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Storage Ring EDM Technical Review – 12/7/2009. Polarimeter Development. Hello. STORAGE RING POLARIMETRY. Edward J. Stephenson, IUCF. 0. Storage Ring EDM Technical Review – 12/7/2009. Polarimeter Development. Requirements. - PowerPoint PPT Presentation
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Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 0
Polarimeter Development
Hello
STORAGE RINGPOLARIMETRY
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 1
Polarimeter Development
Requirements
1. Measure a change in the vertical polarization with a sensitivity of 10−6. Provide a continuous record with time. Reduce systematic errors to below the sensitivity limit.
2. Track the magnitude of the polarization with time.
3. Provide transverse (X) asymmetry data continuously for control. Operate at high efficiency.
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 1
Polarimeter Development
Requirements
1. Measure a change in the vertical polarization with a sensitivity of 10−6. Provide a continuous record with time. Reduce systematic errors to below the sensitivity limit.
2. Track the magnitude of the polarization with time.
3. Provide transverse (X) asymmetry data continuously for control. Operate at high efficiency.
Development proposal made to COSY-Jülich in 2007.Ring design was for 1 GeV/c deuteron beam (250 MeV)
Best scheme requires deuteron scattering from carbon.
Conduct study using as much existing equipment as possible.
(Begin studies of production/preservation of horizontal polarization.)
Deuteron and proton polarimeters are similar.
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 2
Polarimeter Development
Analyzing Reaction Characteristics
d+C elastic, 270 MeV
available at COSY
desired range
FOM = σA2
Y.
Sa
tou
, P
L B
54
9,
30
7 (
20
02
)
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 2
Polarimeter Development
Analyzing Reaction Characteristics
d+C elastic, 270 MeV
available at COSY
desired range
FOM = σA2
inelastic scattering
(d,p) reactions + breakup
Inelastic and(d,p) reactions
follow trendof elastic. Sokeep them!
Y.
Sa
tou
, P
L B
54
9,
30
7 (
20
02
)
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 2
Polarimeter Development
Analyzing Reaction Characteristics
d+C elastic, 270 MeV
available at COSY
desired range
FOM = σA2
inelastic scattering
(d,p) reactions + breakup
Inelastic and(d,p) reactions
follow trendof elastic. Sokeep them!
DAQ does not keep just single channel.Include low Q-value reactions.
(Tensorcan be
large anduseful.)
Y.
Sa
tou
, P
L B
54
9,
30
7 (
20
02
)
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 3
Polarimeter Development
Polarimeter Properties
Broad acceptance for high efficiency:
Angle range = 5° to ~20°Excitation range < ~40 MeVNo particle identificationStable properties rely on stable gains, thresholds, etc.Build and calibrate (including systematic errors properties)
Implications for polarimeter design:
Low analyzing power particles can be removed with an absorberCount everything above thresholdDAQ can be simple (scaler) and fast for high statistics, low dead timeDetector must be insensitive to rate changesThick targets are required (several cm) for high efficiency (~1%)
Design features that go beyond current polarimeters:
Extraction from a storage ring onto a thick internal targetReduction of systematic error effects to 10−6
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 4
Polarimeter Development
COSY ring:
Use EDDAdetector
COSY tests
EDDA detector:
Rings and bars to determine angles.
Tube target,extracts alonginside edge.
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 4
Polarimeter Development
COSY ring:
Use EDDAdetector
COSY tests
EDDA detector:
Rings and bars to determine angles.
FRONT: This iswhere EDDA lookslike an EDM polarimeter.
REAR: This is acheck of methods
Run at 0.97 GeV/c.
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 4
Polarimeter Development
COSY ring:
Use EDDAdetector
COSY tests
EDDA detector:
Rings and bars to determine angles.
LEFT
UP
DOWN RIGHT
Azimuthal angles yield two asymmetries:
RL
RLEDM
UD
UDg
2
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 5
Polarimeter Development
Target Concept
Target solution found at COSY:
15 mm
White noiseapplied to
electric fieldplates.
beam core
expanded vertical phase space
endview
maximumallowed at
COSY
Do enough particles penetrate far enough into the frontface to travel most of the way through the target?
This requires a comparison of the efficiency with model values.
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 6
Polarimeter Development
Rocker test:
Target Vertical Angle and Efficiency Test
How sensitive to vertical angle?
+
−
Best alignment with target front edge.
FRONT
BACK
× 10−3
Efficiency is the sum ofevents into the down andup segments of thedetector divided by theparticles lost from the beam.
Measurements arehigher than Monte Carlo predictions basedon model of EDDAdetector and deuteron-carbon reactions,including elastic,inelastic and transfer.
