8 March 2018 CPEDM meeting Juelich Status of

8 March 2018 CPEDM meeting, Juelich Status of Storage Ring EDM Yannis Semertzidis, CAPP/IBS and KAIST The view from Korea • Keep it simple, prioritize with proton • Precision physics frontier, great physics reach, probing NP ~103 -104 Te. V • R&D critical phase coming together, getting ready to design a functional ring 1

Review of Scientific Instruments 87, 115116 (2016) 2

The proton EDM electric ring, 500 m circ. Straight sections are instrumented with quads, BPMs, polarimeters, injection points, etc, as needed. Requirements: Weak vertical focusing (B-field sensitivity) Below transition (reduce IBS) 3

Critical R&D projects • SQUID-based BPMs, at <10 f. T/sqrt(Hz) level • Characterize its functionality, time stability • Magnetic field shielding <10 n. T • Geometrical phases: 1. magnetic, 2. electric • Study with precision simulation tools • Clearly define lattice elements specs, what is possible with beam-based alignment 4

Critical R&D projects, con’d • Develop a robust polarimeter: deadtime-less, point back to origin, high efficiency, high analyzing power • Have an answer: what else can we do with this facility? Axion-dark matter: Axion-EDM project • Reliable, cheap E-bending plates: Ti. N-coated aluminum plates (follow J-LAB work & scale up) 5

JLab results with Ti. N-coated Aluminum No measureable field emission at 225 k. V for gaps > 40 mm, happy at high gradient Matt Poelker, JLab Bare Al Ti. N-coated Al We need <10 MV/m for 30 mm plate separation 15 MV/m 20 MV/m the hard coating covers defects Work of Md. A. Mamun and E. Forman 6

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Projects in Korea • Magnetic field shielding, SQUID-based BPMs, IBS/CAPP, KRISS, TUM, … • Teamleader: Selcuk Haciomeroglu • Goal: develop a SQUID-based BPM at the 110 f. T/sqrt(Hz) level • Characterize it at IBS/CAPP for time stability • Install it at a ring for real-time testing 8

Projects in Korea • Schedule, SQUIDs: 1 full scale unit ready for testing at IBS/CAPP: fall 2018. • Ready for installation for testing at a storage ring in 2019 9

Beam position monitor: SQUID array Liquid He Vacuum SQUID magnetometer To p-beam line 10

Cylindrical Dewar: under fabrication 11

SQUID-based BPM development Subjects Category 2014 2015 2016 2017 SQUID magnetometer and control electronics system Pretest SQUID system Low-noise SQUID system for p. EDM Research outcome 2018 2019 Ultra-low-noise SQUID magnetometer and control electronics system Hollow cylindrical dewar, Superconductive shielding, optimization 16 ch SQUID system optimization 8 -ch SQUID system, 3 f. T/Hz 16 ch SQUID system, system noise 3 f. T/√Hz (@ 1 k. Hz) System noise 2 f. T/√Hz 1. 5 f. T/√Hz (@ 1 k. Hz) 12

Projects in Korea • Schedule, Magnetic shielding: 1 full scale unit under test at IBS/CAPP. • Improve shielding factor of magnetic shielding room in 2018 • Finish time stability tests in 2019 13

Selcuk Haciomeroglu, Andrei Matlashov et al. Two-layered system, time drift tests limited by environmental noise Achieved so far: Absolute field: <10 n. T, limited by gradients and drifts Improving our shielding room to study the effects… 14

Projects in Korea • Precision beam and spin dynamics • Teamleader: Selcuk Haciomeroglu • Goal: establish specs of lattice elements (2018) • Schedule: work with Martin Gaisser et al. , in monthly beam/spin dynamics meetings • Work with Sieg Martin towards a practical lattice 15

Projects in Korea • Polarimeter-related systematic errors • Teamleader: Seong. Tae Park • Goal: implement a reliable spin dependent cross section in GEANT 4 for systematics studies • Collect the proton polarimetry data at COSY • Develop a reliable, GEM-based polarimeter for sr. EDM exps. • See talk by Seong. Tae Park on March 6 16

Projects in Korea • Axion-EDM project • Teamleader: Seong. Tae Park • Goal: establish best sensitivity to generic axion dark matter for low frequency range • Axion oscillation frequency on resonance with g -2 frequency of proton/deuteron • Use current COSY ring for <30 MHz range (even RF-Wien filter works with less sens. ) 17

Electric Dipole Moments in Magnetic Storage Rings e. g. 1 T corresponds to 300 MV/m for relativistic particles 18

Indirect Muon EDM limit from the g-2 Experiment z B y s β x Ron Mc. Nabb’s Thesis 2003: 19

Horizontally there’s a g-2 precession and vertically a regular spin buildup (axion/g-2 resonance) 20

