Brief Report

MTV-S1183 : Test of Time Reversal Symmetry

JiroJiro MurataMurata

y yusing polarized unstable Nuclei

Jiro Jiro MurataMurata

TRIUMF Science Forum 11/17/2010TRIUMF Science Forum 11/17/2010

Schedule 118:Schedule 118: Test Run Test Run 11/1PM 11/1PM –– 11/2 AM Done11/2 AM DonePhysics RunPhysics Run 11/25AM 11/25AM –– 11/30PM11/30PM Coming !Coming !

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+ Source Test Run 11/3 ~ now+ Source Test Run 11/3 ~ now

Schedule 118:Schedule 118: Test Run Test Run 11/1PM 11/1PM –– 11/2 AM11/2 AMPhysics RunPhysics Run 11/25AM 11/25AM –– 11/30PM11/30PM

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Beam Test Menu using 8Li Beam Test Menu using 8Li

UnpolUnpol 1Mpps @ 1Mpps @ pApA = 20uA= 20uA4Mpps4Mpps 30uA30uA

Asymmetry ~ 0.124Target Polarization ~ 41% 4Mpps4Mpps 30uA30uA

pol 0.7Mpps pol 0.7Mpps 30uA30uA2Mpps 2Mpps 40uA40uA

(17Mpps 80uA) ‘09(17Mpps 80uA) ‘09

Beam Polarization ~ 62%

Asymmetry Counters (Horizontal Only)Asymmetry Counters (Horizontal Only)

Simulate Maximum Radiation at Simulate Maximum Radiation at Production Run with Production Run with UnpolUnpol BeamBeam20Mpps 20Mpps expected, expected, 4Mpps4Mpps testedtested

Source Test : 3.7MBq 90Sr (max. 2.3MeV)Source Test : 3.7MBq 90Sr (max. 2.3MeV)

Test Beam Menu (cannot be performed with source)1. Polarized Beam Control2. Area Radiation (safety) Need Concrete Blocks (should be good for production run)

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3. High Rate Stability of Detectors (~Mpps in DC, ~10kHz/wire, Lvl-1 rate max. 80kHz)4. DAQ performance Confirmed ~20kHz bandwidth5. Beta Energy Difference (8Li max.13MeV)

Principle and Experimental SetupPrinciple and Experimental Setup

Measuring Mott Scattering using Drift ChamberMeasuring Mott Scattering using Drift Chamber

Backward Backward scattscatt. . ~ 10^~ 10^-- 44

Figure of MeritFigure of Meritmax. at 110deg.max. at 110deg.

Analyzing PowerAnalyzing Power~ 50% max.~ 50% max.

KAWAMURA-SEITAIBASHI ‘08-‘09

Transverse Polarized 8Li ~10Transverse Polarized 8Li ~107 7 pps pps –– 80% pol. @ 30keV80% pol. @ 30keVStopper: Stopper: Aluminium Aluminium at room temperature, B0=500Gat room temperature, B0=500G

44

pppp p ,p ,

LevelLevel--1 Trigger : Plastic Logic1 Trigger : Plastic LogicLevelLevel--2 Trigger : DC hit number selection2 Trigger : DC hit number selection TOYODA ‘08, SEITAIBASHI ‘09,

NAKAYA ‘10

Modulated Polarized Beam Control Modulated Polarized Beam Control

16s/32s16s/32s

8Li on Stopper : 700kpps @ pA=30uA

55Periodic Periodic （（Last Year, 30sLast Year, 30s）） NonNon--Periodic : Systematics ReductionPeriodic : Systematics Reduction

Beam Polarization, angleBeam Polarization, angle

Asymmetry ~ 0.10Target Polarization ~ 33%g

16s/32s16s/32sAsymmetry Counters (Horizontal Only)Asymmetry Counters (Horizontal Only)

Stopper : 10um Al @ 500G, T1~2.3secB P l i ti 50% b tt t b i dIKEDA ‘10

66Forward Polarimeter (FPOL)Forward Polarimeter (FPOL)

Beam Polarization ~ 50% better to be improved

Beam Polarization Angle Precision ~0.4deg. (very preliminary)(Crucial at Precision at Final State Interaction)

IKEDA 10

Dominant Systematics : NDominant Systematics : N--correlationcorrelation

77Precision Measurement of beam polarization direction is crucial Precision Measurement of beam polarization direction is crucial

New FastNew Fast--DAQ with buffering TDC readout (~20kHz): How to read chargeDAQ with buffering TDC readout (~20kHz): How to read chargeqtc0

