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Measurement of particle Measurement of particle production from the MICE production from the MICE

target target

Kenny Walaron, Paul SolerKenny Walaron, Paul Soler

University of GlasgowUniversity of Glasgow

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Goals of the testGoals of the test Target test carried out 1-2 Nov 2006 in ISIS ring. Target test carried out 1-2 Nov 2006 in ISIS ring. Main goal: demonstration of a working target Main goal: demonstration of a working target

dipping into ISIS dipping into ISIS 11stst prototype run with slower acceleration prototype run with slower acceleration Target design and performance covered by target Target design and performance covered by target

summary (see P. Smith plenary talk).summary (see P. Smith plenary talk). Bias of this talk is particle production: relationship Bias of this talk is particle production: relationship

between singles production into MICE and ISIS between singles production into MICE and ISIS losseslosses

Compare singles/p.o.t calculated from Monte Carlo Compare singles/p.o.t calculated from Monte Carlo (used for beam normalisation) and data. (used for beam normalisation) and data.

Investigate singles production as a function of Investigate singles production as a function of average target depth in final 2ms before extractionaverage target depth in final 2ms before extraction

All essential unknowns for MICE previously not All essential unknowns for MICE previously not studiedstudied

Many thanks to everyone who took part in test (ie. Many thanks to everyone who took part in test (ie. Sheffield and RAL people working on target etc.)Sheffield and RAL people working on target etc.)

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Target test set-upTarget test set-up

• 2 sets of detectors:

1 shielded pair of scint.+PMTS (MUSCAT) with HV

1 unshielded pair of detectors (Glasgow)+Low V.

• Scope DAQ and readout to Linux PC via GPIB

• Signals from ISIS and target

Target installed in ISIS

Schematic of unshielded detectors

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Signals and DAQSignals and DAQ•Thanks to Bill Murray for writing DAQ!

•Non-detector signals to DAQ were: Total beam loss, beam loss from super-period 7, target position, ISIS beam current

•“Slow” signals did not require fine grained resolution. More important to sample over entire injectionextraction + a little extra each side

•Detector signals need finer resolution such that one can resolve individual pulses. Borrowed LeCroy “super-scope” able to provide the 10 ns resolution and memory depth to sample whole 10ms

•All slow signals and detector signals recorded to ROOT histograms per run

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Simulations of target-testSimulations of target-test

•Motivation: To compare singles/p.o.t into MICE angular acceptance

•MARS and GEANT4 distributions from target weighted into area twice MICE acceptance. GEANT4 tracking through air and plastic using Monte Carlo distributions as input.

•Simulations were 10 Million, 800MeV/c KE protons incident on MICE target . This energy corresponds to proton energy at extraction

•These are the same target distributions used to normalise beam rates along beamline

MARS target distribution in 1600 cm2

GEANT4 target distribution in 1600 cm2

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MARS momentum distributions of MARS momentum distributions of particle species at U/S face of particle species at U/S face of

scintillatorscintillatorUnshielded shielded

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GEANT4 momentum distributions of GEANT4 momentum distributions of particle species at U/S face of particle species at U/S face of

scintillatorscintillatorUnshielded shielded

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Charged particle detection Charged particle detection efficiencyefficiency

•Togive an estimation of the efficiency of detecting charged particles we look at number of particles which pass through both scintillators.

•Charge particle efficiency in simulations is defined to be % of singles incident on upstream face that are present on downstream face

•Vast majority of charged particles are protons. Efficiencies for other charged species have very low statistics.