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 6
Polarimeter Development
Rocker test:
Target Vertical Angle and Efficiency Test
How sensitive to vertical angle?
+
−
Best alignment with target front edge.
FRONT
BACK
Measurements arehigher than Monte Carlo predictions basedon model of EDDAdetector and deuteron-carbon reactions,including elastic,inelastic and transfer.
Slope corresponds totypical depth in targetof 0.2 mm, larger thanthe multiple scatteringwidth of σ = 0.013 mmafter 15 mm of carbon.
depth
Efficiency is the sum ofevents into the down andup segments of thedetector divided by theparticles lost from the beam.
× 10−3
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 6
Polarimeter Development
Rocker test:
Target Vertical Angle and Efficiency Test
How sensitive to vertical angle?
+
−
Best alignment with target front edge.
FRONT
BACK
Measurements arehigher than Monte Carlo predictions basedon model of EDDAdetector and deuteron-carbon reactions,including elastic,inelastic and transfer.
Slope corresponds totypical depth in targetof 0.2 mm, larger thanthe multiple scatteringwidth of σ = 0.013 mmafter 15 mm of carbon.
depth
Efficiency is the sum ofevents into the down andup segments of thedetector divided by theparticles lost from the beam.
× 10−3
Efficiencies are low (×10) because ofthinner target and larger minimum angle.
Success.
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 7
Polarimeter Development
Systematic Error Effects
Goal: keep errors in change of asymmetry to less than 10−6.
Things can change:geometryrate
Use standard tricks
↑ + ↓ L + R )()(
)()(
1
1 2
RL
RLr
r
rpA
(good to first order in the errors)
Correct effects arising at higher order
Try to use detector information: correction parameters
Geometry:)()(
)()(
1
1 2
RR
LLs
s
s
Rate: RL (instantaneous rate)
This requires a calibration of sensitivity to systematic errors.
Will this work?
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 8
Polarimeter Development
Tests made at the KVI (2007)
130 MeVpolarized deuterons
18°
carbonribbontarget
Phoswichscintillationdetectors
The cross ratio fails at second order in the errors.
222
22
2223
2 )1(11
21
1(exp) x
x
A
x
A
Aux
x
A
Au
u = p(+) – p(−), p(−) < 0
Calculation based ondeuteron elasticscattering data at130 MeV and measuredbeam polarizations.
“true” asymmetry
observed asymmetry
Measure effects using errors >100 bigger than expected.
(Note: Asymmetry will also be larger.)
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 9
Polarimeter Development
COSY results
Scan: position −2 to 2 mm angle −5 to 5 mradRate varies during store
Make a linear fit tothe data from thestores. Assume thezero rate point isindependent of rateand can be usedfor the analysis ofgeometry effects.
Use the slope forthe study of rateeffects (pileup).
1 Rate and geometry effects are separable.
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 10
Polarimeter Development
COSY results
2
X points
Angle points
10%
Corrections for X and θ match.One index can be used for both.
0.1%
For the cross ratio, second ordereffects are smaller.
Analyzing power Ay = 0.35 (front).
Correction Parameter
Correction Parameter
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 11
Polarimeter Development
COSY results
Tests were made with the beam shifting by 4 mm during the store.
uncorrected
corrected forrate and geometry
V+ polarization case
slope: −1.4 ± 28 × 10−6 /s
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 11
Polarimeter Development
COSY results
Tests were made with highrate and displaced beam.
uncorrected
corrected forrate and geometry
T− polarization,2 mm displaced
slope: −4 ± 11 × 10−6 /s
corrected for rate
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 11
Polarimeter Development
COSY results
3
Tests were made with highrate and displaced beam.
uncorrected
corrected forrate and geometry
T− polarization,2 mm displaced
slope: −4 ± 11 × 10−6 /s
Corrections work.
For deuteron EDM ring: position changes < 10 μm initial vertical ε < 0.01gives control of systematicsto < 30 ppb, well underrequirement.
Scaling down:
cross ratio:A’/A = 0.0055ε = 0.01Δp = 0.05use (A’/A)ε2Δp
Since asymmetry depends only on count rates andcalibration coefficients, we get results in real time.
corrected for rate
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 12
Polarimeter Development
μ-solenoid test
add 60-turn solenoidto ring running 100A
EDDA
polarity knownonly to COSY
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 12
Polarimeter Development
μ-solenoid test
add 60-turn solenoidto ring running 100A
EDDA
polarity knownonly to COSY
data sample from rear detector
Solenoid: ON OFF
Data correction forrate brings averageonto straight line.
data excludedwhile magnet ramps
Prediction: 0.87 mradMeasured: 1.4 ± 0.4 mrad
Polarityagrees!