Entries 507240Mean 2327RMS 251.3

1600 1800 2000 2200 2400 2600 28000

100

200

300

400

500

600

700

800

900

qtc0Entries 507240Mean 2327RMS 251.3

qtc ch0

Plastic pQTC from 8Liqtc0

Entries 507240Mean 2327RMS 251.3

1600 1800 2000 2200 2400 2600 28000

100

200

300

400

500

600

700

800

900

qtc0Entries 507240Mean 2327RMS 251.3

qtc ch0

Integration Discharge

qtc0Entries 507240Mean 2327RMS 251.3

1600 1800 2000 2200 2400 2600 28000

100

200

300

400

500

600

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qtc0Entries 507240Mean 2327RMS 251.3

qtc ch0

ONISHI ‘10

Time Width

ASD (A Sh Di i) hi

Use Time-width LVDS discri-outas “charge” information

Time Width

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QTC (Charge to Time Conv.)3ch/chip for T2KQTM NIM module $4k/6ch x 208ch = $140k

ASD (Amp-Shaper-Discri) chip. 4ch/chip for ATLAS-TGC$1.7k/64ch x 208ch = $5.5k

gProportional to log(Q)pQTC (pseudo-QTC)

TOTSUKA ‘10

Detector Test using 8Li Beam : Rate StabilityDetector Test using 8Li Beam : Rate Stability

50% Ar + 50%CO2 @ -2.7kVTrigger – DC timing

Small drift Velocity Reduction,Large BG level

1Mpps @ pA = 20uA [unpol]

4Mpps @ pA = 30uA [unpol]g

DC charge (TDC width)

Gain Reduction Space Charge Effect max. ~10Mpps expected at production run~ low efficiency issue

99TDC [ch] (1000ch = 100ns)

Detector Test using 8Li Beam : Bias Effect (how to compete with Space Charge Eff.)Detector Test using 8Li Beam : Bias Effect (how to compete with Space Charge Eff.)

700kpps @ pA = 30uA [pol]Trigger – DC timing

positive dv/dE

100%CO2 @ -3.4kV

V~15cm/uspositive dv/dE

100%CO2 @ -3.1kV

DC charge (TDC width)KNOLLKNOLL

CH4 (P10) : negative dv/dE (also bad for wire aging)CO2 : very large v positive dv/dE

Gain increased

1010

CO2 : very large v, positive dv/dE

Applying HV seems effective against Space Charge Effect,Applying HV seems effective against Space Charge Effect,iif we do not use CH4f we do not use CH4

TDC [ch] (1000ch = 100ns)

Comparing 8Li Beam and 90Sr sourceComparing 8Li Beam and 90Sr sourceTrigger – DC timing Trigger – DC timing

dE/dX~1.2MeV/cm2/g @ 0.7MeV, 4.3MeV

(Sca

led)

8Li @ 700kpps 90Sr @ 3 7MBq

8Li @ 4Mpps

Cou

nt

90Sr @ 3.7MBq@ pp 90Sr @ 3.7MBq

Pileup/Accidental contribution increased for 8Li

DC charge (TDC width) DC charge (TDC width)

Small charge events ~ Small charge events ~ BremsstralungBremsstralung ??Cut may be effectiveCut may be effective

1111

20% Ar + 80% CO2, -3kV 50% Ar + 50% CO2, -2.7kVTDC [ch] (1000ch = 100ns) TDC [ch] (1000ch = 100ns)

Detector Test using 8Li Beam Detector Test using 8Li Beam 8Li @ 700kpps 8Li @ 4Mpps

Real Signal

Relatively, many XRelatively, many X--rays are generated by high energy electrons from 8Lirays are generated by high energy electrons from 8Li

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XX--rays signals generates small charge pulsesrays signals generates small charge pulses

Can be removed by “small chargeCan be removed by “small charge--cut”cut”LEOLEO

Gas Study using 90Sr after test runGas Study using 90Sr after test run

Unquenched UV’s

50% Ar + 50% CO2 @ -3 3kV 80% Ar + 20% CO2 @ -2 7kV50% Ar + 50% CO2 @ -3.3kV ~8cm/us

80% Ar + 20% CO2 @ -2.7kV

Insufficient UV Quenching by CO2Insufficient UV Quenching by CO2

Excellent Pulse Shape Obtained for CF4Excellent Pulse Shape Obtained for CF4

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100% CF4 @ -3.0kV ~10cm/1us

Excellent Pulse Shape Obtained for CF4Excellent Pulse Shape Obtained for CF4Strong quenching, Fast RisingStrong quenching, Fast Rising

Timing Properties of various Gas mixturesTiming Properties of various Gas mixtures

Trigger – DC timing

(Sca

led)

gg g

Drift Velocity Reduction

Cou

nt

drift timedelayed after-pulse

Fast : reduction of accidentalFast : reduction of accidental

CO2: Very fast drift velocityCO2: Very fast drift velocity very slow delayed pulsevery slow delayed pulse