MARS target distribution GEANT4 target distribution

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Neutron detection efficiencyNeutron detection efficiency

• Non-thermal neutron cross-sections very smallNon-thermal neutron cross-sections very small• We calculated from parameterisations found in Knoll that We calculated from parameterisations found in Knoll that

detection efficiency at 30 MeV = 1.4% through 1cm of detection efficiency at 30 MeV = 1.4% through 1cm of plastic. Knock on proton efficiency from previous work plastic. Knock on proton efficiency from previous work roughly >95%roughly >95%

• From simulations (GEANT4=119 MARS=195) neutrons From simulations (GEANT4=119 MARS=195) neutrons below 30MeV. X-sect is rapidy falling even a 30MeV/c, at > below 30MeV. X-sect is rapidy falling even a 30MeV/c, at > it is negligibly smallit is negligibly small

• Hence in our MC samples we effectively remove all Hence in our MC samples we effectively remove all neutrons when estimating detector response neutrons when estimating detector response

Accurate to 3% in 0<En<30 MeV range

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Run summaryRun summary• Data recorded for stationary (fixed position) target Data recorded for stationary (fixed position) target

and pulsed target (varying delay on start of pulse) and pulsed target (varying delay on start of pulse)

• Statistics fairly small. Statistics fairly small. • Second target run in Second target run in

December was cancelledDecember was cancelled• Static target stats too Static target stats too

low to say anythinglow to say anything

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Detector Analysis 1Detector Analysis 1• Code written to convert oscilloscope trace Code written to convert oscilloscope trace

files to more useful ROOT Trees. files to more useful ROOT Trees. • Different time bases on scopes complicate Different time bases on scopes complicate

things: expanded “slow” scope signals to things: expanded “slow” scope signals to match finer resolution of LeCroy scope. No match finer resolution of LeCroy scope. No loss of information.loss of information.

• Discrimination of PMT signals implemented:Discrimination of PMT signals implemented:• Discriminator level taken from noise distributions Discriminator level taken from noise distributions

for each individual PMT: 3for each individual PMT: 3level chosen.level chosen.

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Detector Analysis 2Detector Analysis 2 • Clusterisation algorithm: consecutive signals above Clusterisation algorithm: consecutive signals above

discriminator level constitute a cluster in data. discriminator level constitute a cluster in data. • All 4 PMT channels discriminated and “clusterised”.All 4 PMT channels discriminated and “clusterised”.• Coincident hits in detectors determined as those Coincident hits in detectors determined as those

clusters which match to a tolerance of +/- 10ns. clusters which match to a tolerance of +/- 10ns. Determined by inspection of data.Determined by inspection of data.

• Additional analysis performed to try to identify Additional analysis performed to try to identify protons vs MIPS. Reconstruction of saturated pulse protons vs MIPS. Reconstruction of saturated pulse heights by fitting to tail, total voltage (hence charge) heights by fitting to tail, total voltage (hence charge) of pulse distributions, pulse length distributions of pulse distributions, pulse length distributions calculated. No features evident to use as PID handle.calculated. No features evident to use as PID handle.

• Discrimination level moved to 5Discrimination level moved to 5to check effect. No to check effect. No reduction in number of coincidences. 2reduction in number of coincidences. 2level level showed reductionshowed reduction

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Total coincident hitsTotal coincident hits

• Total number of coincident hits for both Total number of coincident hits for both detectors over all target conditions. Red = detectors over all target conditions. Red = pulsed runs, blue = held runspulsed runs, blue = held runs

Unshielded detectors Shielded detectors

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The last 2msThe last 2ms • Last 2ms is when MICE target Last 2ms is when MICE target

will be inserted during proper will be inserted during proper running so we focus on thisrunning so we focus on this

• Measured mean number of Measured mean number of coincidences in last 2ms for coincidences in last 2ms for both detectors. both detectors.

• Measured average beam-loss Measured average beam-loss in straight7 in last 2ms in straight7 in last 2ms (monitors which will limit (monitors which will limit MICE). MICE).

• Calculated mean kinetic Calculated mean kinetic energy in last 2ms (778energy in last 2ms (778+22+22

-64-64 MeV)MeV)

• Mean target depth in last 2msMean target depth in last 2ms• These quantities are These quantities are

calculated for each dip-calculated for each dip-condition.condition.

