Mitglied der HelmholtzGemeinschaft From COSY to a dedicated

Mitglied der Helmholtz-Gemeinschaft From COSY to a dedicated EDM storage ring July 7 -12 2014 | Ralf Gebel CGSWHP – Tbilisi, Georgia

Mitglied der Helmholtz-Gemeinschaft Outline § Introduction § JEDI approach for EDM measurements in storage rings § Beam and polarization preparation in the synchrotron § Developments towards a dedicated storage ring § Conclusion 4. November 2020 2

Results of EDM searches Only upper limits for EDM up to now (in e cm) Particle/Atom Current EDM Limit Future Goal Neutron 3 10 -26 10 -28 199 Hg 3. 1 10 -29 129 Xe 6 10 -27 10 -30 – 10 -33 Proton 7. 9 10 -25 10 -29 Deuteron ? 10 -29 Mitglied der Helmholtz-Gemeinschaft • Huge efforts underway to improve limits / find EDMs • It is important to measure neutron and proton, deuteron and light nuclei EDMs in order to disentangle various sources of CP violation 4. November 2020 3

Storage Ring EDM Project • • • … measure the development of vertical polarization Challenges: Step wise: EDM Huge E-fields . . . Shielding B-fields Spin coherence Beam position Polarimetry JEDI COSY (Po. F-III 2015 -2019) R&D for a dedicated storage ring, Precursor Expt. Goal: 10 -24 e∙cm Dedicated SR (2020++) Goal: 10 -29 e∙cm Mitglied der Helmholtz-Gemeinschaft Jülich Electric Dipole Moment Investigations ~ 100 members (Aachen, Bonn, Dubna, Ferrara, Cornell, Jülich, Krakow, Michigan, St. Petersburg, Minsk, Novosibirsk, Stockholm, Tbilisi, . . . ) 10 Ph. D students from JARA-FAME (Forces and Matter Experiments)

Search for Electric Dipole Moments Approach: EDM search in time development of spin in a storage ring: Mitglied der Helmholtz-Gemeinschaft “Freeze“ horizontal spin precession and watch for development of a vertical component ! A magic storage ring for protons (only electrostatic), deuterons (E + B), … particle p (Ge. V/c) E (MV/m) B (T) proton 0. 701 16. 789 0. 000 deuteron 1. 000 -3. 983 0. 160 3 He 1. 285 17. 158 -0. 051 One machine with r ~ 30 m 5

Thomas-BMT Equation for spin motion of relativistic particles in storage rings for . A. Magiera Mitglied der Helmholtz-Gemeinschaft The spin precession relative to the momentum direction is given by: Magnetic Moment 4. November 2020 Electric Dipole Moment 6

EDM Projects Light-Ion EDM Jülich Mitglied der Helmholtz-Gemeinschaft Proton EDM BNL R&D Activity Goal Test Internal Polarimeter spin as a function of time Systematic errors < 1 ppm EDM at COSY Full-scale polarimeter EDM at COSY Spin Coherence Time >103 s EDM at COSY Beam Position Monitor resolution 10 nm, 1 Hz BW 64 BPMs, 107 s measurement time 1 ppm (stat. ) relative position (CW-CCW) BNL RHIC IP EB-field Deflector 17 MV/m 2 cm plate separation, 0. 15 -0. 5 T Jülich 7

Timeline for the stepwise approach all-in-one machine for JEDI Step Aim / Scientific goal Device / Tool Storage ring Spin coherence time studies Horizontal RF-B spin flipper COSY Systematic error studies Vertical RF-B spin flipper COSY upgrade Orbit control, magnets, … COSY 2 First direct EDM measurement RF-Ex. B spin flipper, static devices Modified COSY 3 Built dedicated all-in-one ring for p, d, 3 He Common magneticelectrostatic deflectors 4 EDM measurement of p, d, 3 He Mitglied der Helmholtz-Gemeinschaft 1 Dedicated ring 8

Status - COSY Cooler and storage ring for (polarized) protons and deuterons p = 0. 3 – 3. 7 Ge. V/c Mitglied der Helmholtz-Gemeinschaft Phase space cooled internal & extracted beams Injector cyclotron COSY e-Cooler … provides excellent equipment for spin physics with hadron beams 9

EDM: Prototyping and Spin Physics Prototype Polarimeter RF Ex. B Spin Flipper S. Mey F. Hinder Electrostatic Deflector SQUID and Cavity BPMs Mitglied der Helmholtz-Gemeinschaft H. Soltner Polarized Ion source Beam and Spin Dynamics Siberian Snake (2015) A. Pesce, A. Magiera EDM/JEDI accelerator and detector component tests

