alain blondel, mice collab. ral 8-10 july 2002 systematics 1 experimental systematics outline...

Alain Blondel, MICE collab. meting @ RAL 8-10 July 2002

Systematics 1

Experimental Systematics Experimental Systematics

OUTLINEOUTLINE

• starting from Janot’s work, will try to initiate a reflexion on starting from Janot’s work, will try to initiate a reflexion on systematic errors.systematic errors.

. MICE measures e.g. (. MICE measures e.g. (outout inin))exp exp = 0.904 = 0.904 ± 0.001 (statistical)± 0.001 (statistical)

and compares with (and compares with (outout inin))theory. theory. = 0.895 = 0.895

and tries to understand the difference. SIMULATIONSIMULATION

REALITYREALITY

MEASUREMENTMEASUREMENT

theory systematics: modeling of cooling cell is not as reality

experimental systematics:modeling of spectrometers is not as reality


Systematics 2

DWARF4.0 DWARF4.0 What’s in it?What’s in it? Particle transport in magnetic field and in RF; homogeneous field.Particle transport in magnetic field and in RF; homogeneous field.

Multiple Scattering in matter;Multiple Scattering in matter;

tracker: 4 sets of three layers of 500 micron scintillating fibers tracker: 4 sets of three layers of 500 micron scintillating fibers Energy Loss (average and Landau fluctuations) in matter;Energy Loss (average and Landau fluctuations) in matter; Bremsstrahlung in matter; no showering Bremsstrahlung in matter; no showering

Beam contamination with pions, pion decay in flight;Beam contamination with pions, pion decay in flight; Muon decay in flight (with any polarization), electron transport;Muon decay in flight (with any polarization), electron transport;

Poor-Man Cooling Simulation (only BPoor-Man Cooling Simulation (only Bzz and E and EZZ) to quantify) to quantify particle and correlation losses with cooling;particle and correlation losses with cooling;

Gaussian errors on measured quantities (x, y, t).Gaussian errors on measured quantities (x, y, t).


Systematics 3

DWARF4.0: DWARF4.0: What’s not in ?What’s not in ? Imperfections of magnetic fields; heating at solenoid exits;Imperfections of magnetic fields; heating at solenoid exits; (A field map and step tracking will be needed here… (A field map and step tracking will be needed here… Might be the source of important bias and systematic uncertaintyMight be the source of important bias and systematic uncertainty

Dead channels; Dead channels; Misalignment of detector elements;Misalignment of detector elements; Background of any origin (RF, beam, …)Background of any origin (RF, beam, …) (Could well spoil the measurement. Need redundancy in case…)(Could well spoil the measurement. Need redundancy in case…)

track fit in presence of noise and dead channels (pattern recognition)track fit in presence of noise and dead channels (pattern recognition) electron ID detector electron ID detector (definitely needs a geant4 type simulation for showers) (definitely needs a geant4 type simulation for showers)

Fortran 77 + PAWFortran 77 + PAW


Systematics 4

Step III: TWO spectrometers

At this step we:-- Turn on and map the second solenoid -- Debug Spectrometer # 2-- Measure inout and the ratio-- Field reversal is important for E ^ B effects

THIS IS A VERY IMPORTANT STEP : THESE RESULTS WILL BE PART OF THE FINAL ONES

(Systematics on inout )

+ +

and --


Systematics 5

tracking detectors simulatedtracking detectors simulated


Systematics 6

Emittance Reduction:Emittance Reduction: Results Results R = R = outout/ / inin

GeneratedGenerated

MeasuredMeasured

RRGEN,GEN, 1. 1.

RRMEAS,MEAS, (1.+ (1.+))22

Note: Note: is purely instrumental is purely instrumental(mostly due to multiple scatt.(mostly due to multiple scatt. in the detectors). It can bein the detectors). It can be predicted and corrected for, predicted and corrected for, if not too large. if not too large.

A 0.9% measurement A 0.9% measurement with 1000 single with 1000 single ’s’s

(corresponding to(corresponding to• 25,00025,000 single single’s produced’s produced• 70,00070,000 “20 ns bunches” sent “20 ns bunches” sent

Each entry is the ratio ofEach entry is the ratio ofemittances (out/in) fromemittances (out/in) from

a sample of 1000 muons. a sample of 1000 muons. Biases and resolutions are Biases and resolutions are determined from this kind determined from this kind of plots in the following. of plots in the following.

