1 Measurement of particle production from the MICE target Kenny Walaron, Paul Soler University of Glasgow

2 Goals 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 dipping into ISIS Main goal: demonstration of a working target dipping into ISIS 1 st prototype run with slower acceleration 1 st prototype run with slower acceleration Target design and performance covered by target summary (see P. Smith plenary talk). Target design and performance covered by target summary (see P. Smith plenary talk). Bias of this talk is particle production: relationship between singles production into MICE and ISIS losses Bias of this talk is particle production: relationship between singles production into MICE and ISIS losses Compare singles/p.o.t calculated from Monte Carlo (used for beam normalisation) and data. Compare singles/p.o.t calculated from Monte Carlo (used for beam normalisation) and data. Investigate singles production as a function of average target depth in final 2ms before extraction Investigate singles production as a function of average target depth in final 2ms before extraction All essential unknowns for MICE previously not studied All essential unknowns for MICE previously not studied Many thanks to everyone who took part in test (ie. Sheffield and RAL people working on target etc.) Many thanks to everyone who took part in test (ie. Sheffield and RAL people working on target etc.)

3 Target 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

4 Signals 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 injection  extraction + 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

5 Simulations 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 cm 2 GEANT4 target distribution in 1600 cm 2

6 MARS momentum distributions of particle species at U/S face of scintillator Unshielded shielded

7 GEANT4 momentum distributions of particle species at U/S face of scintillator Unshielded shielded

8 Charged particle detection efficiency To  give 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 distributionGEANT4 target distribution

9 Neutron detection efficiency Non-thermal neutron cross-sections very small Non-thermal neutron cross-sections very small We calculated from parameterisations found in Knoll that detection efficiency at 30 MeV = 1.4% through 1cm of plastic. Knock on proton efficiency from previous work roughly >95% We calculated from parameterisations found in Knoll that detection efficiency at 30 MeV = 1.4% through 1cm of plastic. Knock on proton efficiency from previous work roughly >95% From simulations (GEANT4=119 MARS=195) neutrons below 30MeV. X-sect is rapidy falling even a 30MeV/c, at > it is negligibly small From simulations (GEANT4=119 MARS=195) neutrons below 30MeV. X-sect is rapidy falling even a 30MeV/c, at > it is negligibly small Hence in our MC samples we effectively remove all neutrons when estimating detector response Hence in our MC samples we effectively remove all neutrons when estimating detector response Accurate to 3% in 0<En<30 MeV range

10 Run summary Data recorded for stationary (fixed position) target and pulsed target (varying delay on start of pulse) Data recorded for stationary (fixed position) target and pulsed target (varying delay on start of pulse) Statistics fairly small. Statistics fairly small. Second target run in December was cancelled Second target run in December was cancelled Static target stats too low to say anything Static target stats too low to say anything

11 Detector Analysis 1 Code written to convert oscilloscope trace files to more useful ROOT Trees. Code written to convert oscilloscope trace files to more useful ROOT Trees. Different time bases on scopes complicate things: expanded “slow” scope signals to match finer resolution of LeCroy scope. No loss of information. Different time bases on scopes complicate things: expanded “slow” scope signals to match finer resolution of LeCroy scope. No loss of information. Discrimination of PMT signals implemented: Discrimination of PMT signals implemented: Discriminator level taken from noise distributions for each individual PMT: 3  level chosen. Discriminator level taken from noise distributions for each individual PMT: 3  level chosen.

12 Detector Analysis 2 Clusterisation algorithm: consecutive signals above discriminator level constitute a cluster in data. Clusterisation algorithm: consecutive signals above 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 clusters which match to a tolerance of +/- 10ns. Determined by inspection of data. Coincident hits in detectors determined as those clusters which match to a tolerance of +/- 10ns. Determined by inspection of data. Additional analysis performed to try to identify protons vs MIPS. Reconstruction of saturated pulse heights by fitting to tail, total voltage (hence charge) of pulse distributions, pulse length distributions calculated. No features evident to use as PID handle. Additional analysis performed to try to identify protons vs MIPS. Reconstruction of saturated pulse heights by fitting to tail, total voltage (hence charge) of pulse distributions, pulse length distributions calculated. No features evident to use as PID handle. Discrimination level moved to 5  to check effect. No reduction in number of coincidences. 2  level showed reduction Discrimination level moved to 5  to check effect. No reduction in number of coincidences. 2  level showed reduction

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

14 The last 2ms Last 2ms is when MICE target will be inserted during proper running so we focus on this Last 2ms is when MICE target will be inserted during proper running so we focus on this Measured mean number of coincidences in last 2ms for both detectors. Measured mean number of coincidences in last 2ms for both detectors. Measured average beam-loss in straight7 in last 2ms (monitors which will limit MICE). Measured average beam-loss in straight7 in last 2ms (monitors which will limit MICE). Calculated mean kinetic energy in last 2ms ( MeV) Calculated mean kinetic energy in last 2ms ( MeV) Mean target depth in last 2ms Mean target depth in last 2ms These quantities are calculated for each dip-condition. These quantities are calculated for each dip-condition. Momentum evolution (blue, MeV/c) and K.E evolution (red, MeV) over 10ms P (MeV/c) K.E (MeV) Time spill (s)

15 Relationship between singles detected and beam loss Unshielded detectorShielded detector Calculated mean number of hits per target dip for all 7 target conditions in the last 2ms. Remember, different target delay = different ISIS beam interception Calculated mean number of hits per target dip for all 7 target conditions in the last 2ms. Remember, different target delay = different ISIS beam interception Calculated the mean total beam loss in the last 2ms for each of these target conditions (50 mV beam loss trips ISIS!). Calculated the mean total beam loss in the last 2ms for each of these target conditions (50 mV beam loss trips ISIS!).

