Magnetic/Electric Fields for KEK-Magnetic/Electric Fields for KEK-RCNP EDM ExperimentRCNP EDM Experiment

K. MatsutaK. Matsuta(Osaka)(Osaka) , Y. Masuda , Y. Masuda(KEK)(KEK), Y. Watanabe, Y. Watanabe(KEK)(KEK), , S.C. JeongS.C. Jeong(KEK)(KEK), K. Hatanaka, K. Hatanaka(RCNP)(RCNP), R. Matsumiya , R. Matsumiya (RCNP)(RCNP), , S. KawasakiS. Kawasaki(KEK)(KEK), M. Mihara, M. Mihara(Osaka)(Osaka), A. Miller, A. Miller(TRIUMF)(TRIUMF), , C. BidinostiC. Bidinosti(Winnipeg)(Winnipeg), Y. Shin, Y. Shin(TRIUMF(TRIUMF ）） and other KEK-RCNP and other KEK-RCNP membersmembers

UCN source @RCNP

ρ = 26 UCN/cm3@ EC = 90 neV

E10 kV/cm

Ho

1 μT

n spin s1st RF pulseγH1t = π/2

Principle of EDM measurementPrinciple of EDM measurement

(ω-ωo)tc

E reversal for extraction of dn

RF frequency ω

Pnco

s(ω

-ωo)t

c

UCN bottle

ωo: 2μnHo ± 2dnE tc: precession time

δdsta = h/{2PnEtc√N}Pn : UCN polarizationN : number of UCN

nEDM

E10 kV/cm

Ho

1 μT

n spin s1st RF pulseγH1t = π/2

Principle of EDM measurementPrinciple of EDM measurement

(ω-ωo)tc

E reversal for extraction of dn

RF frequency ω

Pnco

s(ω

-ωo)t

c

UCN bottle

ωo: 2μnHo ± 2dnE tc: precession time

δdsta = h/{2PnEtc√N}Pn : UCN polarizationN : number of UCN

nEDM

Systematic errors at ILL

×10-27 e.cm1 Door cavity dipole -5.6 ±2.02 Other dipole fields 0.0 ±6.03 Quadrupole difference -1.3 ±2.0

4 v×E translational 0.0 ±0.035 v×E rotational 0.0 ±1.06 Second-order v×E 0.0 ±0.027 Hg light shift (geo phase) 3.5 ±0.88 Hg light shift (direct) 0.0 ±0.29 Uncompensated B drift 0.0 ±2.410 Hg atom EDM -0.4 ±0.311 Electric forces 0.0 ±0.412 Leakage currents 0.0 ±0.113 AC fields 0.0 ±0.01Total -3.8 ±7.2

Sensitive magnetometer removes magnetized

material.

superparamagnetic material/

superconductor

Spherical coil removesquadrupole component.

reduced ∂B/∂z = 0.1 nT/mwith small cell

Magnetic shielding

Non-cylindricallysymmetric field

magnetic material

∂B/∂z = 1 nT/m

Ramsey resonance for EDM

UCN fillingUCN detectionRamsey

resonance

VF + μH210 neV ± 120 neV

90 neV 330 neV

170 neV max

Ramsey resonance with present UCN Ramsey resonance with present UCN source source

π/2 RF coilπ/2 RF coil

Spherical coilSpherical coil

Rotary valveRotary valve

Polarizer/analyzerPolarizer/analyzer

Spin flipperSpin flipper

UCN detectorUCN detector

UCN valveUCN valveDoor valveDoor valve

EDM cellEDM cell

DLC coating

DegreasingUntreated

τ = 119.5 ± 1.4 s

τ = 75.8 ± 2.3 sτ = 24.7 ± 0.9 s

Silica +

Silica + CuBe Silica + CuBe

π/2 RF coil

EDM cell

UCN storage timein the EDM Cell

Ramsey resonance Ramsey resonance 20092009

(ω-ωo)tc =

-4π-2π 0 2π 4π

-5π-3π

-π π3π

5π

two coherent RF pulses

t t

tc=100ms

200 mG

Effect of Pncos(ω-ωo)tc

visibility α = (Nmax – Nmin)/(Nmax + Nmin) = 0.9

π/2 π/2

Ramsey resonance Ramsey resonance 20102010

30 s Ramsey fringe two coherent RF pulses

t ttc=30 s

tc = 30 s , α= 0.33

H0 = 20 mG

1/30 Hz

resonance freq.

Visibility as a function of tc

T2 〜 50 s

1/T2 = (ω0 δB/B0)2

τ

S.Flipp et al. / NIM A 598 (2009) 571Where τ=λ/vucn

Bz field distribution

EDM cell

δBz=4nTδBz/B0 〜 0.2%

1/T2 = (ω0 δB/B0)2 τ = 1/44 1/s

ω0(δB/B0) = ２ π (60Hz)×(0.2%) = 0.75 1/sτ = λ/vucn = (4V/S)/ vucn = 0.04 sec

dBz/dz= 25 [nT/m]

Consistent withThe experimental T2

Trim coiladjusted

Z

X

Y

Geomagnetic field

3D field simulation (OPERA-3d)

　 Observation(mG)

Simulation(mG)

Vertical 3.7 -0.22

Horizontal

-2.8 0.07

Observation

Simulation

1μF

100Ω

0.1Ω

6 回巻き 1 回巻き

B(T)

H(A/m)

消磁のヒステリシスループの軌跡

消磁回路図

消磁前後で比較 (Br)

消磁前後で比較 (Br)

磁気シールドの下の穴の部分に煙突があるとき、ないときの比較

X

X

Z

Z

0

8060

4020

-20

-40

-60

-80

Only holes

Chimney

Z(c

m)

Z(c

m)

Geomagnetic field

Field simulation(OPERA-3d)

No of Layers Bz(nT) dBz/dz (nT/m)

1 -355.8 480.6

2 -27.2 55.4

3 -3.2 8.6

4 -0.7 2.9

Multi-layer suppression

X

Y

Geomagnetic field

Z

Y

Z

X

Compensation コイル

2D Magnetic field distribution for 2msize model

　 Bz(nT) dB/dz(nT/m)

No coil -0.73 2.89

2m size 0.03 1.68

4m size 0.0004 0.07

1nT

2m size coil

4m size coil　 　

Y=0

Z=0

1nT

1/5 scale model of Compensation coil

3axes – flux gate sensor

X

ZY

Experimental setup for EDMat New UCN source

Increase UCN transport efficiency

25

UCN

IEEE TRANSACTIONSON POWER APPARATUS AND SYSTEMS, VOL. PAS-88, 1969

10kV/cm

105

Extrapolation ?

Our data

Phys. Lett. A 376 (2012) 1347

Electric field simulationfor HV cell

homogeneity~ 10-2

should be homogeneousto avoid vxE effect for rotational flow

strong field

have to avoiddischarge

vxEr

v

ErEDM Cell

E

df = μc2

1V Er

E= (6 x 10-22 ecm) Er

Ex (Degree of rotational flow)x

SummaryPresent dB/dz 〜 25 nT/m or δBz = 4nTtc = 30 s Ramsey ts = 120 sT1 〜 1000 s T2 =50 s

B field

Improvement 4 layer shield Demagnetization Compensation coil

E filed

1 nT/m 0.1nT/m

Structure Designingfor small leakage and good homogeneityAnd good breakdown character with Xe gas

Xe co-magnetometer

With Fluxgate and K magnetometer

2013 Test of the New UCN sourceHigh voltage application test

EDMSC polarizer

2013 〜 2014

2015? TRIUMF