Methods of Electric Dipole Moments in Storage Rings

1
Methods of Electric Dipole Moments in Storage
Rings
Frascati, 5 October 2005

• Yannis K. Semertzidis
• Brookhaven National Lab

• Parasitic to g-2
• Frozen spin
• Resonance

2
Experimental Principle of g-2 or EDM

• Polarize
• Interact
• Analyze as a function of time

in a B or E-Field
3
The Principle of g-2

• Non-relativistic case

Spin vector
Momentum vector
B
4
Spin Precession in g-2 Ring(Top View)
Momentum vector
m
Spin vector
5
Effect of Radial Electric Field
Spin vector

• Low energy particle
• just right
• High energy particle

6
Effect of Radial Electric Field
Spin vector

• just right

, ??29.3 for muons (3GeV/c)
7

• The Muon Storage Ring B 1.45T, Pµ
  3 GeV/c

• High Proton Intensity from AGS

8
4 Billion e with Egt2GeV
9
Electric Dipole Moments in Storage Rings

• e.g. 1T corresponds to 300 MV/m for
  relativistic particles

10
Indirect Muon EDM limit from the g-2 Experiment
B
Ron McNabbs Thesis 2003
11
The Vertical Spin Component Oscillates due to EDM
Vertical Spin Component a.u.
g-2 period
8 ?s
Time
0 ?s
12
Effect of Radial Electric Field
Spin vector

• Low energy particle
• just right
• High energy particle

Momentum vector
13
Use a Radial Electric Field and a
Spin vector

• Low energy particle

Momentum vector
14
Spin Precession in g-2 Ring(Top View)
m
15
Spin Precession in EDM Ring(Top View)
m
16
(U-D)/(UD) Signal vs. Time
(U-D)/(UD)
17
B
18
Vertical Spin Component without Velocity
Modulation (deuterons)
Vertical Spin Component a.u.
Time
19
Velocity Modulation in Phase with g-2 Precession
Velocity-0.35
Time ns
g-2 Precession
20
Vertical Spin Component with Velocity Modulation
at ?a
Vertical Spin Component a.u.
Time
21
Vertical Spin Component with Velocity Modulation
(longer Time)
Vertical Spin Component a.u.
75 ?s
Time
0 ?s
22
EDM Spin Resonance MethodSome of Y. Orlovs main
ideas

• Synchrotron tune (a?-N), a(g-2)/2, N0,1,2,
• Cancel systematics by the two half beam storage
  at different vertical tunes
• Use n1 in the dipole magnets, and ?p1 mainly to
  keep the phase of the g-2 rotation linear with t.
• D-function?0 at straight section

23
Two half beam technique
This tune makes its spin more sensitive to
background
See talk by B. Morse tomorrow
24
Other Issues

• Spin coherence time. I.B. Vasserman et al.,
  Phys. Lett. B198, 302 (1987) A.P. Lysenko, A.A.
  Polunin, and Yu.M. Shatunov, Particle
  Accelerators 18, 215 (1986).
• RF-system frequency, shape, strength, normal/SC.
  Is partial linearization needed? C. Ohmori, et
  al., 14th Symposium on Accelerator Science and
  Technology, Tsukuba, Japan, Nov. 2003 M.
  Yamamoto et al., PAC99.

25
Storage Ring EDMs

• Interesting Physics
• Study the ideas, improve design
• Contribution level to this effort

26
Summary

• end of the year Letter of Intent
• We need help to develop the final ring lattice
  and tolerances on parameters
• Goal for a proposal by the end of next year
• A unique opportunity for a significant
  contribution to the physics of EDM

27
Nuclear Scattering as Deuteron EDM polarimeter
Ed Stephensons

• IDEA
• make thick target defining aperture
• scatter into it with thin target

detector system
Alternative way resonant slow extraction (Y.
Orlov)
U
defining aperture primary target
L
extraction target - ribbon
R
D
R
?
D
Target could be Ar gas (higher Z).
Detector is far enough away that
doughnut illumination is not an acceptance
issue ? lt R.
Hole is large compared to beam. Every- thing
that goes through hole stays in the ring.
Target extracts by Coulomb scattering
deuterons onto thick main target. Theres not
enough good events here to warrant detectors.