Momentum evolution (blue, MeV/c) and K.E evolution (red, MeV) over 10ms

P (MeV/c)

K.E (MeV)

Time spill (s)

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Relationship between singles Relationship between singles detected and beam lossdetected and beam loss

Unshielded detector

Shielded detector

• Calculated mean number of hits per target dip for all 7 target Calculated mean number of hits per target dip for all 7 target conditions in the last 2ms. Remember, different target delay = conditions in the last 2ms. Remember, different target delay = different ISIS beam interception different ISIS beam interception

• Calculated the mean total beam loss in the last 2ms for each Calculated the mean total beam loss in the last 2ms for each of these target conditions (50 mV beam loss trips ISIS!).of these target conditions (50 mV beam loss trips ISIS!).

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Relationship between singles into Relationship between singles into MICE acceptance and beam lossMICE acceptance and beam loss

Unshielded detector

Shielded detector

•Detector angular acceptance scaled to the MICE angular Detector angular acceptance scaled to the MICE angular acceptanceacceptance

•Important result as we now have a measure of how much ISIS Important result as we now have a measure of how much ISIS beam we can reasonably take before we trip ISIS and how this beam we can reasonably take before we trip ISIS and how this translates to particle yieldstranslates to particle yields

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Conclusion 1: Coupling of MICE to Conclusion 1: Coupling of MICE to ISISISIS

• The results of least squares linear fits to the data give the The results of least squares linear fits to the data give the following relations:following relations:

• These relations are important as they provide first actual coupling of MICE to ISIS.These relations are important as they provide first actual coupling of MICE to ISIS.• They can be used to quantify actual yields from the target into MICE beamline in terms of the effect on ISISThey can be used to quantify actual yields from the target into MICE beamline in terms of the effect on ISIS• Can (although not in this talk) be used as input into run planning etc. as we now have an upper limit of charged singles into MICE in last 2msCan (although not in this talk) be used as input into run planning etc. as we now have an upper limit of charged singles into MICE in last 2ms• At 50mV* beam loss we expect 2.5 x10^5 charged singles into MICE acceptance At 50mV* beam loss we expect 2.5 x10^5 charged singles into MICE acceptance

*ISIS BL limit applicable to MICE

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Comparison of singles per proton on target from simulation and

data• To normalise beam rates along MICE beamline we use the To normalise beam rates along MICE beamline we use the

GEANT4 and MARS target simulations GEANT4 and MARS target simulations • Monte Carlo consists of 10 Million p.o.t. from which we Monte Carlo consists of 10 Million p.o.t. from which we

calculate the number of singles/p.o.t into MICEcalculate the number of singles/p.o.t into MICE• A huge amount rests on this. Detector rates, good mu+, run A huge amount rests on this. Detector rates, good mu+, run

schedule etc.schedule etc.• Codes show some discrepancy and we believe the average Codes show some discrepancy and we believe the average

of these numbers blindly (or at least with cloudy vision). of these numbers blindly (or at least with cloudy vision). Both numbers could be out by some factor.Both numbers could be out by some factor.

• We will try to calculate this number from data and compare We will try to calculate this number from data and compare to simulationto simulation

• This will benchmark our assumptions and see if we can This will benchmark our assumptions and see if we can provide some spectacles.provide some spectacles.

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Singles/p.o.t calculationSingles/p.o.t calculation

• In simulations, calculation is the pure Monte Carlo truth In simulations, calculation is the pure Monte Carlo truth singles intecepting detector x efficiency of detection singles intecepting detector x efficiency of detection normalised to 10Million p.o.tnormalised to 10Million p.o.t

• From the data the number of singles is the number of From the data the number of singles is the number of coincident hits following the event selection of clusters coincident hits following the event selection of clusters etc/p.o.tetc/p.o.t

• We get number of ISIS protons intercepting target from We get number of ISIS protons intercepting target from beam loss in super-period 7.beam loss in super-period 7.