16 Relationship between singles into MICE acceptance and beam loss Unshielded detectorShielded detector Detector angular acceptance scaled to the MICE angular acceptanceDetector angular acceptance scaled to the MICE angular acceptance Important result as we now have a measure of how much ISIS beam we can reasonably take before we trip ISIS and how this translates to particle yieldsImportant result as we now have a measure of how much ISIS beam we can reasonably take before we trip ISIS and how this translates to particle yields

17 Conclusion 1: Coupling of MICE to ISIS The results of least squares linear fits to the data give the following relations: The results of least squares linear fits to the data give the 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 ISIS They 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 2ms 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 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

18 Comparison of singles per proton on target from simulation and data To normalise beam rates along MICE beamline we use the GEANT4 and MARS target simulations To normalise beam rates along MICE beamline we use the GEANT4 and MARS target simulations Monte Carlo consists of 10 Million p.o.t. from which we calculate the number of singles/p.o.t into MICE Monte Carlo consists of 10 Million p.o.t. from which we calculate the number of singles/p.o.t into MICE A huge amount rests on this. Detector rates, good mu+, run schedule etc. A huge amount rests on this. Detector rates, good mu+, run schedule etc. Codes show some discrepancy and we believe the average of these numbers blindly (or at least with cloudy vision). Both numbers could be out by some factor. Codes show some discrepancy and we believe the average of these numbers blindly (or at least with cloudy vision). Both numbers could be out by some factor. We will try to calculate this number from data and compare to simulation We will try to calculate this number from data and compare to simulation This will benchmark our assumptions and see if we can provide some spectacles. This will benchmark our assumptions and see if we can provide some spectacles.

19 Singles/p.o.t calculation In simulations, calculation is the pure Monte Carlo truth singles intecepting detector x efficiency of detection normalised to 10Million p.o.t In simulations, calculation is the pure Monte Carlo truth singles intecepting detector x efficiency of detection normalised to 10Million p.o.t From the data the number of singles is the number of coincident hits following the event selection of clusters etc/p.o.t From the data the number of singles is the number of coincident hits following the event selection of clusters etc/p.o.t We get number of ISIS protons intercepting target from beam loss in super-period 7. We get number of ISIS protons intercepting target from beam loss in super-period 7. Calibration of number of protons lost  signal at SP7 monitors via communication with Di Wright. Calibration of number of protons lost  signal at SP7 monitors via communication with Di Wright. At 780 MeV (9ms) = 3.5x10^14 Vs/p, At 800 MeV (10ms) = 3.8x10^14Vs/p At 780 MeV (9ms) = 3.5x10^14 Vs/p, At 800 MeV (10ms) = 3.8x10^14Vs/p If one takes value at 9ms one can calculate number of protons hitting beam under assumption every proton lost intercepts target. If one takes value at 9ms one can calculate number of protons hitting beam under assumption every proton lost intercepts target.

20 Conclusion 2: Singles per p.o.t comparison:- Validating codes Results given below. Results given below. Statistical errors only (Poisson) in Monte Carlo Statistical errors only (Poisson) in Monte Carlo Error in data: combination of statistical error and 8% calibration error (from assumption of value at 9ms) Error in data: combination of statistical error and 8% calibration error (from assumption of value at 9ms) Excellent agreement between data and MARS. Excellent agreement between data and MARS. Worse agreement with GEANT4 Worse agreement with GEANT4 Result from data determined independently to Monte Carlo Result 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 (Unshielded)(x10 -8 ) Singles/pot (Shielded)(x10 -8 ) MARS GEANT DATA PRELIMINARY!

21 Mean target position in last 2ms as function of target depth ISIS transverse profile previously not known ISIS transverse profile previously not known We try to obtain an estimate of this from the measured beam loss for different target trajectories We try to obtain an estimate of this from the measured beam loss for different target trajectories We try to establish firstly a relationship between beam loss and mean target depth. We try to establish firstly a relationship between beam loss and mean target depth. Translate this into a relationship between charged particle singles into MICE acceptance as a function of target depth Translate this into a relationship between charged particle singles into MICE acceptance as a function of target depth Not ideal as we can only give the beam loss and hence particle yield assuming an average target depth over the entire 2ms. Not ideal as we can only give the beam loss and hence particle yield assuming an average target depth over the entire 2ms. Compared to the amount of information available previously (ZERO) this is still useful Compared to the amount of information available previously (ZERO) this is still useful

22 Mean target position in last 2ms as function of target depth One can see sharp ISIS transverse beam profile One can see sharp ISIS transverse beam profile Also shown is the charged particle yield into the MICE acceptance assuming target is held at the depths shown for the entire 8-10ms Also shown is the charged particle yield into the MICE acceptance assuming target is held at the depths shown for the entire 8-10ms Important as it shows how sensitive the rate into the MICE acceptance is on target depth. Important as it shows how sensitive the rate into the MICE acceptance is on target depth.

23 Summary Target test very useful Target test very useful Established relationship between beam loss and particle production into MICE beamline Established relationship between beam loss and particle production into MICE beamline Validated Monte Carlo simulations used for calculating beamline rates and “good mu+” rates into MICE Validated Monte Carlo simulations used for calculating beamline rates and “good mu+” rates into MICE Imaged ISIS transverse profile in the final 2ms and investigated relationship between target insertion and particle yields into MICE Imaged ISIS transverse profile in the final 2ms and investigated relationship between target insertion and particle yields into MICE