COSY Step 1 Spin coherence and systematic error studies Proposal 2161 February 24 2014 Frank Rathmann on behalf of JEDI 42 nd Meeting of the COSY ID: 250200
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Slide1
Search for Permanent Electric Dipole Moments at COSYStep 1: Spin coherence and systematic error studies(Proposal 216.1)
February 24, 2014 Frank Rathmann on behalf of JEDI42nd Meeting of the COSY Programm Advisory Committee Slide2
IntroductionPresent proposal merges activities from #176 and #216 under
the flag of JEDI.Aim: Use expertise of both groups to develop instrumentation and techniques for EDM searches at storage rings.f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY2Slide3
Outline
Three recent achievementsProposed experimental investigations:Spin coherence time studies (contin. of #176)
RF
Wien F
ilter
Systematic
study of machine imperfections using
two straight
section solenoids Beam request
3
Search for Permanent Electric Dipole Moments at COSY
f.rathmann@fz-juelich.deSlide4
A 1: Spin coherence timef.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY
4Sextupole
corrections
of
higher
order
effects yield
Slide5
A 2: Spin tune determinationf.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY
5Using time
stamping
technique
from
Up
/Do asymmetry
Spin
tune
determined to
in
.
Average
in one cycle (
) known to
.
U
nderstand
implications
for
future
precision
experiments
. Slide6
A 3: Harmonic dependence of
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY6
Spin
coherence
time (s)
235
MeV
Beam
energy
(
MeV
)
O
bservation
of
enhancements
of
for
p (
and
d)
requires
more
flexible polarimeter
Theory
:
N.N.Nikolaev
Observed
oscillating
, driven
by
RF
solenoid
at different
harmonics
Slide7
1. Spin coherence time studies (contin. of #176)
Removing spin tune spread with sextupole fields:Observe result in lifetime (SCT) of horizontal polarizationMajor run in weeks 35 and 36 (August/September) 2013 (lots of data)
f.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY
7
Example of data measured with the time-marking
DAQ system
HORIZONTAL POLARIZATION
SCT
signs changed to
show linear effect
black = spin down
blue = spin up
Zero crossing of inverse slope locates best SCT.
Initial Polarization
SlopeSlide8
First 2-D Map: vs MXS vs MXG
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY8
MXG
MXS
0
20
20
40
+
+
+
+
+
+
+
+
+
+
+
Best SCT points for large horizontal
emittance
+
Best SCT points for large
Δ
p/p (longitudinal)
+
+
+
+
+
Units: percent
of power supply full scale.
ξ
X
= 0
ξ
Y
= 0
Location of best SCT is closely associated with location of vanishing chromaticity.
Each
sextupole
field
scan
locates
one
point
on 2D
map
Beam set up to emphasize different sources of
decoherence
, which can be corrected with
sextupole
fields.Slide9
Chromaticity studies (tests in week 7)f.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY9Chromaticity defines the tune change
with
respect
to
momentum
deviation Strong connection
between
and
observed
.
COSY
Infinity
based
model
predicts
negative
natural
chromaticities
and .Measured natural chromaticity:
and
changed
from
1
to
3 in 2013,
although
similar
machine
settings
were
used
.To
be studied:Vary sextupoles of arcs and straights: benchmark changes in model.Vary quadrupoles and orbit excitations to search for sources of variations.
Examine long term stability
.Ramp up dipole magnets to investigate influence of machine history on
.
Slide10
Measurement of
chromaticityTwo methods for beam energy shift appliedVariation
of
electron
cooler
voltage
Variation
of
cavity frequencyTune measurement:Sweep frequency
for beam excitation
and
measure response
to
locate
betratron
frequency
Measure
revolution
frequency
using
Schottky spectrumHorizontalVertical
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY
10Slide11
Chromaticity: A
rc sextupoles Three families in the arcs: (MXS, MXL, MXG)Non-vanishing dispersion
in
the
arcs
,
large
influence
of chromaticity expectedMeasurement / Model (change
per %)MXS:
/
/
MXL:
/
/
MXG:
/
/
f.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY
11Slide12
Chromaticity: Straight
section sextupoles Test of combined familiy of four straight section
sextupoles
(
MXT: 2-3-10-13
)
Dispersion
minimized in straights, no impact on chromaticity expectedf.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY
12
Straight section
sextupoles
show
no
effect
on
chromaticitySlide13
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY13
Spin coherence time studies: Required time
2 weeks
are requested to further explore ways to improve the SCT.