(No cooling)(No cooling)

Bias Bias 1% 1%

(No cooling)(No cooling)


Systematics 7

Resolution, bias, systematicsResolution, bias, systematics

The emittance is obtained from the second moments of the 6D distribution (width)

The width of measured distribution is the result of the convolution ofThe width of measured distribution is the result of the convolution of the true width with the measurement resolution the true width with the measurement resolution

xxmeasmeas))2 2 = = xx

truetrue))2 + 2 + xxdetdet))22

The detector resolution generates a BIAS on the evaluation of the width The detector resolution generates a BIAS on the evaluation of the width of theof thetrue distribution. This bias must be corrected for. true distribution. This bias must be corrected for.

xxmeas meas == xx

true true ( 1 + ½ ( 1 + ½ xxdetdet))22/ / xx

truetrue))2 2 ) )

For the bias to be less than 1%, the detector resolution must be (much)better than 1/7 of the width of the distribution to be measured, i.e. the beam size at equilibrium emittance. Say 1/10.

The systematic errors result from uncertainties in the bias corrections.Rule of experience says that the biases can be corrected with a typical precision of 10% of their value (must be demonstrated in each case).


Systematics 8

Equilibrium emittance: 3000 mm.mrad = 75 mm X 40 mradEquilibrium emittance: 3000 mm.mrad = 75 mm X 40 mrad

1. Spatial resolution must be better than 10 mm 1. Spatial resolution must be better than 10 mm VERY EASY, VERY EASY, The resolution with a 500 micron fiber is 500/The resolution with a 500 micron fiber is 500/12 =144 12 =144 mm

2.2. Angular resolution must be better than 6 mrad…Angular resolution must be better than 6 mrad…

22x’ x’ = ( = ( 22

x1 x1 + + 22x1 x1 )/D + ()/D + (x’ (m.s.) x’ (m.s.) ))22

( ( 22x1 x1 + + 22

x1 x1 )/D < 1mrad for D = 30 cm. )/D < 1mrad for D = 30 cm.

x’ (m.s.) x’ (m.s.) = 13.6/ = 13.6/ P P x/X° x/X° x = detector thickness X° = rad. Length of materialx = detector thickness X° = rad. Length of material x = 1.5 mm of scintillating fiber (3 layers of 500 microns) X° = 40 cm x = 1.5 mm of scintillating fiber (3 layers of 500 microns) X° = 40 cm => => x’ (m.s.) x’ (m.s.) = 6 mrad…. = 6 mrad….

JUST MAKE IT! Bias is due to M.S. in the last planes of tracking detectors. Less MS is clearly desirable….

Requirements on detectorsRequirements on detectors


Systematics 9

Requirements on detectors (ctd)Requirements on detectors (ctd)

3. Time resolution 3. Time resolution

Must be better than 1/7 of the rms width of the particles contained Must be better than 1/7 of the rms width of the particles contained in the RF bucket. in the RF bucket.

200 MHz => 5 ns period, 2.5 ns ½ period, rms = 700 ps approx. 200 MHz => 5 ns period, 2.5 ns ½ period, rms = 700 ps approx. Need 70 ps or better. Need 70 ps or better.

Fast timing with scintillators gives 50 ps (with work) OK. Fast timing with scintillators gives 50 ps (with work) OK.

(This also provides pi/mu separation of incoming particles) (This also provides pi/mu separation of incoming particles)

4. t’ = E/Pz resolution. Trickier, needs reconstruction. * ->4. t’ = E/Pz resolution. Trickier, needs reconstruction. * ->

OK OK


Systematics 10

Tracker performance Tracker performance Resolution on pResolution on pTT::• Same for all particles;Same for all particles; (4 plates) (4 plates)• (p(pTT) ) 0.8 MeV/c. 0.8 MeV/c.

Resolution on pResolution on pZZ::• Strong dependence on pStrong dependence on pTT;; • Varies from 1 to 50 MeV/c.Varies from 1 to 50 MeV/c.

