1. Axion dark matter search:
23 July 2014
Lepton Moments, Cape Cod
The Storage Ring Proton EDM experiment Yannis Semertzidis, CAPP/IBS at KAIST
Strong CP-Problem
Axion dark matter search:
State of the art axion dark matter experiment in Korea
Collaborate with ADMX, CAST…
Proton Electric Dipole Moment Experiment
Storage ring proton EDM
Muon g-2, mu2e, etc.

2. Korean Alphabet (Hangul, 1443AD)
24 characters, consonants and vowels
Easy to read, understand short sentences, orient yourself at public places
Hard to understand complicated sentences
Many people understand English

3. Center for Axion and Precision Physics Research: CAPP/IBS at KAIST, Korea
Four groups
15 research fellows, ~20 graduate students
10 junior/senior staff members, Visitors
Engineers, Technicians
Future: IBS building at KAIST

4. CAPP Group http://capp.ibs.re.kr/html/capp_en/
Three more Research Fellows signed up already…

5. Storage Ring Proton EDM

6. Proton storage ring EDM experiment is combination of beam + a trap

7. Yannis Semertzidis, CAPP/IBS, KAIST
Stored beam: The radial E-field force is balanced by the centrifugal force. E
Yannis Semertzidis, CAPP/IBS, KAIST
Yannis Semertzidis, BNL 7

8. Yannis Semertzidis, CAPP/IBS, KAIST
The proton EDM uses an ALL-ELECTRIC ring: spin is aligned with the momentum vector
at the magic momentum E
Momentum
vector
Spin vector
Yannis Semertzidis, CAPP/IBS, KAIST
Yannis Semertzidis, BNL 8

9. The proton EDM ring Total circumference: 300 m Bending radius: 40 m
Straight sections are instrumented
with quads, BPMs, polarimeters,
injection points, etc, as needed.

10. Feasibility of an all-electric ring
Two technical reviews have been performed at BNL: Dec 2009, March 2011
Fermilab thorough review. Val Lebedev considers the concept to be sound.
First all-electric ring:
AGS-analog
Ring radius 4.7m
Proposed-built
It worked!

11. srEDM International Collaboration
COSY:
Strong collaboration with Jülich/Germany continues
We’ve been doing Polarimeter Development, Spin Coherence Time benchmarking, Syst. Errors, Beam/Spin dynamics simulation, etc. for >5 years w/ stored pol. beams.
JLAB: breakthrough work on large E-Fields
KOREA:
We are forming the EDM group and getting started with system developments.
ITALY (Ferrara, Frascati,…)
TURKEY (ITU,…)
GREECE (Demokritos, …)
Three PhDs already: KVI, Ferrara, ITU

12. The proton EDM ring evaluation Val Lebedev (Fermilab)
Beam intensity 1011 protons limited by IBS
, kV

13. pEDM polarimeter principle (placed in a straight section in the ring): probing the proton spin components as a function of storage time
Micro-Megas detector, MRPC or Si.
“defining aperture”
polarimeter target
Extraction: lowering the vertical focusing
carries EDM signal
increases slowly with time
carries in-plane (g-2) precession signal

14. Polarimeter design, rates:
Beam rates ~102 Hz/cm2 on average, higher at small radius. Design: ~1KHz/pad.
Store bunches with positive/negative helicity for pol. syst. errors.
70 cm

15. The EDM signal: early to late change
Comparing the (left-right)/(left+right) counts vs. time we monitor the vertical component of spin
M.C. data
(L-R)/(L+R) vs. Time [s]
Opposite helicity bunches
result to opposite sign slopes

16. Large polarimeter analyzing power at Pmagic!
Yannis Semertzidis, BNL

17. Our proton EDM plan
Develop the following systems (funded by IBS/Korea, COSY/Germany, applying for NSF support, and DOE-HEP/NP):
SQUID-based BPM prototype, includes B-field shielding (UMass, CAPP/Korea, BNL,…)
Polarimeter development (Ind. Univ., CAPP, COSY,…)
Electric field prototype (Old Dom. Un. (NSF), JLab,…)
Study of systematic errors (BNL, FNAL, Cornell,…)
Precision beam and spin dynamics simulation (BNL, CAPP, Cornell, COSY,…)
Lattice optimization, beam diagnostics (MSU (NSF),…)