Make the lines of zero chromaticity coincide
Recent machine development studies provide the
slopes
for chromaticity
vs
MXL (not tried before
). A
negative MXL setting should pull the zero chromaticity lines toward each other
.Explore straight section
sextupoles
(no effect on chromaticity
)
Sensitivity of SCT seen before (but weaker
). Does
different degree of freedom help
?
A
dditional
information would be useful
:
Revisit RF-solenoid-induced
oscillations at low
field
Present analysis hampered by differential extraction on ridge target
.Explore contribution of emittance to SCT in white noise extraction Slide14
2. RF
Wien Filter f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY
14
P
recursor
EDM
concept
:
Use
RF Wien
filter to accumulate EDM signal
Insert RF-
dipole
into
ceramic
chamber
Slide15
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY15
RF
Wien
Filter: Field
calculations
Main
field
component
at
,
Main
field
component
at
,
Integral
compensation
of
Lorentz
force
at
Slide16
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY16
RF Wien Filter: First tests with beam
Commissioning:
Pulsed
mode
,
pulses
, each long,
BPM sensitivity at betatron sideband
frequency
used
to
adjust
and
to
match
Wien
filter
condition
,
Diagnosis
using COSY BCTCompensation achieved down to ~7 % beam
loss.
Beam
loss
(%)
Matching
of
phase
of
at
Beam
loss
(%)
E-B
phase
(
)
Requested 2 weeks of beam
time will be used
to fully commission
the RF Wien filter,
should do same job as RF solenoid. Matching
of
RF
field
to
RF
at
Slide17
Systematic study of machine imperfections using two straight section solenoids
Idea: The precise determination of the spin tune
can
be
exploited
to
map
out
the
imperfections
of
COSY.
f.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY
17
COSY
provides
two
solenoids in opposite straight sections:one of the
compensation solenoids
of
the
70 kV cooler:
,
The
main
solenoid
of
the
2 MV cooler:
.
Both
are
available dynamically in the cycle, i.e., their strength can be adjusted on flattop. Systematic
effects from machine imperfections
limit the achievable precision in a precuror experiment using an RF Wien filter. Slide18
Imperfection kick: Deuterons at MeV
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY18
The
requested
2
weeks
of
beam time
shall
be
used to
study
static
imperfections
with
artificial
spin
rotations
and
induced by two straight section solenoids. Ideal machine
with vanishing static imperfections: Saddle point at the origin
sea
level
at
Intrinsic
imperfection
kick
shifts saddle
point
away from
origin
Location of imperfection:
Slide19
Beam RequestWe request
in total 6 weeks of beam time for the activities:Spin coherence time studies (
contin
.
of #
176) (2 weeks),
RF
Wien
Filter
(2 weeks),Systematic study of machine imperfections using
two straight section solenoids (2 weeks),p
receeded by
1 MD week.
Investigations
difficult
,
require
time
consuming
machine
tuning
.
B
eam time
should
be scheduled as single block. f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY19Slide20
Backup slidesf.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY
20Slide21
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY21
Precursor
experiments
:
RF
methods
Use
existing
magnetic
machines
for
first
direct
EDM
measurements
Method
based
on
making
spin precession
in machine resonant with
orbit
motion
Two
ways
:
Use
an RF
device
that
operates
on
some
harmonics of the spin precession frequencyOperate ring on an imperfection
resonance Slide22
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY
22Precursor experiments: 1. Resonance
Method
with
„
magic
“ RF Wien
filter
Avoids coherent betatron oscillations of beam.
Radial RF-E and vertical RF-B
fields to
observe
spin
rotation
due
to
EDM.
Approach
pursued
for
a
first
direct
measurement at COSY.
„Magic RF Wien Filter“ no
Lorentz
force
Indirect
EDM
effect
Observable:
A
ccumulation
of
vertical
polarization
during
spin coherence timePolarimeter (dp elastic)stored dRF E(B)-field
In-plane polarization
Statistical
sensitivity
for
in the range
to
range
possible
.