20%20%

10,000 muons10,000 muons10,000 muons10,000 muons


Systematics 11

Emittance MeasurementEmittance MeasurementTransverse variable ResolutionTransverse variable Resolution

( ( p pTT/p/pZZ) ) (p(pTT/p/pZZ) ) 2.5% 2.5%

Longitudinal variable ResolutionLongitudinal variable Resolution( ( E/p E/pZZ) )

(E/p(E/pZZ) ) 0.25% 0.25%


Systematics 12

In order to keep experimental systematics at the level of statistical errors, In order to keep experimental systematics at the level of statistical errors, MICE must getMICE must get

syst.syst.((outout inin))exp exp < 10 < 10 –3–3

This will be a sum of possible effects This will be a sum of possible effects (non exhaustive list…. do you see more?)(non exhaustive list…. do you see more?)

-- magnetic field knowledge (will scale emittance prop to -- magnetic field knowledge (will scale emittance prop to B/B)B/B) need statement on magentic field measurementsneed statement on magentic field measurements--- uncertainty on MS in last tracker planes - uncertainty on MS in last tracker planes and in space between tracker and cooling cell and in space between tracker and cooling cell need thought and statement. need thought and statement.

-- fake points or fake tracks due to noise/inefficiencies,-- fake points or fake tracks due to noise/inefficiencies, field inhomogeneities, etc.. field inhomogeneities, etc.. need simulation !!need simulation !!

each of which should be << 10-3 .


Systematics 13

Tracking devicesTracking devices

T.O.F. IIIT.O.F. IIIPrecise timingPrecise timing

Electron IDElectron IDEliminate muons that decay Eliminate muons that decay

Tracking devices: Tracking devices: Measurement of momentum angles and positionMeasurement of momentum angles and position

T.O.F. I & IIT.O.F. I & II

Pion /muon ID and precise timingPion /muon ID and precise timing


Systematics 14

Emittance measurementEmittance measurement

Each spectrometer measures 6 parameters per particle Each spectrometer measures 6 parameters per particle x y t x y t x’ = dx/dz = Px’ = dx/dz = Pxx/P/Pz z y’ = dy/dz = P y’ = dy/dz = Pyy/P/Pz z t’ = dt/dz =E/Pt’ = dt/dz =E/Pzz Determines, for an ensemble (sample) of N particles, the moments:Determines, for an ensemble (sample) of N particles, the moments:Averages <x> <y> etc… Averages <x> <y> etc… Second moments: variance(x) Second moments: variance(x) xx

22 = < x = < x22 - <x> - <x>2 2 > etc… > etc… covariance(x) covariance(x) xyxy = < x.y - <x><y> > = < x.y - <x><y> >

Covariance matrix Covariance matrix

M = M =

2't

't'y2

'y

't'x2

'x

'tt2t

'yt2y

'xt'xy'xxxtxy2x

...........................

............

............

............

2'y'xyx

D4

't'y'xytxD6

)Mdet(

)Mdet(

Evaluate emittance with:Evaluate emittance with: Compare Compare in in with with outout

Getting at e.g. Getting at e.g. x’t’x’t’ is essentially impossibleis essentially impossible with multiparticle bunch with multiparticle bunch measurements measurements


Systematics 15

StatisticsStatisticsMeasure a sample with N particles Measure a sample with N particles

Statistical error on <x> is Statistical error on <x> is <x><x>xxWhere Where xxis the width of the measured distributionis the width of the measured distributionStat error on width of distribution is also Stat error on width of distribution is also xxxxStat error on emittance is Stat error on emittance is 6D6D= = 6D 6D 6/N 6/N

Verify by generating M samples of N muons, that the spread of results Verify by generating M samples of N muons, that the spread of results obeys the above laws.obeys the above laws.

Input and output particles are the same! Input and output particles are the same! The emittances measured before and after the cooling channel are strongly The emittances measured before and after the cooling channel are strongly correlated. The variation of a muon transverse momentum going correlated. The variation of a muon transverse momentum going through a short channel is smaller than the spread of transverse momenta through a short channel is smaller than the spread of transverse momenta of the muons. of the muons.

