Magnetic/Electric Fields for KEK-RCNP EDM Experiment K. Matsuta(Osaka), Y. Masuda(KEK), Y. Watanabe(KEK), S.C. Jeong(KEK), K. Hatanaka(RCNP), R. Matsumiya (RCNP), S. Kawasaki(KEK), M. Mihara(Osaka), A. Miller(TRIUMF), C. Bidinosti(Winnipeg), Y. Shin(TRIUMF ） and other KEK-RCNP members UCN ρ = 26 E C = 90 neV

E 10 kV/cm H o 1 μT n spin s 1st RF pulse γH 1 t = π/2 Principle of EDM measurement (ω-ω o )t c E reversal for extraction of d n RF frequency ω P n cos(ω-ω o )t c UCN bottle ω o : 2μ n H o ± 2d n E t c : precession time δd sta = h/{2P n Et c √N} P n : UCN polarization N : number of UCN nEDM

E 10 kV/cm H o 1 μT n spin s 1st RF pulse γH 1 t = π/2 Principle of EDM measurement (ω-ω o )t c E reversal for extraction of d n RF frequency ω P n cos(ω-ω o )t c UCN bottle ω o : 2μ n H o ± 2d n E t c : precession time δd sta = h/{2P n Et c √N} P n : UCN polarization N : number of UCN nEDM

Systematic errors at ILL × e.cm 1 Door cavity dipole -5.6 ±2.0 2 Other dipole fields 0.0 ±6.0 3 Quadrupole difference -1.3 ±2.0 4 v×E translational 0.0 ± v×E rotational 0.0 ±1.0 6 Second-order v×E 0.0 ± Hg light shift (geo phase) 3.5 ±0.8 8 Hg light shift (direct) 0.0 ±0.2 9 Uncompensated B drift 0.0 ± Hg atom EDM -0.4 ± Electric forces 0.0 ± Leakage currents 0.0 ± AC fields 0.0 ±0.01 Total -3.8 ±7.2 Sensitive magnetometer removes magnetized material. superparamagnetic material/ superconductor Spherical coil removes quadrupole component. reduced ∂B/∂z = 0.1 nT/m with small cell Magnetic shielding Non-cylindrically symmetric field magnetic material ∂B/∂z = 1 nT/m

Ramsey resonance for EDM UCN filling UCN detection Ramsey resonance V F + μH 210 neV ± 120 neV 90 neV 330 neV 170 neV max

Ramsey resonance with present UCN source π/2 RF coil Spherical coil Rotary valve Polarizer/analyzer Spin flipper UCN detector UCN valve Door valve EDM cell

DLC coating DegreasingUntreated  = ± 1.4 s  = 75.8 ± 2.3 s  = 24.7 ± 0.9 s Silica + Silica + CuBe π/2 RF coil EDM cell UCN storage time in the EDM Cell

Ramsey resonance 2009 (ω-ω o )t c = -4π -2π 0 2π 4π -5π -3π -π π 3π 5π two coherent RF pulses t t t c = 100ms 200 mG Effect of P n cos(ω-ω o )t c visibility α = (N max – N min )/(N max + N min ) = 0.9 π/2

Ramsey resonance s Ramsey fringe two coherent RF pulses t t t c = 30 s tc = 30 s, α= 0.33 H 0 = 20 mG 1/30 Hz resonance freq.

Visibility as a function of tc T 2 〜 50 s 1/T 2 = ( ω 0 δB/B 0 ) 2 τ S.Flipp et al. / NIM A 598 (2009) 571 Where τ=λ/v ucn

Bz field distribution EDM cell δBz=4nT δBz/B 0 〜 0.2% 1/T 2 = ( ω 0 δB/B 0 ) 2 τ = 1/44 1/s ω 0 (δB/B 0 ) = ２ π (60Hz)×(0.2%) = /s τ = λ/v ucn = (4V/S)/ v ucn = 0.04 sec dB z /dz = 25 [nT/m] Consistent with The experimental T 2

Trim coil adjusted

Z X Y Geomagnetic field 3D field simulation (OPERA-3d) Observatio n(mG) Simulation( mG) Vertical Horizontal 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)

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 Only holes Chimney Z(cm) Geomagnetic field

Field simulation(OPERA-3d) No of LayersBz(nT)dBz/dz (nT/m) 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 m size m size nT

2m size coil 4m size coil Y=0 Z=0 1nT

1/5 scale model of Compensation coil 3axes – flux gate sensor X Z Y

Experimental setup for EDM at New UCN source Increase UCN transport efficiency 25

UC N

IEEE TRANSACTIONSON POWER APPARATUS AND SYSTEMS, VOL. PAS-88, kV/cm 10 5 Extrapolation ? Our data Phys. Lett. A 376 (2012) 1347

Electric field simulation for HV cell homogeneity ~ should be homogeneous to avoid vxE effect for rotational flow strong field have to avoid discharge Silica HV Cell

vxE r v ErEr EDM Cell E d f = μ c2c2 1 V ErEr E = (6 x ecm) ErEr E x(Degree of rotational flow)x

Summary Present dB/dz 〜 25 nT/m or δBz = 4nT tc = 30 s Ramsey ts = 120 s T1 〜 1000 s T2 =50 s B field Improvement 4 layer shield Demagnetization Compensation coil E filed  1 nT/m  0.1nT/m Structure Designing for small leakage and good homogeneity And good breakdown character with Xe gas Xe co-magnetometer With Fluxgate and K magnetometer 2013 Test of the New UCN source High voltage application test EDM SC polarizer 2013 〜 ? TRIUMF