18. Clock-wise (CW) & Counter-Clock-wise Storage
Any radial magnetic field sensed by the
stored particles will also cause their
vertical splitting. Unique feature among EDM experiments…
Equivalent to p-bar p colliders in
Magnetic rings 18

19. Distortion of the closed orbit due to Nth-harmonic of radial B-field
Clockwise beam
Y(ϑ)
The N=0 component
is a first order effect!
Counter-clockwise
beam
Time [s]

20. Vertical tune modulation frequency: 10 kHz
Noise level: 0.9 fT/√Hz
Vertical tune modulation frequency: 10 kHz

21. SQUID gradiometers at KRISS

22. SQUID gradiometers at KRISS

24. B-field Shielding Requirements
No need for shielding: In principle, with counter-rotating beams.
However: BPMs are located only in straight sections  sampling finite. Nyquist theorem limits sensitivity to low harmonics of Br. Hence the B-field needs to be less than (1-10nT) everywhere to reduce its effect. We are building a prototype!

25. Peter Fierlinger, Garching/Munich
Issues: demagnetization,
effect of holes, etc.

26. Peter Fierlinger, Garching/Munich

27. International srEDM Network Common R&D
srEDM Coll. pEDM
Proposal to DOE HEP, NP
SQUID-based BPMs
B-field shielding/compensation
Precision simulation
Systematic error studies
E-field tests …
JEDI (COSY/Jülich)
Pre-cursor EDM exp.
Polarimeter tests
Spin Coherence Time tests
Precision simulation
Cooling
E-field tests …

28. What has been accomplished?
Polarimeter systematic errors (with beams at KVI, and stored beams at COSY).
Precision beam/spin dynamics tracking.
Stable lattice, IBS lifetime: 7500s.
Spin coherence time >300s, role of sextupoles (with stored beams at COSY).
Feasibility of required electric field strength ~40kV/cm – 100kV/cm, 3cm plate separation
Analytic estimation of electric fringe fields and precision beam/spin dynamics tracking. Stable!
Already published or in progress.

29. Tracking results using realistic (analytic estimations of) fringe fields
E. Metodiev et al.,
to appear in PRSTAB
The radial position away from the ideal orbit as a function of ring X and Y coordinates.

30. Jlab E-field breakthrough
Large grain Nb, no detectable dark current up to (max avail.) 18 MV/m and 3cm plate gap
TiN coated Al plates reach high E-field strength
Jlab to develop large surface plates

31. Field Emission from Niobium
Work of M. BastaniNejad
Phys. Rev. ST Accel. Beams, 15, (2012)
Buffer chemical polish: less time consuming than diamond paste polishing
DPP stainless steel
Fine grain niobium
Large grain niobium
Single crystal niobium
Field strength > 18 MV/m
Conventional High Voltage processing: solid data points
After Krypton Processing: open data points

32. Work of Md. A. Mamun and E. Forman
What about TiN-coated Aluminum?
No measureable field emission at 225 kV for gaps > 40 mm, happy at high gradient
Bare Al
TiN-coated Al
the hard coating covers defects
Work of Md. A. Mamun and E. Forman

33. Technically driven pEDM timeline13 14 15 16 17 18 19 20 21 22
Two years system development
One year final ring design
Three years beam-line construction and installation

34. Jülich, focus on deuterons, or a combined machine
EDMs: Storage ring projects
pEDM in all electric ring in the USA
Jülich, focus on deuterons, or a combined machine
(from A. Lehrach)
CW and CCW propagating beams

35. The Proton EDM experiment status
Support for the proton EDM:
CAPP/IBS, KAIST in Korea, R&D support for SQUID-based BPMs, Prototype polarimeter, Spin Coherence Time (SCT) simulations.
COSY/Germany, studies with stored, polarized beams, pre-cursor experiment.
After the P5 endorsement DOE-HEP requested a white paper to establish the proton EDM experimental plan.
Large ring radius is favored: Lower E-field strength required, Long SCT, 1-10nT B-field tolerance in ring. Use of existing ring preferred.

