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Detector Timing. Using timing in detector elements to suppress backgrounds arising from neighboring bunches requires some care. Transit time for high energy muon is ~8.5 ns through barrel calorimeter at 90 º . Hadronic showers create many long-lived neutrons and other decay particles.
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Detector Timing • Using timing in detector elements to suppress backgrounds arising from neighboring bunches requires some care. • Transit time for high energy muon is ~8.5 ns through barrel calorimeter at 90º. • Hadronic showers create many long-lived neutrons and other decay particles. • Timing information available on hit basis. • Work needs to be done (or not) to develop effective strategies to handle this information.
tt Tracker Times 1500 ns Unweighted occupancy time (ns)
t vs p low momentum loopers
Single Electron SiD Cal Times 4.0 ns 5.0 ns
1.50 m Single Electron SiD Cal Times 4.2 ns 5.0 ns 1.25 m
time of energy deposition (ns) 5 10 4 10 3 10 2 10 1 10 0 10 0 20 40 60 80 100 120 140 160 180 200
Single Neutron SiD Cal Times 10,000 ns
LHEP QGSP_BERT QGSP QGSC Pion hadronic energy fraction vs calorimeter time (ns) 500 90% 480 460 440 420 400 Geant4 hadronic models 380 360 340 Time of flight to hadronic calorimeter 320 300 280 260 Fractional energy of a 90° 5 GeV pion in the hadron calorimeter deposited before time t. 240 220 200 180 ~6ns 160 140 120 100 80 60 40 20 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Pions Neutrons
Comments • Times in tracker can be handled (even for slow exotics) by adopting a follow-your-nose approach when adding hits to found tracks. • momentum allows t.o.f. to be estimated. • don’t consider hits outside expected time window. • Late-time calorimeter hits arising from hadronic showers are low-energy and diffuse around the shower core • These hits do not cluster. • Full timing information is available for more detailed studies (if necessary).
tt SiD Cal Times 269 ns
tt Cal Times 10,000 ns