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Livio VerraItalians Summer Student, Final PresentationSupervisor: Mandy RominskySeptember 27th, 2017
LAPPD ProjectTest Beam Facility MC6-7 Simulation
• Mid Term recap:– LAPPD project;– MC6 & MC7 simulation;
• Progress:– Theoretical prevision;– Simulation tricks;
• Results;
• Conclusions.
Summary
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Goal of the project is manufacturing <10 pstime resolution photodetector.
Key elements:
• Glass body, minimal feedthroughs;• MCPs made using atomic layer
deposition;• Transmission line anode;• Fast and economical front-end
electronics;• Large area, flat panel photocathode.
Large Area Picosend PhotoDetector:
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• Fast source: a psec source of many photons (e.g. Cherenkov light from a charged particle traversing radiator or the entrance window of a photodetector);
• psec-level pixel-size (10-20 μm pores in MCP);• High gain: the gain has to be high enough that a single
photon triggers, i.e: the first photon “in” determines the leading edge of the pulse and consequently the timing.
Criteria for sub-psec timing:
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• Time of Flight LAPPD will be tested at Fermilab Test Beam Facility so as to prove high time resolution:
• Having a precise knowledge of beam’s shape, energy, composition through experimental setup is necessary in order to position detectors in the most convenient location.
MC6 & MC7 simulations
My work:
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• Main Injector provides 120 GeV/c protons in 4.2 second-spills, with approximately 60 seconds of repetition rate.
• Spills are made up of batches: 7 batches covered 11,2 μs (size of Main Injector); every batch is composed by 84 RF buckets (size of booster).
• Only the first batch over 7 has particles.
Where does FTBF receive beam from?
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• The beam is transferred till M02 enclosure: it’s then split in two beams so as to deliver particles to both MTest and Mcenter.
Test Beam Facility
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120GeV/cproton beam
MC6&MC7
• 120 GeV/c protons hit the copper target: then they are guided (with interaction products) along the beam line.
• MC6 provides a low-intensity beam, of a chosen mean momentum, parallel to the floor.
MC6 Structure
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Cutarget
Quadrupoles
Dipoles Collimators
MC6 simulation
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• Target cage;• Collimators;• Q3 quadrupoles;• Dipoles;• Q4 quadrupoles;• Trims
Simulationprogram:G4beamline(Geant4implementation)
• Mean Momentum of particles is selected by:– Momentum Collimator: it physically stops above 90 GeV/c
momentum particles (most of the beam);– Dipoles: they are all fed by the same power supply, hence they
provide the same field, set for selecting mean momentum.
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2million-eventssimulation64GeV/csetup
2million-eventssimulation8GeV/csetup
PDGid0 500 1000 1500 2000
Ptot
[MeV
/c]
10000
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Ptot vs. PDGid
PDGid0 500 1000 1500 2000
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[MeV
/c]
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120310×
Ptot vs. PDGid
• Selecting momentum implies selecting species:
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PDGid0 500 1000 1500 2000
counts
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PDGid
Note:electronandgammatracksarekilledforreducingsimulationrunningtime
2million-eventssimulation64GeV/csetup
2million-eventssimulation8GeV/csetup
PDGid0 500 1000 1500 2000
counts
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PDGid
• MC7 has calibrated instrumentation (counters, Cherenkov detectors, etc.) and can be customized for fitting experimental requirements;
• In this case, MC7 is made up of some detectors, a copper target (approximately 6 m downstream the last MC6 quad) and a collimator;
• LAPPD setup will be straight after the collimator, in the beam direction, so as to take advantage of the shielding effect.
MC7 structure
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MC7 simulation
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Collimator
Beam from MC6
Copper target
ToF setup
• Considering particles momentum and distance, it’s possible to calculate the system capability of solving different species;
• Couples of interest are:– π+ / μ+;– π+ / K+;– π- / e-;
• Calculations have been executed considering particles travelling in vacuum along a straight path.
Theoretical previsions:
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π+ / μ+ resolution plot:
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π+ / K+ resolution plot:
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π- / e- resolution plot:
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• 2-million-event simulation requires 12 hours running;
• Simulating one spill (~ 500 millions particles) would take 3000 hours;
• For having statistically significant results, avoiding too long running time:– Consider spatial and momentum distribution of every species
reaching the end of MC6 in 2-million-event simulation;– Proportionally calculate the number of events coming to MC7;– Run simulations equivalent to 500-million-event one.
Simulation tricks:
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2millionsevents Extractinginfofromparticles
gettingthroughbothVirtualDetectors
Sendingsimulationforeachspecies,usingdistributionsgainedbefore
• Analysis code takes as input two selected Time-of-Flight VirtualDetectors and considers particles hitting both of them;
• It calculates β value using Time of Flight and position of the hit;
• It calculates error 𝚫β propagating errors on measurements:– 1 ps of time resolution;– 7 μm on transversal positions;– 8 mm on longitudinal position (thickness of the Cherenkov
glass).
Results:
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8 GeV/c setup results:
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beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
counts
0
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beta
beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
counts
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beta
beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
counts
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beta
beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
counts
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beta
5m 7.5m(usingthefirstDetector)
7.5m(thefirstTimeofFlightis7.5mapartfromthefirstDetector)
15m
beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
counts
0
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beta
beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
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beta
16 GeV/c setup results:
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beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
counts
0
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beta
betaEntries 87Mean 0.9992RMS 0.0008304
0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 10
10
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70beta
Entries 87Mean 0.9992RMS 0.0008304
beta
beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
counts
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beta
5m
7.5m(thefirstTimeofFlightis7.5mapartfromthefirstDetector)
15m
7.5m(usingthefirstdetector)
64 GeV/c setup results:
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beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
counts
0
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beta
beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
counts
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beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
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beta
beta0.99 0.991 0.992 0.993 0.994 0.995 0.996 0.997 0.998 0.999 1
counts
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beta
5m
7.5m(thefirstTimeofFlightis7.5mapartfromthefirstDetector)
15m
7.5m(usingthefirstdetector)
• MCenter provides a large momentum range and the possibility of having a low intensity beam;
• Choosing a low momentum setup, it’s possible to have a quite “clean” muon beam;
• Simulation results are confirmed by real historic data: it’s precise and reliable;
• The farer detectors are, the more precise measurements are, and the more ”clean” the beam is.
Conclusions:
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• LAPPD Time-of-Flight setup will consist of three detectors;
• Since the beam composition and properties, and MC7 structure, the best placement will be 7.5 m of distance between detectors;
• Hence, the following configurations will be available:– 7.5 m, using detectors 1 & 2;– 15 m, using detectors 1 & 3;– 7.5 m, using detectors 2 & 3.
Conclusions:
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• Database of MC6 & MC7 outlines;
• Simulation of beam lines.
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Conclusion: What I gave Fermilab:
• New knowledge about particle accelerators and transfer systems;
• Taste of working in a real scientific environment;
• PATIENCE.
Conclusion: What Fermilab gave me:
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Many thanks for your attention
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