Searching for a n EDM at PSI

Searching for a n. EDM at PSI

The collaboration

UCN source at PSI Proton Accelerator 590 Me. V Cyclotron 2. 2 m. A beam current n. EDM UCN Source

Outline

Apparatus overview

The apparatus

Outline

Empty UCN operation Filling Monitor A. Serebrov et al. , NIMA 545(2005)490

UCN detector 6 Li 3 H depleted 6 Li Signal (m. V) 110 µm 60 µm UCN enriched Time (ns) G. Ban et al. , NIMA 611 (2009) 280

UCN Detector G. Ban et al. , NIMA 611 (2009) 280

UCN emptying curve τflip = 236 s τloss =16. 5 s τ↓ = 163 s τ↑ = 16. 9 s N = 29185 α 0 = 0. 999

UCN storage time

UCN Spin performance

UCN Ramsey cycles Ramsey curve taken with 250 s precession time

Outline

The measurement technique Measure the difference of precession frequencies in parallel/anti-parallel fields:

Magnetic shield

Surrounding field compensation

Sensor positions Z Monitoring positions close to shield (~ 0. 3… 0. 8 m) n. EDM Coordinate system Al frame FG 9 d or o er Th Magnetic shield (fi m rs o h tf o lo us or e ) Y X

Results Feedback with inverted & regularized Matrix • Twelve sensors close to shield taken into account (for x-direction shown below: sensors 0 x, 3 x, 6 x, and 8 x are used)

Systematic effects

Hg co-magnetometer

Principle of Cs magnetometer

Cesium magnetometers ± 140 k. V

Adjusting field gradients

Gradients

Outline

High voltage

Testing high voltage

Leakage currents are caused by the high voltage and appear along the surface of the insulator ring. jr jφ jφ jz jr jφ A leakage current of 1 n. A produces a false edm of 2 × 10 -28 e cm

Leakage current measurement 3. 5600 3. 5595 3. 5590 3. 5585 3. 5580 3. 5575 3. 5570 3. 5565 0. 9 3. 5560 0. 6 3. 5555 0. 3 0 2 4 6 8 10 0. 0 -0. 3 -0. 6 -0. 9 -80 -60 -40 -20 0 20 40 60 80

Outline

n 2 EDM: General concept

Thermohouse 2

Conclusion & Outlook

The Neutron EDM Collaboration