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Frascati, 5 October 2005. Methods of E lectric D ipole M oments in Storage Rings. Yannis K. Semertzidis Brookhaven National Lab. Parasitic to g-2 Frozen spin Resonance. Experimental Principle of g-2 or EDM:. Polarize Interact: Analyze as a function of time. in a B or E-Field. - PowerPoint PPT Presentation
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EdBdt
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Methods of Electric Dipole Moments in Storage Rings
Yannis K. Semertzidis
Brookhaven National Lab
Frascati, 5 October 2005
•Parasitic to g-2•Frozen spin•Resonance
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Experimental Principle of g-2 or EDM:
• Polarize
• Interact:
• Analyze as a function of time
in a B or E-Field
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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The Principle of g-2
Spin vector Non-relativistic case
• B
m
eBc
m
eBgs 2
m
eBa
m
eBg
m
eB
m
eBgacsa
2
2
2
Momentum vector
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Spin Precession in g-2 Ring(Top View)
Bm
eaa
Momentumvector
Spin vector
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Effect of Radial Electric Field
• Low energy particle
• …just right
• High energy particle
Spin vector
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Effect of Radial Electric Field
• …just right
Spin vector
, 29.3
for muons
(~3GeV/c)
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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• The Muon Storage Ring: B ≈ 1.45T, Pμ ≈ 3 GeV/c
•High Proton Intensity from AGS
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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4 Billion e+ with E>2GeV
aa
t
tAeNdtdN
cos1/ 0
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Electric Dipole Moments in Storage Rings
e.g. 1T corresponds to 300 MV/m for relativistic particles
Buddt
sd
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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B
a edm
Ron McNabb’s Thesis 2003: C.L. 95% cme107.2 19
x
y
z
sβ
aω
edm
m
e Ba
Buc
2
Indirect Muon EDM limit from the g-2 Experiment
a
edm
tan
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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The Vertical Spin Component Oscillates due to EDM
Time 8 s
Ver
tica
l Sp
in C
omp
o ne n
t a.
u.
0 s
g-2 period
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Effect of Radial Electric Field
• Low energy particle
• …just right
• High energy particle
Spin vector
Momentum vector
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Use a Radial Electric Field and a
• Low energy particleSpin vector
Momentum vector
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Spin Precession in g-2 Ring(Top View)
Bm
eaa
Momentumvector
Spin vector
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Spin Precession in EDM Ring(Top View)
0a
Momentumvector
Spin vector
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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(U-D)/(U+D) Signal vs. Time
(U-D
)/( U
+D
)
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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B
a edmx
y
z
sβ
aω
edm
m
e Ba
Buc
2
a
edm
tan
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Vertical Spin Component without Velocity Modulation (deuterons)
Time
Ver
tica
l Sp
in C
omp
o ne n
t a.
u.
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Velocity Modulation in Phase with g-2 Precession
Vel
ocit
y-0.
35
Time [ns]
g-2 Precession
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Vertical Spin Component with Velocity Modulation at a
Ver
tica
l Sp
in C
omp
o ne n
t a.
u.
Time
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Vertical Spin Component with Velocity Modulation (longer Time)
Ver
tica
l Sp
in C
omp
o ne n
t a.
u.
75 s Time 0 s
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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EDM Spin Resonance MethodSome of Y. Orlov’s main ideas:
• Synchrotron tune = (a-N), a=(g-2)/2, N=0,1,2,…
• Cancel systematics by the two half beam storage at different vertical tunes
• Use n=1 in the dipole magnets, and p=1 mainly to keep the phase of the g-2 rotation linear with t.
• D-function0 at straight section…
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Two half beam technique
See talk by B. Morse tomorrow
This tune makes its spin more sensitiveto background
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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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.
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Storage Ring EDMs
• Interesting Physics
• Study the ideas, improve design
• Contribution level to this effort
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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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
Frascati, 5 October 2005 Yannis Semertzidis, BNL EdBdt
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Nuclear Scattering as Deuteron EDM polarimeter
IDEA:- make thick target defining aperture- scatter into it with thin target
D
L
U
R
R
DΔ
“extraction”target - ribbon
“defining aperture”primary target
detectorsystem
Target could beAr gas (higher Z).
Target “extracts” byCoulomb scattering deuterons onto thickmain target. There’snot enough goodevents here towarrant detectors.
Hole is largecompared tobeam. Every-thing that goesthrough holestays in thering.
Detector is far enoughaway that doughnutillumination is not anacceptance issue:Δ < R.
Ed Stephenson’s
Alternative way: resonant slow extraction (Y. Orlov)
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