• Calibration of number of protons lost Calibration of number of protons lost signal at SP7 signal at SP7 monitors via communication with Di Wright.monitors via communication with Di Wright.

• At 780 MeV (9ms) = 3.5x10^14 Vs/p, At 800 MeV (10ms) = At 780 MeV (9ms) = 3.5x10^14 Vs/p, At 800 MeV (10ms) = 3.8x10^14Vs/p3.8x10^14Vs/p

• If one takes value at 9ms one can calculate number of If one takes value at 9ms one can calculate number of protons hitting beam under assumption every proton lost protons hitting beam under assumption every proton lost intercepts target.intercepts target.

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Conclusion 2: Singles per p.o.t Conclusion 2: Singles per p.o.t comparison:- Validating codescomparison:- Validating codes

• Results given below.Results given below.• Statistical errors only (Poisson) in Monte CarloStatistical errors only (Poisson) in Monte Carlo• Error in data: combination of statistical error and 8% Error in data: combination of statistical error and 8%

calibration error (from assumption of value at 9ms)calibration error (from assumption of value at 9ms)

• Excellent agreement between data and MARS.Excellent agreement between data and MARS.• Worse agreement with GEANT4Worse agreement with GEANT4• Result from data determined independently to Monte CarloResult from data determined independently to Monte Carlo• Validation of charged singles yield at MICE production angle.Validation of charged singles yield at MICE production angle.

Singles/pot Singles/pot (Unshielded)(x10(Unshielded)(x10-8-8))

Singles/pot Singles/pot (Shielded)(x10(Shielded)(x10-8-8))

MARSMARS 1.70+-0.101.70+-0.10 1.52+-0.101.52+-0.10

GEANT4GEANT4 2.47+-0.122.47+-0.12 1.61+-0.101.61+-0.10

DATADATA 1.59+-0.271.59+-0.27 1.29+-0.241.29+-0.24

PRELIMINARY!PRELIMINARY!

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Mean target position in last 2ms Mean target position in last 2ms as function of target depthas function of target depth

• ISIS transverse profile previously not knownISIS transverse profile previously not known• We try to obtain an estimate of this from the measured We try to obtain an estimate of this from the measured

beam loss for different target trajectoriesbeam loss for different target trajectories• We try to establish firstly a relationship between beam loss We try to establish firstly a relationship between beam loss

and mean target depth.and mean target depth.• Translate this into a relationship between charged particle Translate this into a relationship between charged particle

singles into MICE acceptance as a function of target depthsingles into MICE acceptance as a function of target depth• Not ideal as we can only give the beam loss and hence Not ideal as we can only give the beam loss and hence

particle yield assuming an average target depth over the particle yield assuming an average target depth over the entire 2ms.entire 2ms.

• Compared to the amount of information available Compared to the amount of information available previously (ZERO) this is still usefulpreviously (ZERO) this is still useful

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Mean target position in last 2ms Mean target position in last 2ms as function of target depthas function of target depth

• One can see sharp ISIS transverse beam profileOne can see sharp ISIS transverse beam profile• Also shown is the charged particle yield into the MICE Also shown is the charged particle yield into the MICE

acceptance assuming target is held at the depths shown for acceptance assuming target is held at the depths shown for the entire 8-10msthe entire 8-10ms

• Important as it shows how sensitive the rate into the MICE Important as it shows how sensitive the rate into the MICE acceptance is on target depth.acceptance is on target depth.

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SummarySummary

• Target test very usefulTarget test very useful• Established relationship between beam loss and Established relationship between beam loss and

particle production into MICE beamlineparticle production into MICE beamline• Validated Monte Carlo simulations used for Validated Monte Carlo simulations used for

calculating beamline rates and “good mu+” rates calculating beamline rates and “good mu+” rates into MICEinto MICE

• Imaged ISIS transverse profile in the final 2ms Imaged ISIS transverse profile in the final 2ms and investigated relationship between target and investigated relationship between target insertion and particle yields into MICEinsertion and particle yields into MICE