Alignment
and
field
stability
of
ring
magnets
Imperfection
of
RF-E(B)
flipper
Slide23
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY
23Precursor experiments: 1. Resonance
Method
for
deuterons
at
COSY Parameters: beam energy
assumed EDM
E-
field
EDM effect accumulates in
Slide24
1. Resonance
Method Operation of „magic“ RF Wien filterf.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY
24
Radial E
and
vertical
B
fields
oscillate
, e.g.,
with
(
here
).
beam
energy
Spin coherence time may depend on excitation and on
harmonics
𝐾.Slide25
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY
25Parameters: beam energy
assumed
EDM
E-
field
EDM
effect
accumulates
in
Precursor
experiments
:
1.
Resonance
Method
for
deuterons
at
COSY
Linear
extrapolation
of
for
a time
period
of
yields
a
sizeable
.
Slide26
Development: RF E/B-Flipper (RF Wien Filter)f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY
26
Upgrade
test
flipper
with
electrostatic field plates ready end of year.Build lower power version using a stripline system
Build high-power version of stripline
system (
)
Work
by
S.
Mey, R
.
Gebel (Jülich)
J. Slim, D.
Hölscher
(
IHF RWTH Aachen)
Slide27
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY27
Precursor experiments:2. Resonant EDM measurement with
static
Wien F
ilter
Machine
operated
on imperfection spin resonance at
Similar
accumulation
of
EDM
signal
,
systematics
more
difficult
,
strength
of
imperfection
resonance
must
be
suppressed
by
closed
-orbit
corrections
.
Spin
rotation
in phase with orbit motionw
ithout static WFSlide28
1Make the lines of zero chromaticity coincide.
Recent machine development studies provide the slopes for chromaticity vs. MXL (not tried before).A negative MXL setting should pull the zero chromaticity lines toward each other.A “best case” chromaticity setup might work, as before.
ξ
X,Y
= 0
2
Explore straight section
sextupoles
(no effect on chromaticity)
Sensitivity of SCT seen before (but weaker).
Does different degree of freedom help?
Based on analysis now underway, additional information would be useful:
3
Revisit RF-solenoid-induced P
Y
oscillations at low field.
Present analysis hampered by differential extraction on ridge target.
4
Explore contribution of
emittance
in white noise extraction to SCT.
f.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY
28Slide29
Removing spin tune spread with sextupole fieldsObserve result in lifetime (SCT) of horizontal polarization
Major run in weeks 35 and 36 (August/September) 2013, lots of data
MXG
MXS
0
20
20
40
+
+
+
+
+
+
+
+
+
+
Best SCT points
for large horizontal
emittance
Best SCT
points
for
large
Δ
p/p
(longitudinal)
+
+
+
+
+
Units are in
percent
of power
supply
full scale.
Example of data
measured with the
time-marking
DAQ system
HORIZONTAL POLARIZATION
signs changed to
show linear effect
black = spin down
blue = spin up
Beam set up to
emphasize different
sources of
decoherence
,
which can be corrected
with
sextupole
fields.
Each
sextupole
field scan locates
one point on
2-D map.
Zero crossing
of inverse slope
locates
best SCT.
SCT
FIRST
2-D
MAP
Initial
Polarization
Slope
f.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY
29Slide30
MXG
MXS
0
20
20
40
+
+
+
+
+
+
+
+
+
+
Best SCT points
for large horizontal
emittance
Best SCT
points
for
large
Δ
p/p
(longitudinal)
+
+
+
+
+
Units are in percent
of power supply
full scale.
ξ
X
= 0
ξ
Y
= 0
Location of best SCT is closely
associated with location of
vanishing chromaticity.
Results comparable to calculated slopes
for best SCT (X, Y
emittance
, and
longitudinal
Δ
p/p)
and
zero chromaticity.
Slopes scaled to
percent units.
Offsets are
arbitrary.
Chromaticity effects are planar.
Sextupoles
adjust constant term.
COSY-Infinity calculations
by Marcel Rosenthal
best fit to
chromaticity
data
f.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY
30Slide31
Stability
5 days/nights of measurement
Measurements
using
cavity
(
method
2)
MXS @ 2%
shift
of
+0.3
expected
MXS @ 2%
shift
of
-0.22
expected
f.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY
31Slide32
Machine
HistorySuper Cycle:
1.