R&D for Hadron Storage Rings Mitglied der Helmholtz-Gemeinschaft Topics (with FZJ as leading lab) • (polarized) Ion sources for hadron storage rings • Assure high intensity beams for COSY • Possible later experiments at FAIR with polarized beams • Combined electrostatic and magnetic deflectors • Search for an electric dipole moment in p, d and He 3 • High energy beam cooling and broad band stochastic cooling • Electron cooling up to COSY’s maximum momentum • Electron cooling for HESR • Fast stochastic cooling at different energies 11

ARD topic: (pol. ) Ion source development Atomic beam studies • Intensity • Density, profiles • Velocity distribution Cs beam studies Plasma ionizer Mitglied der Helmholtz-Gemeinschaft • Intensity • Profile/ Brightness Beam diagnostics • Polarization 12

COSY‘s Polarized Ion Source 1150 K 550 K RF discharge Thermal ionizer Mitglied der Helmholtz-Gemeinschaft 38 K Charge exchange reaction H 0(D 0) + Cs 0 H-(D-) + Cs+ Ref. : Haeberli , NIM 62(1968) 13

Performance (Reference values) Pavg = (91. 4 2. 2 ) % Data from Exp. EDDA Mitglied der Helmholtz-Gemeinschaft (pp – elastic scattering) Beam current at the source exit* *compare Polarization inside COSY to routine COSY fill of a few 1010 protons or deuterons (space charge limit of about 1011) 14

Polarimetry: from source to experiment Mitglied der Helmholtz-Gemeinschaft LEP P Ring EDDA Test Pol • Breit Rabi Polarimetry • 4. 5 ke. V/u Polarimetry • 45 Me. V/u Polarimetry

The COSY Injector with Ion Sources Lamb shift Spare solenoid: Mitglied der Helmholtz-Gemeinschaft Wien filter Beam rotator

Mitglied der Helmholtz-Gemeinschaft The cyclotron AEG design Request for quote: 1961 First internal beam: 1968 Pole diameter 3. 3 m / 700 t iron <B>max =1. 35 T Bhill = 1. 97 T Frequency range 20 – 30 MHz (h=3) Energy 22. 5 -45 Me. V/A Injection 2 -4. 5 ke. V/A 3 ion sources (2 multicusp +pol. CBS) AEG cyclotron 17

Frequency [MHz] The cyclotron - - 3 He+ • Provides polarized H and D • Proven operation for light ions • 3 + He possible (1/2 B 0 for 6 th harmonic) D- H- Mitglied der Helmholtz-Gemeinschaft Working area of JULIC Energy/nucleon [Me. V] AEG cyclotron Cyclotron‘s working area (3 rd harmonic) 18

Mitglied der Helmholtz-Gemeinschaft Status: COSY and Cyclotron Operation Availability (Up time) of the injector cyclotron 19

Prototyping and Tests with COSY is the technical platform for JEDI and HESR R&D COSY Facility: Developments Electron Cooler Barrier Bucket Cavity mean energy loss compensation 100 k. V Pellet Target beam-target interaction Mitglied der Helmholtz-Gemeinschaft COSY: 0. 3 -3. 7 Ge. V/c Pol. protons and deuterons Stochastic Cooling Beam and Spin Dynamics 4. November 2020 Residual Gas Profile Monitor Electron Cooler 2 MV 20

COSY Electron Cooler Electron Energy: < 100 k. V (24. 5 k. V) Electron Current: < 4 A (200 m. A) Beam Current Mitglied der Helmholtz-Gemeinschaft e. g. Beam Accumulation at Injection Time

New installations Mitglied der Helmholtz-Gemeinschaft 2 Me. V Electron Cooler, together with BINP/Novosibirsk 22

2 Me. V Electron Cooler Joint development with Budker Institute (BINP, Russia), commissioned at COSY, injection cooler for HESR Parameters demonstrated so far: • Voltage up to 1. 5 MV (5 bar SF 6) • Cooling at 900 k. V / 300 m. A (1. 8 Ge. V p) • Ongoing: commissioning for full COSY energy range (3 Ge. V) radial Mitglied der Helmholtz-Gemeinschaft Amplitude vertical After Before y (mm) After Before 200 Me. V p x (mm) Cooperation partners: BINP, JINR, FZJ, HIM 23

COSY Stochastic Cooler • 2 Pickup tanks, 4 m long (cooled to 20 K) 2 Kicker tanks, 2 m long • Frequency range: • – 1. 0 -1. 8 GHz – 1. 8 -3. 0 GHz Mitglied der Helmholtz-Gemeinschaft Pickup • Adjustable delays for different ion velocities above β=0. 85 • Installed RF power plane: 500 W • Longitudinal filter cooling: Notch Filter utilizing vertical system in „sum mode“ and To. F cooling Kicker 24

Example: Beam Cooling with WASA Pellet Target Mitglied der Helmholtz-Gemeinschaft a) b) c) d) Injected beam Beam heated by target + stochastic cooling + barrier bucket