36. The JEDI experiment status
Helmholtz Foundation evaluation, early 2014.
The pre-cursor experimental program is approved: Use of the existing COSY ring, slightly modified to become sensitive to deuteron EDM (RF-Wien filter).
EDM sensitivity moderate, but significant as first direct measurement.
Asked to prepare a CDR for a sensitive storage ring EDM experiment.

37. Summary
The storage ring proton EDM has been developed. The breakthrough? Statistics!
Best sensitivity hadronic EDM method.
Both efforts (USA and COSY) received encouragement to produce an experiment plan.
pEDM first goal ecm with a final goal ecm. Complementary to LHC; probes New Physics ~ TeV.

38. Extra slides

39. Peter Fierlinger, Garching/Munich

41. Why now? Exciting progress in electron EDM using molecules.
Several neutron EDM experiments under development to improve their sensitivity level.
Proton EDM could be decisive to clarify the picture.

42. Storage ring proton EDM method
All-electric storage ring. Strong radial E-field to confine protons with “magic” momentum. The spin vector is aligned to momentum horizontally.
High intensity, polarized proton beams are injected Clockwise and Counter-clockwise with positive and negative helicities. Great for systematics
Great statistics: up to ~1011 particles with primary proton beams and small phase-space parameters.

43. Large Scale Electrodes, New: pEDM electrodes with HPWR
Parameter
Tevatron pbar-p Separators
BNL K-pi Separators
pEDM
Length
2.6m
4.5m 3m
Gap
5cm
10cm
3cm
Height
0.2m
0.4m
Number 24 2
102
Max. HV
180KV
200KV
150KV

44. Physics reach of magic pEDM (Marciano)
Sensitivity to new contact interaction: 3000 TeV
Sensitivity to SUSY-type new Physics:
The proton EDM at 10-29e∙cm has a reach of >300TeV or, if new physics exists at the LHC scale, < rad CP-violating phase; an unprecedented sensitivity level.
The deuteron EDM sensitivity is similar. 44

45. The grand issues in the proton EDM experiment
BPM magnetometers (need to demonstrate in a storage ring environment)
Polarimeter development: high efficiency, small systematic errors
Spin Coherence Time (SCT): study at COSY/simulations; Simulations for an all-electric ring: SCT and systematic error studies
Electric field development for large surface area plates

46. 1. Beam Position Monitors
Technology of choice: Low Tc SQUIDS, signal at Hz (10% vertical tune modulation)
R&D sequence:
Operate SQUIDS in a magnetically shielded area-reproduce current state of art
Operate in RHIC at an IP (evaluate noise in an accelerator environment);
Operate in E-field string test

47. 2. Polarimeter Development
Polarimeter tests with runs at COSY (Germany) demonstrated < 1ppm level systematic errors: N. Brantjes et al., NIM A 664, 49, (2012)
Technologies under investigation:
Micro-Megas/Greece: high rate, pointing capabilities, part of R&D for ATLAS upgrade
MRPC/Italy: high energy resolution, high rate capability, part of ALICE development

48. 3. Spin Coherence Time: need >102 s
Not all particles have same deviation from magic momentum, or same horizontal and vertical divergence (all second order effects)
They cause a spread in the g-2 frequencies:
Present design parameters allow for 103 s. Cooling/mixing during storage could prolong SCT (upgrade option?).

49. The miracles that make the pEDM
Magic momentum (MM): high intensity charged beam in an all-electric storage ring
High analyzing power: A>50% at the MM
Weak vertical focusing in an all-electric ring: SCT allows for 103s beneficial storage; prospects for much longer SCT with mixing (cooling and heating)
The beam vertical position tells the average radial B-field; the main systematic error source

51. With coordinate mapping inversion

52. Tracking results
To achieve storage we had to “clip” the inner plates by theta~1mrad