1. 03.07.2016nEDM-2014, 2-6 November 20141 Crystal diffraction nEDM experiment. Present status Voronin Vladimir PNPI, Gatchina, Russia

2. Outline The method idea Test experiments Full scale setup with quart crystal Possibility to improve Summary 03.07.2016 nEDM-2014, 2-6 November 2014 2

3. 03.07.2016 nEDM-2014, 2-6 November 2014 3 Neutron EDM Non zero EDM means the P and T violation P P – spatial inversion С С – particle – antiparticle inversion Т Т – time inversion CPT theorem (Lüders (1954); Pauli(1955)) (Our world is СРТ invariant) Non zero nEDM means СР violation

4. 03.07.2016 nEDM-2014, 2-6 November 2014 4 History of nEDM experiment Standard model d n ~(10 -31 -10 -33 ) e cm New physics to explain the baryon asymmetry (experiment - n b /n  ~10 -11 SM - n b /n  ~10 -21 ) d n ~(10 -25 -10 -30 ) e cm Neutron scattering in-flight magnetic resonance UCN magnetic resonance

5. 03.07.2016 nEDM-2014, 2-6 November 2014 5 Idea nEDM experiment 2(E·D) -E +EDD Interaction time with Е Sensitivity to nEDM Neutron size R n ~ 10 -13 cm, d n /R n ~ 3  10 -13. Corresponding size from Earth is ~ 2 μm Current accuracy to d n

6. 03.07.2016 nEDM-2014, 2-6 November 2014 6 Sensitivity to neutron EDM E~ grad V e ~(0.1-1)GV/cm UCN method Crystal-diffraction method E ~ a few 10 kV/cm τ ~ 1000s (time of life) Е τ ~ 10 7 (V·s)/cm Е τ Now Е τ ≈ 10 6 (V·s)/cm τ a ~ 0.01 c (absorption) 10 7 (V·s)/cm ЕτЕτЕτЕτ Electron bonding energy ~ a few eV Å

7. Potential of neutron interaction with crystal For nonabsorbing potential V(r), i.e. Amplitude and phase of g-harmonics g=2 π/d 03.07.2016 nEDM-2014, 2-6 November 2014 7

8. Neutron wave function in crystal - neutron wave vector in crystal 03.07.2016 nEDM-2014, 2-6 November 2014 8

9. Neutron energy in crystal For the case of non- centrosymmetric crystal Neutron energy in crystal depends on the spin direction near the Bragg reflex 03.07.2016 nEDM-2014, 2-6 November 2014 9

10. 03.07.2016 nEDM-2014, 2-6 November 2014 10  /2 Idea of the experiment For  /2 reflection E || v n and H s ~[E x v n ]≈0+E-E

11. 03.07.2016 nEDM-2014, 2-6 November 2014 11 Electric field quartz (110) plane L c =14 cm Bragg angle ≈ 86 0 -0.8 · 10 8 V/cm Theory + 0.8·10 8 V/cm Variation of the  T on  1K E ≈  10 8 V/cm

12. nEDM-2014, 2-6 November 2014 12 π/2 reflection “zero” [v x E] For  /2 reflection E || v n and H s ~[E x v n ]≈0 g vv V || +E -E 03.07.2016

13. Scheme of the experiment 13 03.07.2016 nEDM-2014, 2-6 November 2014 H≈0 T=T 0 T=T 0 +ΔT

14. 3-D polarization analyzes Magnetic field || surface of the superconductor. H L ≈0H L ≠0 P Current accuracy of spin orientation is ~10 -2 rad ~10 -2 rad for routine experiment ~10 -3 rad ~10 -3 rad can be reached for special cases F. Tasset, P.J. Brown, E. Lelie`vre-Berna, T. Roberts, S. Pujol, J. Allibon, E. Bourgeat-Lami, Physica B, 267-268 (1999) 69-74 03.07.201614 nEDM-2014, 2-6 November 2014

15. 15 Matrix of spin rotation H s ~[E x v n ]  E||Z EDM and [v x E] effects give an orthogonal matrix elements EDM[v x E]Residual magnetic field H e =(E d n )/  n 3D spin analysis allows to separate the EDM and [v x E] effect. PiPi PfPf M+M+ M-M- X Y Z 03.07.2016

16. nEDM-2014, 2-6 November 2014 16 Spatial distribution of [v x E] PiPi PfPf M+M+ M-M- X Y Z  P=P(  T + )-P(  T - ) We should observe the same dependence for Pxy and Pyx components responsible for nEDM

17. 03.07.2016 nEDM-2014, 2-6 November 2014 17 nEDM spatial distribution We don’t see the spatial dependence of Pxy and Pyx components responsible for nEDM. [v x E]  P s < 1.1 10 -4 stat. accuracy is  P~1.5 10 -4

18. 03.07.2016 nEDM-2014, 2-6 November 2014 18 nEDM test experiment (PNPI-ILL) 1.Field value coincide with the theory E= (0.7±0.1) 10 8 V/cm for (110) quartz plane 2.The statistical sensitivity was ~1.6 10 -23 e cm/day. 3.The sensitivity can be improved by a factor of 65 and reach about 2.5 10 -25 e cm/day for the full scale experiment, mainly by increasing the divergence acceptance of the installation, the beam size, and the crystal length.