Technogical challenges for sr. EDM search Charged particle EDM searches require development of a new class of highprecision machines with mainly electric fields for bending and focussing. Related topics: • Electric field gradients (~17 MV/m at 2 cm) • Spin coherence time (>1000 s) • Continuous polarimetry (< 1 ppm) Mitglied der Helmholtz-Gemeinschaft • Beam positioning (10 nm) in the following talks • Spin tracking These issues are addressed experimentally at COSY 26

Search for Electric Dipole Moments Approach: EDM search in time development of spin in a storage ring: Mitglied der Helmholtz-Gemeinschaft “Freeze“ horizontal spin precession and watch for development of a vertical component ! A magic storage ring for protons (only electrostatic), deuterons (E + B), … particle p (Ge. V/c) E (MV/m) B (T) proton 0. 701 16. 789 0. 000 deuteron 1. 000 -3. 983 0. 160 3 He 1. 285 17. 158 -0. 051 One machine with r ~ 30 m 27

Challenge: Electric field for magic rings Mitglied der Helmholtz-Gemeinschaft 5 m. 2 L~ July 2014: Transfer of separator parts plus equipment from FNAL to Jülich Need to develop new electrode materials and surface treatments 28

Jülich All-In-One Ring Lattice Mitglied der Helmholtz-Gemeinschaft Iron-free, current-only, magnetic bending, eliminates hysteresis achievable field of copper magnets of ~ 0. 15 T.

An iron free deflector R. Talman’s design proposal – Landau-Lifschitz: • analytic model • Numerical model • Prototype – Technical issues Mitglied der Helmholtz-Gemeinschaft • Field quality • Thermal load, cooling • Precision 30

Development steps Mitglied der Helmholtz-Gemeinschaft from Landau Lifschitz towards a real magnet 31

Outlook: Cooler Synchrotron as COSY EDM injector Siberian Snake Ions: (pol. & unpol. ) p and d 2 MV Electron Cooler Momentum: 300/600 to 3700 Me. V/c for p/d, respectively Circumference of the ring: 184 m Electron Cooling at injection Mitglied der Helmholtz-Gemeinschaft Stochastic Cooling above 1. 5 Ge. V/c Injection into EDM ring: Longitudinal polarized, pre-cooled beam single bunch or bunch into bucket injection

Siberian Snakes Full Siberian Snake: = 180° νsp = ½ Spin manipulation or snake fields: Mitglied der Helmholtz-Gemeinschaft longitudinal fields (solenoids) at lower energies transverse fields (helical dipoles) at higher energies Full Siberian snake for 1 Ge. V/c: 3. 75 Tm (protons), 12. 24 Tm (Deuterons) Superconducting 4. 7 Tm solenoid is ordered. Overall length: 1 m Ramping time 30 s Installation at COSY in spring 2015

Conclusion COSY provides needed tools for sr. EDM studies • Polarized beams from the cyclotron • Cooled beams • Spin manipulators, targets and detectors § New features § Improved/ new beam diagnostics -> BPM, Squids § Polarimeter -> turn-by-turn, efficiency § Next things to do § Longitudinal spin preparation -> Snake § High field deflectors -> FNAL separators § Light ion sources -> He 3 § Design of the dedicated storage ring … and more Mitglied der Helmholtz-Gemeinschaft § 4. November 2020 34

Mitglied der Helmholtz-Gemeinschaft Thank you for your attention … and many thanks to A. Lehrach, F. Rathmann and others for their templates 35

4. November 2020 Spares 36 Mitglied der Helmholtz-Gemeinschaft

Challenge: Spin coherence time Spin closed orbit one particle with magnetic moment makes one turn “spin closed orbit vector” “spin tune” stable polarization ring Mitglied der Helmholtz-Gemeinschaft A if ║ 37

Challenge: Spin coherence time Polarization not affected! At injection all spin vectors aligned (coherent) After some time, spin vectors get out of phase and fully populate the cone Mitglied der Helmholtz-Gemeinschaft Longitudinal polarization vanishes! At injection all spin vectors aligned Later, spin vectors are out of phase in the horizontal plane 38

Spin Precession Spin precession for particles at rest in electric and magnetic fields: (* rest frame) In a real neutral particle EDM experiment for non-relativistic particles, the spin precession is given by: Ideal vertical B-Fields and horizontal E-Fields: Mitglied der Helmholtz-Gemeinschaft EDM signal Systematic error Equation for spin motion of relativistic particles in storage rings more complicated

Frozen Spin Method (FSM) Spin vector Momentum vector Mitglied der Helmholtz-Gemeinschaft Spin coherence time: 103 s for measurement on 10 -29 e·cm level Lower energy particle …just right Higher energy particle , the spin precession (magnetic moment) For relative to the momentum direction is given by