This explains that This explains that ininout out ) << ) << inininin


Systematics 16

Emittance Measurement: Emittance Measurement: Results Results Cooling channel without coolingCooling channel without coolingNo No contamination, no contamination, no decay decay11 inin outout 44

ininmesmes

outoutmesmes

)1(

)1(

1mesin

1in

)1(

)1(

4mesout

out4

With 1000 samples of With 1000 samples of 10001000 accepted muons each: accepted muons each:

)1()1(

inmesin

)1)(1(outmesout

0.5%0.5% 0.6%0.6%with 1000 with 1000 with 1000 with 1000

GeneratedGeneratedMeasuredMeasured

GeneratedGeneratedMeasuredMeasured

Ratio meas/genRatio meas/gen Ratio meas/genRatio meas/gen

inin outout


Systematics 17

Figure V.4: Cooling channel efficiency, measured as the increase of the number of muons inside an acceptance of 0.1 eV.s and 1.5 cm rad (normalized), corresponding to that of the Neutrino Factory muon accelerator, as a function of the input emittance [31].

28 MeV cooling experiment (kinetic energy Ei=200 MeV)

Equilibrium emittance = 4200 mm. mrad(here)

Cooling Performance= 16%

MICE: what will it measure?


Systematics 18

Spectrometer principleSpectrometer principle

dd dd

T.O.F.T.O.F.Measure tMeasure t

With With tt 70 ps 70 ps

Three plates of, e.g.,Three plates of, e.g.,three layers of sc. fibresthree layers of sc. fibres

(diameter 0.5 mm)(diameter 0.5 mm)Measure xMeasure x11, y, y11, x, x22, y, y22, x, x33, y, y33

with precision 0.5mm/with precision 0.5mm/1212

Solenoid, B = 5 T, R = 15 cm, L > 3dSolenoid, B = 5 T, R = 15 cm, L > 3d

Need to determine, for each muon, x,y,t, and x’,y’,t’ (=pNeed to determine, for each muon, x,y,t, and x’,y’,t’ (=pxx/p/pzz, p, pyy/p/pzz, E/p, E/pzz) ) at entrance and exit of the cooling channel:at entrance and exit of the cooling channel:

Note:Note: To avoid To avoid heatingheatingexit of the solenoid exit of the solenoid

due to due to radial fieldsradial fields, the, thecooling channel has to cooling channel has to either start with the either start with the same solenoidsame solenoid, or be , or be

matchedmatched to it as well as to it as well asPossible. Possible.

(to keep B uniform on the plates)(to keep B uniform on the plates)

Extrapolate x,y,t,pExtrapolate x,y,t,pxx,p,pyy,p,pzz,,at entrance of the channel.at entrance of the channel.Make it symmetric at exit.Make it symmetric at exit.

zz


Systematics 19

Emittance Reduction:Emittance Reduction: Optimization Optimization (I)(I)(1000 (1000 ’s, No cooling, Perfect ’s, No cooling, Perfect /e Identification)/e Identification)

Optimization with respect to the distance between the 1Optimization with respect to the distance between the 1stst and the last plates and the last plates

6D6D reduction: Resolution reduction: Resolution 6D6D reduction: Bias reduction: Bias

4D4D reduction: Resolution reduction: Resolution 4D4D reduction: Bias reduction: Bias

No clear minimum, but the resolution and bias on the long. emittance reduction become No clear minimum, but the resolution and bias on the long. emittance reduction become (slightly) worse when the average muon cannot do a full turn between 1(slightly) worse when the average muon cannot do a full turn between 1 stst and last plates… and last plates…

(possibly alleviated with reconstruction tuning ?)(possibly alleviated with reconstruction tuning ?)


