τ： coherence time ~10-3 sec
>10-28 EDM (e・cm) ~10-27
Production of 210Fr via nuclear reaction.Laser cooling and trap of 210Fr..Enhance detection sensitivity more than factor of 600.
MOT
EDM search ~ Laser trap
Laser
1 nK 1 μK 1 K1 mK 1000 KRoom temp.Liq.4HeLiq. 3He
Laser coolingevaporative cooling
Temperature
BECFD
Cool down 210Fr to several μK using laser cooling, then trap it→ realize long interaction time to achieve higher detection sensitivity
Laser cooled Francium Factory
Francium production
18O+197Au Fr production
0.01
0.1
1
10
100
1000
50 70 90 110 130
beam energy (MeV)
Cro
ss s
ecti
on (
mb)
212Fr 211Fr 210Fr 209Fr 208Fr
18O+197Au
19F+198Pt Fr production
0.01
0.1
1
10
100
1000
50 70 90 110 130
Beam Energy
Cro
ss S
ection (
mB
)
212Fr 211Fr 210Fr
19F+198Pt
210Fr ~ 3min.
212Fr ~ 18 min.
Fusion Reaction :Statistical model calculation
18O + 197Au → 207-211Fr + Xn
⎟⎠⎞
⎜⎝⎛ −
=+
kTEE
nn IPWFexp
21
0
Target : Au ~ EWF(5.1eV)>EIP(3.8eV) → Fr+ Ion
Production ratio between ions and neutral atoms:
EWF:: Work functionEIP： Ionization potential
FrRn
At
Po
Bi
209 210 211
206 207 208
209 210
207 208
204 205 206
Ionization Potential (eV)
3.83
10.748
9.65
8.43
7.289
Target rod
Oven
Gold target
Outer reflection electrode
Inner reflectionelectrode
Fr+ Fr+ Fr+Fr+
9cm
Heat reflector
Extractionelectrode
Surface Ionizer
Structure of oven:Adjusting the size of extraction electrode to confine Fr produced by fusion reaction and reduce emittance of beam.
18O + 197Au → 207-211Fr + Xn
Beam emittance～２０πmm・mrad
Surface Ionizer for Fr production
Extraction efficiency of 210Fr ~ 0.29% ( ~ 30% by LNL/Italy)
Fr produced in gold targetExtraction efficiency(%) =Extracted Fr
×100
coun
t
coun
t
210Fr (6.543MeV)
206At(5.703MeV)
210Fr(6.543MeV)
Results ~ present status
Yield of 210Fr ~ 4.1×104 atoms/sec
Fr yield ~104 Fr+/sec achieved ~ but not stable Fr extraction efficiency ： < 0.3 % ~ quite small…What should be modified ：
① Oven material → sensitive to the work function ⇒ use material chemically stable② Temperature of the oven and target ~ low at present → ionization efficiency low ③ extraction electrode ~ optimize the shape and structure with simulation
Results ~ Fr production yield
0
500
1000
1500
2000
2500
3000
3500
4000
0 50 100 150
Run number
収量
(count/
sec)
~ beam intensity
World record at LNL/Italy
Extraction efficiency
Simulation with single track
Exp. data (target:1286K)
Exp. data (target:820K)
Targettemperature
Electrode Structure
Oven temperature
表面イオン化器加熱テスト
Oven 600℃; center 700℃
Partial melting of gold target
１８O beam
縦置き表面イオン化器
Swinger magnet
New version of Fr ion source
45°injection swinger magnet
Surface ionizer
Injection line for Rb（Oven etc）
Gold target
Fr Ions
Structure of
Surface Ionizer
18O beam Rbビbeam
Frイオン
oven
target
Einzel lenz
Extraction electrode
Target rod with cooling system
Beam transport system for Fr
DL2 DL4DL3Q2 Q4Q3
ThermalIonizer
850 850 850 100030004697
TMPTMP
Wall
Wall
1250
Neutralizer500D1
18O Q1
200
100
200
200et
430
300
・Layout of entire beam line
Ion optics
#5 target room
Swinger magnet
Room forTOF