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 13
Polarimeter Development
Protons
Near 230 MeVthe forwardcross sectionand analyzingpower arefavorable.
proton + carbon elastic scattering
We can expect:efficiency ~ 1.1 % (over 2π)analyzing power ~ 0.6
with some selection on elastics
HO Meyer, PRC 27, 459 (1983)
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 14
Polarimeter Development
Polarimeter
Location of polarimeter in (half of) storage ring straight section
beam
Polarimeter:Note that thedetectors forthe counter-rotating beamshare the targetat the center ofthe quadrupole.
Injection system
RF solenoid used to precesspolarization of opposite bunchesinto the ring plane.
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 15
Polarimeter Development
Polarimeter
(Half) Polarimeter in the ring:
cm
One target isshown. Wewant a targetavailable fromat least theleft, right, upand downdirections.
Quadrupoles hereare larger aperturefor clearance.
5° to 20°acceptance
Generic detector: (?) Multi-resistive plate chamber (?) Micro-megas (?) Gas electron multiplier (?) …other
Absorber to removelow analyzing powerparticles. (Detectorchoice can also givediscrimination.)
Equal rate readout pads
Rate = 800 /s/pad
In one store: 4105.1
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 15
Polarimeter Development
Polarimeter
(Half) Polarimeter in the ring:
cm
One target isshown. Wewant a targetavailable fromat least theleft, right, upand downdirections.
Quadrupoles hereare larger aperturefor clearance.
5° to 20°acceptance
Generic detector: (?) Multi-resistive plate chamber (?) Micro-megas (?) Gas electron multiplier (?) …other
Absorber to removelow analyzing powerparticles. (Detectorchoice can also givediscrimination.)
Equal rate readout pads
Rate = 800 /s/pad
In one store: 4105.1
MRPC prototypeMRPC prototype
GrazianoGraziano
MRPCFrascati, U. Rome
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 15
Polarimeter Development
Polarimeter
(Half) Polarimeter in the ring:
cm
One target isshown. Wewant a targetavailable fromat least theleft, right, upand downdirections.
Quadrupoles hereare larger aperturefor clearance.
5° to 20°acceptance
Generic detector: (?) Multi-resistive plate chamber (?) Micro-megas (?) Gas electron multiplier (?) …other
Absorber to removelow analyzing powerparticles. (Detectorchoice can also givediscrimination.)
Equal rate readout pads
Rate = 800 /s/pad
In one store: 4105.1
Micro-MegasINP Demokritos, Saclay, BNL
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 16
Polarimeter Development
R & D 3-year Plan
Year 1: Simulation and design of proton polarimeterDatabase creation (cross section and analyzing power)Monte Carlo simulationEngineering design (including electronics)
Detector selectionPrototype tests (COSY, KVI, IUCF…)Inclusion in Monte Carlo simulation
Year 2: ConstructionParts procurement, machine shop, assembly
Installation (at COSY)
Year 3: Commissioning and calibrationDesign verificationOperating point determinationMeasurement of systematic error sensitivity
Goals (milestones) Produce a working EDM polarimeter for the ring
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 17
Polarimeter Development
Resources needed:
R & D 3-year Plan
Note: This is an opportunity for separate funding throughIndiana University or other EDM Storage Ring institutions.
Costs (k$) withIU overhead
Personnel post-doc 300student 140
Travel 140
Construction design 60fabrication 160
Other (add ~1/4) 200
TOTAL 1,000
Storage Ring EDMTechnical Review – 12/7/2009
Edward J. Stephenson, IUCF 18
Polarimeter Development
Polarimeter Development Team: (participating at COSY)
Indiana: Ed Stephenson*, Astrid Imig (BNL)
KVI-Groningen: Gerco Onderwater*, Marlène da Silva e Silva, Klaas Brantjes, Duurt van der Hoek, Wilburt Kruithoff, Oscar Versolato
COSY Jülich: Ralf Gebel, Andreas Lehrach, Bernd Lorentz, Dieter Prasuhn, Hans Stockhorst
BNL: Vasily Dzordzhadze, Don Lazarus, Bill Morse, Yannis Semertzidis
Frascati: Paolo Levi Sandri, Graziano Venanzoni
U. of Rome: Francesco Gonnella, Roberto Messi, Dario Moricciani
Thanks to: Olaf Felden (COSY), Frank Hinterberger (Bonn), Rudolf Maier (COSY), Hans Ströher (COSY), Univ. Münster
Regis U.: Fred Gray
* Spokespersons for polarimeter development
EDM Polarimeter Team