Systematics 20

Emittance Reduction:Emittance Reduction: Optimization Optimization (II)(II)(1000 (1000 ’s, No cooling, Perfect ’s, No cooling, Perfect /e Identification)/e Identification)

Optimization with respect to the scintillating fibre diameterOptimization with respect to the scintillating fibre diameter

6D resolution6D resolution 4D resolution4D resolution

6D bias6D bias 4D bias4D biasMeasuredMeasuredPerfect detectorsPerfect detectors

The smaller the better… Keeping the 6D bias and resolution at the % level requires aThe smaller the better… Keeping the 6D bias and resolution at the % level requires adiameter of 0.5 mm. Still acceptable with 1 mm, though. (2% bias, 1.2% resolution)diameter of 0.5 mm. Still acceptable with 1 mm, though. (2% bias, 1.2% resolution)


Systematics 21

Pion Rejection: Pion Rejection: PrinciplePrinciple

zz

zz00 zz11

0.1 X0.1 X00(Pb)(Pb)

4 X4 X00(Pb)(Pb)Measure Measure

tt00

Measure Measure tt11

Measure Measure xx00, y, y00

Measure Measure xx11, y, y11

tan,,,

0011

01

01

yxyxpE

zztt

z pE

pE

Compare withCompare with

Measured in solenoidMeasured in solenoid

-34 MeV (-34 MeV ())-31 MeV (-31 MeV ())

1.11 for 1.11 for ’s’s1.06 for 1.06 for ’s’s

1.08 for 1.08 for ’’s and s and ’s’s

CutCut

With With tt = 70 ps = 70 ps

BeamBeam

(p = 290 Mev/c)(p = 290 Mev/c)

10 metres10 metres


Systematics 22

Pion contamination in a solenoid muon beam linePion contamination in a solenoid muon beam line (muE1 or muE4) (muE1 or muE4)

set set B1B1 to 200 MeV/c to 200 MeV/c

This is the pion and muon yield This is the pion and muon yield as a function of as a function of B2B2 setting setting

ratio in beam is less than 1% if ratio in beam is less than 1% if P(B2)/P(B1) < 0.8 P(B2)/P(B1) < 0.8 TOF monitors contamination and TOF monitors contamination and reduces it to <10reduces it to <10-4-4. . => No effect on emittance => No effect on emittance or acceptance measurements.or acceptance measurements.


Systematics 23

Poor-Man Poor-Man Electron Identification Electron Identification (I)(I) At the end of the cooling channel, a few electrons from muon decays (up to 0.4% At the end of the cooling channel, a few electrons from muon decays (up to 0.4% of the particles for a 15 m-long channel) are detected in the diagnostic device.of the particles for a 15 m-long channel) are detected in the diagnostic device.

These electrons have very different momenta and directions from the parent These electrons have very different momenta and directions from the parent muons, and they spoil the measurement of the RMS emittance (6D and 4D)muons, and they spoil the measurement of the RMS emittance (6D and 4D)

About 80% of them can be rejected with kinematics, without effect on muonsAbout 80% of them can be rejected with kinematics, without effect on muons

2Tp

2Zp Poor fits for electrons (Brems)Poor fits for electrons (Brems)

ee

Large pLarge pZZ difference (p difference (pinin-p-poutout))

ee


Systematics 24

status & next stepsstatus & next steps A measurement(stat) of 6D/4D cooling can be achieved with reasonable detectorsA measurement(stat) of 6D/4D cooling can be achieved with reasonable detectors 1010-3-3 stat error requires a few 10 stat error requires a few 1055 muons muons 1% systematic bias on 6D cooling and and 0.5% bias on transverse cooling1% systematic bias on 6D cooling and and 0.5% bias on transverse cooling Three time measurements with a 50-100 ps precisionThree time measurements with a 50-100 ps precision

Two 1.5 to 2 m long, 5 T solenoids (1m useful length)Two 1.5 to 2 m long, 5 T solenoids (1m useful length) Ten (twelve?) 0.5 mm diameter scintillating fibre plates (three layers each)Ten (twelve?) 0.5 mm diameter scintillating fibre plates (three layers each) One Cerenkov detector and/or one electromagnetic calorimeter (10 XOne Cerenkov detector and/or one electromagnetic calorimeter (10 X00 Pb) Pb)

HoweverHowever, systematic effects to be addressed with further , systematic effects to be addressed with further and/more detailed simulationand/more detailed simulation

Effect of magnetic field (longitudinal and radial) imperfectionsEffect of magnetic field (longitudinal and radial) imperfections Effect of backgroundsEffect of backgrounds Effect of dead channels and misalignmentEffect of dead channels and misalignment Multiple scattering dominates resolution, biases and systematics Multiple scattering dominates resolution, biases and systematics we achieve 1% bias for nominal emittance, we achieve 1% bias for nominal emittance,

will this be the case for equilibrium emittance?will this be the case for equilibrium emittance?