cycle
:
no
injection
,
dipole ramped to larger target momenta
for 4- 5 seconds2. cycle:
usual measurement
cycle
time
B-Field
of
bending
dipoles
measurement
Additíonal
dipole
ramp
Target
momenta
of
additional
ramp
:
1: 2028
MeV
/c
2: 2513
MeV
/c
3: 3097
MeV
/c
4: 3700
MeV
/c
5:
cycle
1
removed
(
default target momentum: 970 MeV/c)decreasingrestoringincreasingrestoringf.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY32Slide33
Charge
symmetric
No
EDM (
)
Do
particles
(e.g.,
electron
,
nucleon
)
have
an EDM?
f.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY
33
:
MDM
:
EDM
Physics
:
Fundamental
ParticlesSlide34
Physics
: SymmetriesParity:f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY
34
C-
parity
(
or
Charge
parity
):
Changes
sign
of
all
quantized
charges
electrical charge,
baryon number,
lepton number,
flavor charges,
Isospin
(3rd-component)
T-
S
ymmetry:
P
hysical laws are invariant under certain transformations Slide35
f.rathmann@fz-juelich.de
35Search for Permanent Electric Dipole Moments at COSY
Permanent EDMs
violate
P
and
T.
Assuming
CPT
to hold,
CP
violated also.
Not
Charge
symmetric
(
aligned
w
/
spin
)
EDMs:
Discrete
SymmetriesSlide36
J.M
.
Pendlebury
: „
nEDM
has
killed
more theories than any other single
expt.“
f.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY
36
Physics
:
Potential
of
EDMsSlide37
f.rathmann@fz-juelich.de
37Search for Permanent Electric Dipole Moments at COSY
For
transverse
electric
and
magnetic fields in a ring ( ),anomalous spin precession is
described by
Thomas-BMT equation:
Magic
condition
: Spin
along
momentum
vector
For
any
sign
of
, in a
combined electric
and
magnetic
machine
2.
For
(
protons
) in an all
electric
ring
x
(
magic
)
Principle
:
F
rozen
spin Method
Magic
rings
to
measure
EDMs
of
free
charge
particlesSlide38
2
beams simultaneously rotating in an all electric ring (cw, ccw
)
Status:
Approved
BNL-
Proposal
Submitted
to DOEInterest FNAL! Goal
for protons
f.rathmann@fz-juelich.de
38
Search for Permanent Electric Dipole Moments at COSY
Beat systematics:
BNL Proposal
CW
CCW
Polarization
EDM
Sokolov-Ternov
Gravitation
CW
CCW
Sokolov-Ternov
Gravitation
CW & CCW
beams
cancels systematic effects
Many
technological
challenges
need
to
be
metSlide39
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY39
srEDM
searches
:
Technogical
challenges
Charged
particle
EDM searches
require
development of a
new
class
of
high-
precision
machines
with
mainly
electric
fields for bending and focussing.Related topics:Electric field gradients
Spin
coherence
time
Continuous polarimetry
Beam
positioning
Spin
tracking
These
issues
must
be
addressed
experimentally
at
existing facilitiesSlide40
40
Search for Permanent Electric Dipole Moments at COSYf.rathmann@fz-juelich.de
Challenge:
Electric field for
m
agic rings
C
hallenge
to
produce
large
electric
field
gradients
R
field
only
Slide41
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY41
Challenge:
Niobium electrodes
Show
one
slide
on JLAB
data
HV
devices
DPP
stainless
steel
fine-grain
Nb
large-
grain
Nb
large-
grain
Nb
single-
crystal
Nb
Large-
grain
Nb
at
plate
s
eparation
of
a
few
cm
yields
~20 MV/mSlide42
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY42
Challenge:
Electric field for
m
agic rings
Electrostatic
separators
at
Tevatron
used
to
avoid
unwanted
interactions
-
electrodes
made
from
stainless steel Routine operation at spark/Year at MV/m
L~2.5 m
Need
to
develop
new
electrode
materials
and
surface
treatments
~
July
2013: Transfer of separator unit plus equipment from FNAL to JülichSlide43
A
one
particle with
magnetic moment
“spin tune”
“spin closed orbit vector”
ring
makes
one
turn
stable polarization
if ║
f.rathmann@fz-juelich.de
43
Search for Permanent Electric Dipole Moments at COSY
Challenge:
Spin
coherence
time
Spin
closed
orbitSlide44
Challenge: Spin coherence timef.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY44We usually
don‘t
worry
about
coherence of spins along
At
injection
all
spin
vectors
aligned
(
coherent
)
After
some
time,
spin
vectors
get
out
of
phase
and
fully
populate
the
cone
Polarization
not
affected
!