CF4: fast drift velocity, very fast delayed pulseCF4: fast drift velocity, very fast delayed pulseFast : reduction of accidentalFast : reduction of accidentalHigh EfficiencyHigh Efficiency

Broad : weak to accidentalBroad : weak to accidental

TDC [ h] (1000 h 100 )

CO2: Very fast drift velocity, CO2: Very fast drift velocity, very slow delayed pulsevery slow delayed pulse Low EfficiencyLow Efficiency

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TDC [ch] (1000ch = 100ns)

Indeed, LvlIndeed, Lvl--2 trigger at the test run was poor 2 trigger at the test run was poor

)

DC charge (TDC width)

Gain Properties of various Gas mixturesGain Properties of various Gas mixtures

nt (S

cale

dC

ou

TDC [ch] (1000ch = 100ns)

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CO2: many smallCO2: many small--charge pulses (UV ?, sensitive to X??)charge pulses (UV ?, sensitive to X??)

ArAr/CF4: No small pulses at all/CF4: No small pulses at all

Understanding CO2 behavior Understanding CO2 behavior

100% CO2 50% Ar + 50% CF4Small pulses

100% CO2 50% Ar + 50% CF4No small pulses without CO2No small pulses without CO2

Conclusion: CO2 is not suitable for our experiment although it has excellent drift velocity.Conclusion: CO2 is not suitable for our experiment although it has excellent drift velocity.CF4 seems perfect (cost: $15/day @ 30cpm)CF4 seems perfect (cost: $15/day @ 30cpm)

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CF4 seems perfect, (cost: $15/day @ 30cpm)CF4 seems perfect, (cost: $15/day @ 30cpm)

Fake hits from small pulsesFake hits from small pulses 80% Ar + 20% CO2, -2.9kV

Without charge-cut With charge-cut

SSmall pulses seems to make fake hits (UV from other cell, X from somewhere)mall pulses seems to make fake hits (UV from other cell, X from somewhere)

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SSmall pulses seems to make fake hits (UV from other cell, X from somewhere)mall pulses seems to make fake hits (UV from other cell, X from somewhere)

ArAr/CF4 is the best/CF4 is the best

Drift Time Gain

CF4: High Gain / CF4: High Gain / Small CurrentSmall Current

CF4: FastCF4: Fast

CF4: High EfficiencyCF4: High Efficiency

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Source Test using Source Test using ArAr/CF4/CF4Asymmetry ~ 0.124Target Polarization ~ 41%Beam Polarization ~ 62%

Asymmetry Counters (Horizontal Only)Asymmetry Counters (Horizontal Only)

1919LvlLvl--2 Rate ~ 3.3kHz from 3.7MBq (~102 Rate ~ 3.3kHz from 3.7MBq (~10--33) ) Double Track Purity ~ 40% (5% at RunDouble Track Purity ~ 40% (5% at Run--I)I)

New Clustering tool is under developmentNew Clustering tool is under development1. Remove fake hits from pattern recognition1. Remove fake hits from pattern recognition2. Fast tracking to reduce CPU time2. Fast tracking to reduce CPU time

Detector Test using 8Li Beam Detector Test using 8Li Beam

8Li/90Sr correction

8Li Lvl-2/Lvl-1 0.04890Sr 0.21

Lvl-2 purity decreased to ~ 25% of 90Sr

90Sr Lvl-2 rate : 3.3kHz @ 3.7MBq with best gas conditionD bl T k t it 40% ( b 2) W-rate 1.3kHz @ 90Sr 3.7MBqDouble Track event purity ~40% (can be x2) W rate 1.3kHz @ 90Sr 3.7MBq

W-rate 0.33kHz @ 8Li 3.7MBq Same rate as source

Expected rate inW-rate 1kHz @ 8Li 15Mpps (1.5x107pps)

T t l W 600M t

Expected rate in production run

Expected Statistics

2020

Total W = 600MeventsR precision = 0.12%

Expected Statisticsand Physics precision

Results from MTV RunResults from MTV Run--I Nov. 2009I Nov. 2009

Beam Polarization 8% Beam Polarization 8% --> 80%> 80%Effective Analyzing Power 6.5% Effective Analyzing Power 6.5% --> 11%> 11%

Preliminary Preliminary 3.6% stat. precision 3.6% stat. precision from 70% datafrom 70% data3% 3% expected for full data analysisexpected for full data analysis

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Detector Test using 8Li Beam Detector Test using 8Li Beam

TDC [ h] (1000 h 100 )

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TDC [ch] (1000ch = 100ns)R precision = 0.12%