Other possibilities should be studied to evaluate their potential/feasibilityOther possibilities should be studied to evaluate their potential/feasibility Thin silicon detectors instead of scintillating fibres ?Thin silicon detectors instead of scintillating fibres ? TPC-GEM ?TPC-GEM ?


Systematics 25

(Obsolete)(Obsolete) Experimental Layout Experimental Layout (I)(I)

Pb, 0.1XPb, 0.1X00 Pb, 4XPb, 4X00

Measure t, x, yMeasure t, x, yFor pion rejectionFor pion rejection

10 m10 m

Measure x, Measure x, yy

ppxx, p, pyy, p, pzz

About 5% of the About 5% of the muons arrive heremuons arrive here

Determine, with many Determine, with many ’s:’s:• Initial RMS 6D-Emittance Initial RMS 6D-Emittance ii

• Final RMS 6D-Emittance Final RMS 6D-Emittance ff

• Emittance Reduction REmittance Reduction Ri

fR

Channel with or without coolingChannel with or without coolingB = 5 T, R = 15 cm, L = 15 mB = 5 T, R = 15 cm, L = 15 m

88 MHz88 MHz 88 MHz88 MHz88 MHz88 MHz88 MHz88 MHz


Systematics 26

10 m

2 m

6 m

2 m

Incoming muon beamTOF I & II

Diffusers

Experimental Solenoid I

Experimental Solenoid II

Spectrometer trackers I

Focusing coils Liquid Hydrogen absorbers

4-cell RF cavities

Coupling coil

Electron ID

Spectrometer trackers II

TOF II

2 m


Systematics 27

Emittance Measurement: Emittance Measurement: Principle Principle (II)(II)

xx11, y, y11

xx22, y, y22

xx33, y, y33

In the transverse view, determine a circle In the transverse view, determine a circle from the three measured points:from the three measured points:

CC RR

1212 2323

Compute the transverse momentum Compute the transverse momentum from the circle radius:from the circle radius: ppTT = 0.3 B R = 0.3 B R ppxx = p = pTT sin sin ppyy = -p = -pT T coscos

Compute the longitudinal momentumCompute the longitudinal momentum from the number of turnsfrom the number of turns ppZZ = 0.3 B d / = 0.3 B d / 1212

= 0.3 B d / = 0.3 B d / 2323

= 0.3 B 2d / = 0.3 B 2d / 1313

(provides constraints for alignment)(provides constraints for alignment)

Adjust d to make 1/3 of a turn betweenAdjust d to make 1/3 of a turn between two plates two plates (d = 40 cm for B = 5 T and (d = 40 cm for B = 5 T and ppZZ = 260 MeV/c) = 260 MeV/c) on average on average

Determine E from (pDetermine E from (p22 + m + m22))1/21/2

d = pd = pzz/E /E c ctt

RR12 12 = p= pTT/E /E c cttppzz/d = p/d = pTT/ R/ R1212


Systematics 28

Emittance Measurement: Emittance Measurement: Improvement Improvement (I)(I)

zz

30 cm30 cm 35 cm35 cm 40 cm40 cm

The previous (minimal) design leads to reconstruction ambiguities for particle which The previous (minimal) design leads to reconstruction ambiguities for particle which make make a full turn between the two plates a full turn between the two plates (only two points to determine a circle)(only two points to determine a circle)

It also leads to reconstruction efficiencies and momentum resolutions dependent It also leads to reconstruction efficiencies and momentum resolutions dependent on the longitudinal momentum, which bias the emittance measurements. on the longitudinal momentum, which bias the emittance measurements.

