Transcript Present status of search for francium EDM

Present status of search for francium EDM
Detector Group, CYRIC, Tohoku University
Hirokazu Kawamura
contents
 Introduction
 CYRIC
 new ECRIS
 Swinger magnet
 Setup
 Surface Ionizer
 Beam Transport
 Neutralizer
 Laser trapping
 Research Plan
CYRIC Tohoku Univ., Univ. of Tokyo,
Tokyo Univ. Agri. Tech., RCNP Osaka Univ., Kyoto Univ.,
Tohoku Univ., Tokyo Inst. Tech., Kyusyu Univ.,
T. Aoki,
K. Harada,
M. Itoh,
A. Oikawa,
T. Sato,
T. Wakasa,
A. Hatakeyama,
T. Hayamizu,
H. Kawamura,
Y. Sakemi,
T. Shimizu,
H.P. Yoshida.
K. Hatanaka,
K. Imai,
T. Murakami,
M. Saito,
M. Uchida,
EDM search ~ Laser trap
High precision measurement in laser cooled/trapped 210Fr
1 nK
BEC
FD 1 mK
1 mK
Liq3He
Liq4He
1K
Room temp.
1000 K
temperature
Laser cooling
Evaporation cooling
Francium: Laser cooling to a few mK and trapping.
→ Very long interaction time!  Improve measurement precision!
E.D. Commins et al, 2002
Laser cooled/trapped atom
210Fr
Laser
1150
205Tl
K : Enhancement factor
585
~102 sec
t : Coherence time
3.2 min
T : Lifetime
Stable
~ 10-28
de : EDM (e cm)
~10-27
~10-3 sec
MOT
Heaviest Alkali Atom = 210Fr : Large Enhancement Factor
Cooling & Trapping  Long Coherence Time
Precision x 600 ~ Next Generation EDM Search
Atomic beam
High Intensity Laser Cooled Francium Factory at CYRIC
AVF Cyclotron
Primary beam: 100MeV 18O5+
Production: 18O+197Au→210Fr+5n
Beam Swinger
18O beam
Beam Transport/
Diagnosis System
Neutralizer
210Fr atom
209-210Fr
197Au
Zeeman Cooling
Magneto-Optical Trap
Cooled 210Fr
Surface Ionizer
210Fr+ ion
target
product. cross section
[mb]
100
10
1
70
80
90
100
Beam Energy [MeV]
New ECR Ion Source
10 GHz ECRIS
~ Request: Heavier Nuclide & Higher Energy
2008/July: Move from RIKEN
2009/May: Test start
2009/July: First acceleration
2009/July: Shutdown for Renovation
-- 2010/March
2010/June: First Run for Experiment
18O
beam New ECRIS: >2euA (next step), Old ECRIS: 100enA
Swinger magnet
2010/May: Swinger fixed @ 45 deg.
2010/May– Test Run, Performance Check
Surface Ionizer-I
Measured alpha-ray pectrum
210Fr
(6.543MeV)
target
beam
50-200um thick
gold electroplating
count
18O
197Au
206At
(5.703MeV)
Fr+ ion
on Ni-mount
CYRIC group
LNL (Italy)
Produced 210Fr
in Au target
1.4x107 atom/s
8x106 atom/s
Extracted 210Fr
4.1x104 atom/s
3x106 atom/s
Extraction efficiency
0.29%
40%
Stancari, NIMA594(2008)321
Surface Ionizer-II
Aim for: Fr+ yield > 106pps,
Extraction efficiency > 10%
(Ionizer-I: ~0.1%)
45 deg incident
Swinger magnet
18O beam
Fr ion
Rb beam
Surface ionizer
Production: 18O+197Au→210Fr+5n
 18O 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.
Fr ion
Einzel lens
Extraction electrode
Stable Rb beam
Oven (W)
197Au
target (1000 deg C)
1mm thick gold plate
Target rod (W)
Rb oven
(Rb atom beam source)
Offline Test
TOSCA Simulation
Electric field;
Finite Element Method
 Vacuum test
 Heating test
 Voltage apply test
collimate
18O
beam
extraction
Au target
Surface Ionizer-II
Rb ion beam first observed at viewer
on July 6
Fr Beam Transport
Beam line Overview
Ion Optics
(UeGios)
Requirement
1.
2.
3.
4.
High Transport Efficiency (~100%)
Focused Beam (φ5mm) @ Neutralizer
Extreme High Vacuum : Differential Pumping 10-6 to 10-9 Torr
Beam Diagnosis/Monitor System
Deflection electrode
Alignment Laser
& Radiation Thermometer
Electrode
Cable port
Alignment Laser
SSD
Under construction @ KT Science Ltd.
To be installed in August 2010.
Steering
Q-electrode
Electrostatic Quadrupole Triplets
TOSCA (FEM)
XZ
YZ
SiO2 duct
Reduce outgas from electrodes
After Baking (130V),
Simple Vacuum Test
We achieved 10-9 Torr ! ~ 1 week
Neutralizer
Which has a higher neutralization efficiency?
 Yttrium catcher
Y ~ EWF(3.1eV) < EIP(4.1eV) → Fr atom @ many laboratories!
 Charge exchange with Alkali vapor
Li+ + Na  Li + Na+ @ TRIUMF-ISAC
Fr+ + Rb  Fr + Rb+ @ SUNY
 Ion-Electron Recombination
Fr+ + e-  Fr + hν
1. Focused beam  high efficiency
2. Low energy  laser cooling
3. Ultrahigh vacuum  laser trapping
~ 700 mm
Fr+ ion ~ keV
Deceleration Focus
 ~ eV
Fr atom
Zeeman MOT
slower, chamber.
e-gun
Laser Focus
e-gun type Neutralizer
TOSCA (FEM)
Neutralizer
Very low recombination cross section?
Need to make energy very low?
Rb beam test is currently
in progress in Japan!
Offline setup
Laser lab.
COHERENT
Verdi + MBR110(Ti:S Laser)
to be installed in July/23
 718nm
F=3
F=15/2
617 MHz
500 MHz
397 MHz
F=13/2
72P3/2 F=11/2
F= 9/2
F=13/2
72P1/2 F=11/2
Cooling
718 nm
F=13/2
72S1/2
52P
267 MHz
157 MHz
72 MHz
F=2
3/2 F=1
F=0
6149 MHz
Cooling
Repumping
780 nm
817 nm
Repumping
795 nm
F=2
46.768 GHz
F=11/2
210Fr
52S1/2
6.834 GHz
F=1
87Rb
ECLD
+ Taper amp.
 780nm
Neutron Flight Path Cooled Francium Beamline
Laser lab.
Optical fiber (150m)
MOT
 Renovation  Clean room
 Design … Zeeman slower, MOT chamber
Research Plan
2010/July
Online test
-- Surface Ionizer + Beam Transport + Neutralizer
2010 High-intensity Fr-ion beam
2011 High-intensity neutral Fr atom + MOT
-- Complete Laser-Cooled Francium Facility
Fr+ extraction yield: 106 cps
Fr0 trap: 106 atoms  SUNY results
2012 Start EDM measurement
2013 Establish precision EDM measurement
-- Aim for World Record
de < 10-28 e cm
Experimental setup for surface ionizer-I
setup
18O5＋Beam
Triplet-Q
Extraction
241Am
electrode
(for SSD source test)
460mm
Fr＋
Fr＋
Fr＋
Fr＋
SSD
Fr＋
874mm
Fr＋
Primary beam line
Surface ionizer
197Au
Surface
ionizer
SSD:
detect alpha particle
from Fr on its surface.
SSD holder
@CYRIC
course-34
Beam transport system
Surface ionizer-II / Heating test
Shroud
Cathode
For Ultrahigh Vacuum of Beam Transport System
Surface Ionizer
Neutralizer
10-6
Calculation of Vacuum
TMP
10-7
TMP
10-8
400L/s *3
TMP
10-9
200
200
T　℃
Temperature [deg. C]
Pressure [Torr]
10-5
Q-electrode Heating Test
150
150
100
100
T　℃
T’
5050
00
900mm
0
200
400
x mm
600
800
Yttrium catcher neutralizer
to Trap
18O
n 1
 EWF  EIP 
 exp