19. 03.07.2016 nEDM-2014, 2-6 November 2014 19 Residual magnetic field Value Time stability Accuracy of polarization 3D analysis Angular crystals alignment Precision of temperature control Δd/d < 10 -5 ~0.01 arc degree Flatness windows of CRYOPAD Interplanar space variation ~0.01 K Summary of systematics to reach the 10 -26 e cm Summary of systematics to reach the σ d ~10 -26 e cm

20. Full scale setup is now under construction 20 03.07.2016 nEDM-2014, 2-6 November 2014

21. 03.07.2016 nEDM-2014, 2-6 November 2014 Quartz crystal test. Main idea Backscattering geometry Sample Reference crystal Bragg width of neutron reflex in  d/d is ~10 -5 21

22. 03.07.2016 nEDM-2014, 2-6 November 2014 22 Quartz crystal test

23. 35 100 Y Z X 105х100х500 mm 3 Summary crystal size is 105х100х500 mm 3 (15 item with 35х100х100 mm 3 ) Interplanar space dispersion is  d/d=  2  10 -6  d/d=  2  10 -6 over the all crystal Quartz crystal 03.07.2016 nEDM-2014, 2-6 November 2014 23

24. The CRYOPAD-EDM parameters: 600 mm Inner size for crystal is 600 mm. 100х100 mm 2 Size of the windows for neutron beam 100х100 mm 2. 10 -3 rad The entrance and outgoing windows should be parallel with accuracy 10 -3 rad. 10 -3 рад Homogeneity of magnetic field over the windows should be about 10 -3 рад. CRYOPAD-EDM 03.07.201624 nEDM-2014, 2-6 November 2014

25. CRYOPAD-EDM (ILL design) General view Inner coil for longitudinal polarization analysis ~ 10 -4 Homogeneity of the field is ~ 10 -4 03.07.201625 nEDM-2014, 2-6 November 2014

26. Input and output nutators It was found a geometry of the nutators allowing to get a misalignment of the field on the Meissner screens which will be of the order of ± 3 10 -4 on the whole section of the beam (100 x 100 mm 2 ). 03.07.201626 nEDM-2014, 2-6 November 2014

27. 03.07.2016 nEDM-2014, 2-6 November 2014 27 Sensitivity for the quartz crystal For the 100x100x500 mm 3 (110) plane it can be 2 10 -26 е см per 100 day How to improve this sensitivity?

28. 03.07.2016 nEDM-2014, 2-6 November 2014 28 New non-centrosymmetric crystal request Low neutron absorption No center of symmetry Elements with large Z  d/d < Bragg width (~10 -5 Perfect crystal (  d/d < Bragg width (~10 -5 ))

29. 03.07.2016 nEDM-2014, 2-6 November 2014 29 CrystalSymmetry group hkld, (Å)E g, 10 8 V/cm  a, ms E g  a, (kV  s/cm)  -quartz (SiO 2 ) 32(D 6 3 )1112.236 2.31230 1102.4572.0 200 Bi 12 SiO 20 I234331.75 4.341720 4441.464.65 1860 Bi 12 GeO 20 I234331.744.651465 4441.464.8 480 PbOP c a 210022.9410.411040 0041.47101000 BeO6mm0112.065.473700 2011.136.5 4500 Parameters of some NCS crystals

30. 03.07.2016 nEDM-2014, 2-6 November 2014 30 Storage variant t=0 0<t<2t a t=2t a 3 He cell Detector HfHf HiHi Perfect crystal reflection T=T 0 T=T 0  T Up to 1000 reflections (  s ~1 s) M.R. Jaekel, C.J. Carlile, E.Jericha, D.E. Schwab and H. Rauch, SPIE Vol. 3767 EUV, X-Ray, and Neutron Opticas and Sources, 353 (2000)

31. 03.07.2016 nEDM-2014, 2-6 November 2014 31 Some numerical estimation Bragg width – Responsible time – Crystal acceleration – (fast piezoelectric element?)

32. 03.07.2016 nEDM-2014, 2-6 November 2014 32 Sensitivity estimation for Sensitivity estimation for Bi 12 SiO 20 (444) E g, 10 8 V/cm , ms Count rate K inp  d, e  cm per day  -quartz (110) in-flight 2.00.6 (L=50cm) 10 4 n/s (ILL PF1) (2-3)10 -25 Bi 12 SiO 20 (444) storage 4.658 (L=15 cm) 10 3 n/s (ESS) 10 (2-3)10 -26

33. 03.07.2016 nEDM-2014, 2-6 November 2014 33 Conclusion  d ~(2-3)·10 -26 e·cm per 100 day Full scale setup with quartz crystal are now under construction. Expected sensitivity is  d ~(2-3)·10 -26 e·cm per 100 day Storage modification of crystal-diffraction nEDM experiment can reach a sensitivity  d ~(2-3)·10 -27 e·cm  d ~(2-3)·10 -27 e·cm for the European Spallation Source and BSO crystal