Projected experimental sensitivity 21

Systematic errors (or how do we do the experiment!) • Vast literature available from the sr. EDM collaboration web sites: • • What cancels CW vs. CCW (1996) Spin Coherence Time (Yuri Orlov, 2000 -2004) Clock wise (CW) and Counter CW stores Corrugated particle orbits aka “Twist” and “Saucer” effects (2002, 2003) 22 • Geometrical phases (2002)

Toolkit against systematic errors • CW vs. CCW (advantage: proton EDM ring is at same time) • Positive vs. negative helicity for polarimeter systematic errors • Spin at radial direction to maximize effects from distortions (no EDM effect) 23

Lattice and systematic errors • Some lattices are (much) better than others! • Best (for systematic errors): continuous weak focusing machine • Next best: focusing and E-field bending at same location • Next next best: separate (soft vertical) focusing and E-field bending • Next next best: separate (strong vertical) focusing and E-field bending. Do not despair!24

Putting together the experiment • Mechanically place all elements to 0. 1 mm local resolution (or as well it is possible) • Using button BPMs (or Rogowski coils, TBD) to achieve resolution at the 1 micron level (Tim Wagner you have a secure job!) • Run the experiment with 90 & 180 degrees (radial) spin direction. Use vertical E-field trim plates around the ring to cancel the effect of 25 distortions

Running the experiment • Modulate the quads by somewhere between 110% all at same frequency (for SQUID-based BPMs) • Modulate each quad at its own freq. by 0. 1%. • Use the radial spin direction bunches to keep system aligned with trim E-fields • Use SQUIDs or longitudinal spin direction bunches to keep the average radial B-field to 26 zero

New by Yu. Senichev: Running the experiment • Under certain conditions CW vs. CCW cancels ring distortions. (Note: Not all!) • We will work with Yu. Senichev to come up with a possible lattice to use the Frequency Domain Method • Possible advantages (need to confirm): SCT; Some forms of Geometrical phases • Still need low vertical focusing to cancel radial B 27 -field effects

Yu. Senichev’s slide 28

Summary • The physics of the storage ring EDMs is strong. Now even stronger • Keep it simple, start with proton, all electric ring • Critical items are mature and ready for prime time: SQUID-based BPMs, magn. shielding, GEANT 4 & Polarimetry, Axion-EDM • Precision beam/spin dynamics simulations to help finalize the lattice designs • Write-up on systematic errors by end of 2018. 29

Extra slides 30

Yu. Senichev’s slide 31

Storage ring EDM: The proton • • • High intensity sources (~1011/fill) High vector polarization (>80%) High analyzing power for 0. 7 Ge. V/c (233 Me. V) Long spin coherence time possible (>103 s) Simultaneous CW & CCW storage 32

Proton Statistical Error (230 Me. V): τp : 103 s Polarization Lifetime (Spin Coherence Time) A : 0. 6 Left/right asymmetry observed by the polarimeter P : 0. 8 Beam polarization Nc : 1011 p/cycle Total number of stored particles per cycle TTot: 107 s Total running time per year f : 1% Useful event rate fraction (efficiency for EDM) ER : 7 MV/m Average radial electric field strength σd = 1. 0× 10 -29 e-cm / year 33

Peter Fierlinger, Garching/Munich Under development by Selcuk Haciomeroglu at CAPP. Need absolute field: few n. T Need gradient field: ~n. T/m 34

Proton systematic errors case 1. Main systematic error (radial B-field) is well under control: measure dsv/dt and vertical split of beams at 1 k. Hz. 2. Geometrical phase for B-field: CW vs CCW cancel! 3. B-field shielding: few n. T, well under control 4. E-field specs: 100μm placement, 10μm using beam based alignment? 35

Status 1. Proton systematic error studies show great promise, coming to conclusions soon. 2. Deuteron questions: 1. Ev stability, including when B-field is reversed 2. Level of local cancellation with mixed E and B-fields (Geometrical phases) 3. Patch effect from E-field plate surfaces. 4. Complications from Tensor polarization? 36

Spin Coherence Time: need ~103 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. • Much longer SCT with thermal mixing (S. C. )? 37

Technically driven p. EDM timeline 2015 16 17 18 19 20 21 22 23 24 • Research and systems development (R&D); CDR; final ring design, TDR, installation • CDR end of 2018 • Proposal to a lab: fall 2020 38

Geometrical Phases in Deuteron EDM Example from the proton case: S s t e h t ra t c tri … s c e p s s r e 39

Geometrical Phases in Deuteron EDM Ground motion: Coherence up to 90 -120 m apart. 40

Geometrical Phases in Deuteron EDM Ground motion: FNAL MINOS hall 41

Geometrical Phases in Deuteron EDM Ground motion: FNAL MINOS hall 42

1. Symmetries 43

2. Specs a) Leakage currents: <1μA b) Power Supply stability (on average): <10 -4 c) Net heat source in enclosed ring: <(± 20 kwatt) d) Average field uniformity over 2 cm diameter: ~1 ppm 44