ビーム輸送系の高真空度実現へ向けて
1. 境界条件：～表面イオン化器（10-6 torr）～MOT（10-9）
2. 電極等、構造をもつダクト内部のアウトガス軽減～石英ガラス管を電極内部に配置
3. コンダクタンスの悪い場所を複数配置し、段階的に真空度を上げる構造。～ダクトのサイズ等、検討中。
4. 設計～１２月までに完了5. 製作完了～３月6. 動作試験～３月末
収束電極～真空容器～２重構造 Differential Pumping
CYRIC1. seismic reinforcement—till Feb. 20102. Start construction of Fr beam transport line in Mar3. Re-start test of Fr production after Apr 20104. 10GHz ECR Ion Source ~ 18O beam ~ 1 uA5. High intensity laser cooled Fr factory
① Preparation of room for laser light source (Feb)② Lay optical fiber etc (Feb)③ Repair Swinger magnet system (Mar~Apr)④ Preparation of room for MOT/EDM (later)
①Laser Light Source Room
③Swinger Magnet
④MOT/EDM Detection Room
②Optical fiber ~ 150m
High intensity laser cooled Fr factory
1 4 7
10
13
16
19
22
25
28
31 n
1
10
100
1000
10000
event(arb. unit)
energy (MeV)
particle
emitted particles
n p alpha gamma
Neutron ~ a few MeV⇒ damage to detector (CCD etc..)⇒ MOT should be located
far from production target
Laser Cooling and Magneto Optical Trap (MOT))
ドップラー限界温度B
D kT
2Γ
=h
λ Γ/2π TD TR
87Rb 780 nm 5.9 MHz 145 μK 0.36 μK210Fr 718 nm 7.6 MHz 187 μK 0.18 μK
リコイル限界温度 2
222 1λM
hkMk
kTBB
R ==h
Trap: 718nm Repump: 817nm
F=11/2
F=13/2
F=9/2F=11/2F=13/2F=15/2
46.8 GHz
397 MHz500 MHz617 MHz
7s2S1/2
7p2P3/2
ECLD(External Cavity Laser Diodes )+Taper amp. for Rb trap
MOPA configuration : Master oscillator ~ ECLD ~ 10 mWPower amplifier ~ Taper amp. ~ 1 W
ECLD
Taper amp.
Collimation Lens
LD
GratingPiezoelectric element
LensLens TA
Peltierdevice
ECLD Taper amp.
LD
Grating
0
200
400
600
800
1000
1200
1400
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Taper Amp Current [mA]
Pow
er[
mW
] Achieve 1W
Produce light source for 795 nm, 817nm
3.8mmTrapped Rb atoms
Size ～3.8mmLifetime ～12 min. without lock circuit
Rb MOT
Presented by Dr.Giulio Stancari @ INFN Ferrara at ISOLDE workshop at CERN, Feb.2006
Fr from the decay of 225Ac
( shutdown )
→ to CYRIC
→ focus to Atomic Physics
Developments of experimental apparatus~ will be completed in 2011
Collaborators
Y. Sakemi, M.Itoh, K.Harada, H. Yoshida, H.Kawamura, T. Hayamizu, A.Oikawa, M.Sato, T.Saito (Tohoku U., CYRIC）
T. Aoki (U. Tokyo)
T.Murakami, K. Imai (Kyoto U.)
K. Hatanaka (Osaka U., RCNP）, T. Wakasa (Kyushu U.), M. Uchida (Tokyo Tech.)
Y. Shimizu （Tohoku U.）、H.Nataraj（Tohoku U., CYRIC from Sept. 2010）
Summary
Electron EDM Nuclei EDM
Search for e EDM using cooled radioactive atoms is under preparation.Fr has the largest enhancement factor for e EDM.Gong to use laser cooling and trap to improve coherence time.To achieve high detection sensitivity for EDM measurement---need high intensity Fr.Developing surface ionizer and beam transport system ---close to SUNY and LNL of production rate.Need more improvement on Fr ion source and primary beam, transport etc,
In 3 years aim to finish the preparation of all apparatus and start measurement.
Establish the next generation technics to search for EDM using cooled radioactive atoms.Promote search for EDM in lepton and hadron by using radioactive atoms with large enhancement factor.
