The Storage Ring Proton EDM experimentYannis 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.

23 July 2014Lepton Moments, Cape Cod

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

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

http://capp.ibs.re.kr/html/capp_en/CAPP Group

Three more Research Fellows signed up already…

Storage Ring Proton EDM

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

Yannis Semertzidis, CAPP/IBS, KAIST

Stored beam: The radial E-field force is balanced by the centrifugal force.

E

E E

E

Yannis Semertzidis, CAPP/IBS, KAIST

The proton EDM uses an ALL-ELECTRIC ring: spin is aligned with the momentum vector

0a

Momentumvector

Spin vector

E

E E

E

at the magic momentum

mp

a

The proton EDM ring

Total circumference: 300 m Bending radius: 40 m

Straight sections are instrumentedwith quads, BPMs, polarimeters,injection points, etc, as needed.

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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 1953-57– It worked!

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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

The proton EDM ring evaluation Val Lebedev (Fermilab)

Beam intensity 1011 protons limited by IBS

, kV

Extraction: lowering the vertical focusing

“defining aperture”polarimeter target

RL

RLH

UD

UDV

carries EDM signalincreases slowly with time

carries in-plane (g-2) precession signal

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.

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

The EDM signal: early to late change• Comparing the (left-right)/(left+right) counts vs.

time we monitor the vertical component of spin

(L-R)/(L+R) vs. Time [s]

M.C. data

Opposite helicity bunchesresult to opposite sign slopes

Large polarimeter analyzing power at Pmagic!

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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),…)

Clock-wise (CW) & Counter-Clock-wise Storage

Equivalent to p-bar p colliders inMagnetic rings

Any radial magnetic field sensed by the stored particles will also cause theirvertical splitting. Unique feature among EDM experiments…

Distortion of the closed orbit due to Nth-harmonic of radial B-field

Y(ϑ)

Time [s]

Clockwise beam

Counter-clockwise beam

The N=0 componentis a first order effect!

Vertical tune modulation frequency: 10 kHz

Noise level: 0.9 fT/√Hz

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SQUID gradiometers at KRISS

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SQUID gradiometers at KRISS

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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!

Peter Fierlinger, Garching/Munich

Issues: demagnetization,effect of holes, etc.

Peter Fierlinger, Garching/Munich

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International srEDM NetworkCommon 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• …

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.

The radial position away from the ideal orbit as a function of ring X and Y coordinates.

Tracking results using realistic (analytic estimations of) fringe fields

E. Metodiev et al.,to appear in PRSTAB

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

0 50 100 150 200 2500

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Single crystal niobium

Field Emission from Niobium

Conventional High Voltage processing: solid data pointsAfter Krypton Processing: open data points

Work of M. BastaniNejadPhys. Rev. ST Accel. Beams, 15,

083502 (2012)

Field strength > 18 MV/m

Buffer chemical polish: less time consuming than diamond paste polishing

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

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Technically driven pEDM timeline

• Two years system development• One year final ring design• Three years beam-line construction and

installation

13 14 15 16 17 18 19 20 21 22

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pEDM in all electric ring in the USA Jülich, focus on deuterons, or a combined machine

CW and CCW propagating beams

EDMs: Storage ring projects

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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.

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The JEDI experiment statusHelmholtz 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.

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 10-29 ecm with a final goal 10-30

ecm. Complementary to LHC; probes New Physics ~102-103 TeV.

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Extra slides

Peter Fierlinger, Garching/Munich

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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.

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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.

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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 0.2m

Number 24 2 102

Max. HV 180KV 200KV 150KV

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Physics reach of magic pEDM (Marciano)

The proton EDM at 10-29e∙cm has a reach of >300TeV or, if new physics exists at the LHC scale, <10-7-10-6 rad CP-violating phase; an unprecedented sensitivity level.

The deuteron EDM sensitivity is similar.

• Sensitivity to SUSY-type new Physics:

• Sensitivity to new contact interaction: 3000 TeV

10 13 Currently: 10 , Sensitivity with pEDM: 0.3 10

2

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SUSY

1TeV10 e cm sinpEDM

M

The grand issues in the proton EDM experiment

1. BPM magnetometers (need to demonstrate in a storage ring environment)

2. Polarimeter development: high efficiency, small systematic errors

3. Spin Coherence Time (SCT): study at COSY/simulations; Simulations for an all-electric ring: SCT and systematic error studies

4. Electric field development for large surface area plates

1. Beam Position Monitors

• Technology of choice: Low Tc SQUIDS, signal at 102-104Hz (10% vertical tune modulation)

• R&D sequence:

1. Operate SQUIDS in a magnetically shielded area-reproduce current state of art

2. Operate in RHIC at an IP (evaluate noise in an accelerator environment);

3. Operate in E-field string test

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:

1. Micro-Megas/Greece: high rate, pointing capabilities, part of R&D for ATLAS upgrade

2. MRPC/Italy: high energy resolution, high rate capability, part of ALICE development

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?).

22 2

a x y

dPd a b c

P

The miracles that make the pEDM1. Magic momentum (MM): high intensity

charged beam in an all-electric storage ring

2. High analyzing power: A>50% at the MM

3. Weak vertical focusing in an all-electric ring: SCT allows for 103s beneficial storage; prospects for much longer SCT with mixing (cooling and heating)

4. The beam vertical position tells the average radial B-field; the main systematic error source

With coordinate mapping inversion

Tracking results

• To achieve storage we had to “clip” the inner plates by theta~1mrad