0
n
2
kT


beam
Fr atom
Fr ion
Au target
Y target
Surface Ionizer
Target : Gold (Au) ~ EWF(5.1eV)>EIP(4.1eV) → Fr+ ion
Target : Yttrium (Y) ~ EWF(3.1eV)<EIP(4.1eV) → Fr atom
Neutralizer
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
Velocity distribution
Heating
(~1000K)
0.0035
vFr~281 m/s, vrms~345 m/s
0.003
0.0025
Fr ion
Fr atom
fraction
0.002
vRb~333 m/s , vrms~408 m/s
0.0015
0.001
Y target
20
0.0005
Neutralized Fr atom is diffused.
0
0
100
200
300
400
500
Atom velocity (m/s)
210Fr@T=1000K
85Rb@T=568K
600
700
800
Ionization/Recombination constant
Oxygen
Ionization
Ar
Recombination
Omegatron (user) has
succeeded in the
neutralization of Ar (O).
1eV
Ne
1eV
(rare gas)
1keV
1keV
1eV
(Alkali metal)
Na
1eV
1keV
1keV
http://www.omegatron.co.jp
Application of deceleration-type slow-neutral beam generator
to thin-film (Nitride or Oxidize film) production
Ion accel. 1000eV
VDS ~80eV
anode
target
Neutralizer
2nd focus lens
Decel. lens
1st focus lens
Extract. electrode
O2
Electron bombard type
Discharge chamber
1012 atoms/sec
Equivalent energy ~ 20-30eV
target
Atoms soft-landing on target  thin-film produced
Heating holder
Valid gas … O, N, Ar and rare gas
Neutralization using Alkali vapor
0eV 1keV 5keV10keV Rb+ energy
|
|
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TRIUMF-ISAC
Cs+-Cs
Na vapor density ~ 1014 atom/cm2
Rb+-Rb
Neutralization efficiency ~ 95%
Vacuum pressure ~ 2x10-7 Torr (= 3x10-5 Pa)
Fr+-Rb
8Li energy ~ 30keV
SUNY (Sprouse)
Rb+-Cs
Rb vapor density ~
5x1013
atom/cm3
Cs+-Rb
Neutralization efficiency >80%
210Fr energy ~ 5keV
Perel,Phys.Rev.138(1965)A937
Laser transport
Laser room : non-radiation controlled area
Laser for Rb
Trap Laser
EDLD
Grating
Laser for Fr
Laser for Sr
TA
Fr cooling/MOT/
Laser Trap
Sr cooling/MOT
LD
Optical fiber (~150m)
TOF tunnel
Neutral Fr atom
MOT
Laser cooling
Next generation EDM search: … Fr-Sr
Ultraslow polar molecule at Feshbach resonance
Laser
Trap
“Science trap”
Sr cooling/trap system