Situation very different, when you
deal with
machines with frozen
spin.
At
injection
all
spin
vectors
aligned
Later
,
spin
vectors
are
out
of
phase
in
the
horizontal plane
Longitudinal
polarization
vanishes
!
In an EDM machine with frozen spin, observation time is limited.Slide45
Challenge: SCT stimates (N.N. Nikolaev)
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY45One
source
of
spin
coherence are random variations of the spin tune due
to the momentum
spread in
the beam
and
is
randomized
by
e.g.,
electron
cooling
Estimate
:
Spin coherence time for deuterons may be 𝟏𝟎𝟎× larger than for protonsSlide46
EDM at COSY: COoler SYnchrotron
Cooler
and
storage
ring
for
(
polarized
)
protons
and
deuterons
Phase
space
cooled
internal
&
extracted
beams
Injector cyclotron
COSY
… the
spin-physics machine
for hadron physics
f.rathmann@fz-juelich.de
46
Search for Permanent Electric Dipole Moments at COSY
… an ideal
starting
point
for
a
srEDM
searchSlide47
New Idea: Ivan Koop‘s spin wheel
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY47
B
By
appropriate
choice
of
magnetic
field
,
the
spin
vector
rotates
fast
frequencies
of
the
order kHzJülich has expertise in SQUIDs, state-of-the art measurements allow for is (
This
would
revolutionize
the
way
we
conceive
EDM (
and
in
general
polarization
) experiments, because frequencies become directly measureable
. Slide48
How Ivan‘s spin wheel would
work?f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY48
F
requency
B
field
Find
the
value
of
B
where
spin
precession
frequency
disappearsSlide49
SQUIDs: Precision tools for accelerators
f.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY49Possible applications in accelerators, all of
which
are
needed
for
srEDM experimentsBeam current transformersBeam position monitorsBeam polarimetersBegin development with a measurement
of the noise spectrum
using three coils:Coil 35mm away
from center ANKE chamberCombined coils in same housing
GHz range
(one pickup loop)
MHz range
(several
hundered
loops)
Fluxgate sensor
kHz range
Measurement
of
noise
spectrum
at COSY in MD
week, July 2013Slide50
New Idea: Direct measurement of
electron EDMf.rathmann@fz-juelich.deSearch for Permanent Electric Dipole Moments at COSY50Bill Morse
(BNL EDM):
,
,
Nobody
knows
where
CPV is hiding, may well
be in the leptonic sector
Needs a dedicated R&D effort
Very attractive:
Tests all
ingredients
of
srEDM
experiments
with
Could
develop
into an independent long-term projectPolarimetry is an issueGoal:
Could
be
an
option
for
FNAL
using
the
electrostatic
Tevatron
separatorsSlide51
Step
Aim / Scientific goalDevice / Tool
Storage ring
1
Spin
coherence
time
studies
Horizontal RF-B
spin
flipper
COSY
Systematic
error
studies
Vertical
RF-B
spin
flipper
COSY
2
COSY upgrade
Orbit
control
,
magnets
,
…
COSY
First
direct
EDM
measurement
at
RF-E(B)
spin
flipper
Modified
COSY
3
Built
dedicated all-in-one ring for , ,
Common
magnetic-electrostatic deflectorsDedicated ring4
EDM
measurement of
, , at
Dedicated
ring
Step
Aim
/ Scientific
goal
Device / Tool
Storage ring
1
Spin
coherence
time
studies
Horizontal RF-B
spin
flipper
COSY
Systematic
error
studies
Vertical
RF-B
spin
flipper
COSY
2
COSY upgrade
Orbit
control
,
magnets
,
…
COSY
RF-E(B)
spin
flipper
Modified
COSY
3
Common
magnetic-electrostatic
deflectors
Dedicated
ring
4
Dedicated
ring
f.rathmann@fz-juelich.de
Search for Permanent Electric Dipole Moments at COSY
51
Timeline:
Stepwise
approach
all-in-
one
machine
for
JEDI
Time
scale
:
Steps
1
and
2:
years
(i.e., in POF 3)
Steps
3
and
4:
years
Slide52
Georg
Christoph Lichtenberg (1742-1799) “Man muß etwas Neues machen
, um
etwas
Neues
zu
sehen.”“You have to make (create) something new, if you want to see something new”f.rathmann@fz-juelich.de52
Search for Permanent Electric Dipole Moments at COSY