Solution: Add one plate, make the plates not equidistantSolution: Add one plate, make the plates not equidistant

(optimal for 5 T)(optimal for 5 T)

2

24

1

2

0

2

02 and sincos

ji R

ijZ

Tij

pi i

ii

i

iip

ij

ZT

zppR

RyyRxx

To find pTo find pTT and p and pZZ, minimize:, minimize:


Systematics 29

Emittance Measurement: Emittance Measurement: Improvement Improvement (II)?(II)?

5 cm5 cm

The previous design is optimal for muons between 150 and 450 MeV/c (or any The previous design is optimal for muons between 150 and 450 MeV/c (or any dynamic range [x,3x].dynamic range [x,3x].

Decay electrons have a momentum spectrum centred a smaller values and someDecay electrons have a momentum spectrum centred a smaller values and some of them may make many turns between plates. The reconstructed momentumof them may make many turns between plates. The reconstructed momentum is between 150 and 450 MeV anyway. Very low momentum electrons cannot beis between 150 and 450 MeV anyway. Very low momentum electrons cannot be rejected later on…rejected later on…

Possible cure: Add Possible cure: Add a fifth platea fifth plate close to the fourth one in the exit diagnostic close to the fourth one in the exit diagnostic device. First try in the simulation (yesterday) looks not too good, but the device. First try in the simulation (yesterday) looks not too good, but the reconstruction needs to be tuned to this new configuration. reconstruction needs to be tuned to this new configuration. (The rest of the(The rest of the presentation uses the design with four plates.)presentation uses the design with four plates.)

zz

30 cm30 cm 35 cm35 cm 40 cm40 cm


Systematics 30

Emittance Reduction:Emittance Reduction: Optimization Optimization (III)(III)(1000 (1000 ’s, No cooling, Perfect ’s, No cooling, Perfect /e Identification)/e Identification)

Optimization with respect to the TOF resolutionOptimization with respect to the TOF resolution

time resolution is almost irrelevant (up to 500 ps) for the emittance time resolution is almost irrelevant (up to 500 ps) for the emittance measurement: no effect on the transverse emittance, and measurement: no effect on the transverse emittance, and marginal effect on the 6D emittance (resolution 0.9% marginal effect on the 6D emittance (resolution 0.9% 1.1%); 1.1%);

Quite useful to determine the timing with respect to the RF, so Quite useful to determine the timing with respect to the RF, so as to select those muons in phase with the acceleration crestas to select those muons in phase with the acceleration crest 1/101/10thth of a period (i.e., 1.1 ns for 88 MHz and 0.5 ns for 200 MHz). of a period (i.e., 1.1 ns for 88 MHz and 0.5 ns for 200 MHz). Resolution must be Resolution must be 10% of it, i.e., 100 ps for 88 MHz and 10% of it, i.e., 100 ps for 88 MHz and 50 ps for 200 MHz.50 ps for 200 MHz.

Essential to identify pions at the entrance of the channel: Indeed Essential to identify pions at the entrance of the channel: Indeed the presence of pions in the muon sample would spoil the longitudinal.the presence of pions in the muon sample would spoil the longitudinal. emittance measurement (E is not properly determined for pions, emittance measurement (E is not properly determined for pions, and part of these pions decay in the cooling channel).and part of these pions decay in the cooling channel).


Systematics 31

Pion Rejection: Pion Rejection: Optimization Optimization (II)(II)(1000 (1000 ’s, No cooling, Perfect e Identification)’s, No cooling, Perfect e Identification)

Beam Purity Requirement (confirmed with cooling)Beam Purity Requirement (confirmed with cooling)MeasuredMeasuredPerfect detectorsPerfect detectors

6D bias6D bias

6D resolution6D resolution

4D bias4D bias

4D resolution4D resolution

Need to keep the pion contamination Need to keep the pion contamination below 0.1%below 0.1% (resp 0.5%) to have a negligible (resp 0.5%) to have a negligible effect on the 6D (resp. 4D) emittance reduction resolution and bias. It corresponds effect on the 6D (resp. 4D) emittance reduction resolution and bias. It corresponds to a beam contamination to a beam contamination smaller than 10%smaller than 10% (50%) when entering the experiment. (50%) when entering the experiment.


Systematics 32

Pion Rejection: Pion Rejection: Optimization Optimization (III)(III)(1000 (1000 ’s, Perfect e Identification)’s, Perfect e Identification)

Beam Purity Requirement with CoolingBeam Purity Requirement with Cooling (Four 88 MHZ cavities)(Four 88 MHZ cavities)

1) 6D-Cooling and Resolution 2) Statistical significance with 1000 1) 6D-Cooling and Resolution 2) Statistical significance with 1000 ’s’s

Pion cut at 1.00Pion cut at 1.00Pion cut at 0.99Pion cut at 0.99

NoNoEffectEffect

(in the beam)(in the beam)

6D Cooling6D Cooling

ResolutionResolution


Systematics 33

Pion Rejection: Pion Rejection: Optimization Optimization (IV)(IV)(1000 (1000 ’s, Perfect e Identification)’s, Perfect e Identification)

Beam Purity Requirement with CoolingBeam Purity Requirement with Cooling (Four 88 MHZ cavities)(Four 88 MHZ cavities)

No EffectNo Effect

Pion cut at 1.00Pion cut at 1.00Pion cut at 0.99Pion cut at 0.99

(in the beam)(in the beam)

1) Transverse-Cooling and Resolution 2) Statistical significance with 1000 1) Transverse-Cooling and Resolution 2) Statistical significance with 1000 ’s’s




Systematics 34

Pion Rejection: Pion Rejection: Optimization Optimization (I)(I)(1000 (1000 ’s, No cooling, Perfect e Identification)’s, No cooling, Perfect e Identification)

Optimization with respect to the TOF resolutionOptimization with respect to the TOF resolution

Assume an initial beam formed Assume an initial beam formed with 50% muons and 50% pionswith 50% muons and 50% pions (same momentum spectrum) (same momentum spectrum)

Vary the T.O.F. resolution Vary the T.O.F. resolution

Apply the previous pion cutApply the previous pion cut (E/p)/(E(E/p)/(E/p) < 1.00 and check /p) < 1.00 and check the remaining pion fraction the remaining pion fraction in a 10,000 muon sample.in a 10,000 muon sample.

Remaining pion fractionRemaining pion fraction

Because of the beam momentum spread and of the additional spreadBecause of the beam momentum spread and of the additional spreadintroduced by the 4Xintroduced by the 4X00 Pb plate, the Pb plate, the // separation does not improve separation does not improve

for a resolution better than for a resolution better than 100-150 ps100-150 ps (for a path length of 10 m) (for a path length of 10 m)


Systematics 35

Poor-Man Poor-Man Electron Identification Electron Identification (II)(II)(1000 (1000 ’s, with cooling, 0 to 20 RF cavities)’s, with cooling, 0 to 20 RF cavities)

1) 6D-Cooling and Resolution 2) Statistical significance with 1000 1) 6D-Cooling and Resolution 2) Statistical significance with 1000 ’s’s• GeneratedGenerated• Measured, perfect e-IdMeasured, perfect e-Id• Measured, poor man e-IdMeasured, poor man e-Id



Need better e-Id to get Need better e-Id to get back to the red curve!back to the red curve!• Cerenkov detector (1/1000)Cerenkov detector (1/1000) • El’mgt calorimeter (?)El’mgt calorimeter (?)

Remaining electron fractionRemaining electron fraction3 103 10-4-4 6 10 6 10-4-4 8 10 8 10-4-4


Systematics 36

Poor-Man Poor-Man Electron Identification Electron Identification (III)(III)(1000 (1000 ’s, with cooling, 0 to 20 RF cavities)’s, with cooling, 0 to 20 RF cavities)

1) Transverse Cooling and Resolution 2) Statistical significance with 1000 1) Transverse Cooling and Resolution 2) Statistical significance with 1000 ’s’s• GeneratedGenerated• Measured, perfect e-IdMeasured, perfect e-Id• Measured, poor man e-IdMeasured, poor man e-Id Remaining electron fractionRemaining electron fraction

3 103 10-4-4 6 10 6 10-4-4 8 10 8 10-4-4



No need for more e IdNo need for more e IdFor the transverseFor the transverse

cooling measurementcooling measurement

alain blondel, mice collab. ral 8-10 july 2002 systematics 1 experimental systematics outline...

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