18/05/06P. Nedelec - 4th Air Fluorescence Workshop Measurements of FLY with MACFLY

2 Measurement of Air Cerenkov and Fluorescence Light Yield LAPP (France): Pierre COLIN, Patrick NEDELEC; LIP (Portugal): Antonio ONOFRE; JINR (Russia): Leonid TKATCHEV, Artem CHUKANOV, Basar SABIROV, Yuri NEFEDOV, Sergei POROKHOVOI, Dmitry NAUMOV. Collaboration:

3 Original Goals To Measure Air FLY variations as a function of atmospheric conditions: Reproduce and study in laboratory the light emitted by an “extensive air shower” (EAS) 15 km 2 km EAS Temperature Pressure Humidity - 60°C 10°C 100 hPa 800 hPa 0 % 1 % Altitude (km)

4 MACFLY project = 2 devices Vacuum pump N2N2 Air Ar O3O3 Beam: - β Source - CERN - JINR PMT Preshower Gauge : P,T,H 2 O H2OH2O shower Gas system MACFLY 1 (for beam) MACFLY 2 (for shower)

5 MF1: a reference device Single track events device –Light, compact, movable (plane?),… Used both Lab (quiet) –on Test Beam (noisy) Measure: –Air/N 2 FLY –Cherenkov contribution Used for comparison with –Other experiments –MF2

6 Macfly Laboratory Pompe à vide 90 Sr β Source PMT1 PMT2 Electrons beam Scintillator PM Trigger Radioactive source Sr90 Optic fibres Pressure sensor Main tank Temperature sensor Input/ouput of gas PMT Vacuum pump Trigger PMT

7 MF1 cut view EMI 9820Q A EMI 9820QA PMT EMI 9820QA Quartz Window Filters Quartz Lens Mirror : ~98% (multi-layers) Light Guide Electron beam 15 cm Macfly 1 optical system EMI 9820QA 5 cm Filter Filters Transmittance ( Schott BG3 and GG385)

8 MF2: looking for real showers A “From single track to showers” device –Heavy, Big, Fix,… Used: –Only on Test Beam Line Measure: –Air/N 2 FLY induced by a e - shower (10-50 GeV) –From 0 to X max radiation length Used to: –Perform original measurements –for comparison with Monte Carlo prg (G4,…)

9 Macfly 2 (MF2) Ø96 cm 146 cm Volume : ~1m 3 Input/Output of gas system CERN Beam PMT Sensors (P,T) Cooper target (Preshower)

10 MF2 working process EMI Black surface Ø10 cm Light guide Filters Preshower Electromagnetic Shower Preshower system: PMT EMI 9820QA Quartz Window Electron beam Stack of copper disks (Thickness :1cm) Lead shield

11 Measurement campaigns > At JINR ? : (MF1) –Microtron(12 MeV) and Phasotron (170 MeV) –Pressure and temperature dependencies > In Lab : (MF1) –Radioactive source (1.5 MeV electron) –Pressure dependence > At CERN : (MF1+MF2) –SPS test Beam (5-100 GeV e -, μ -, π - ) –Pressure dependence: ; Temp., H 2 O:  –Shower age dependence (MF2) Too noisy! Then a Fire !!!

12 MACFLY set up overview at CERN Macfly 2 Delay chamber MF2 Trigger MF1 Thermal Box Small Trigger MF1 in its thermal box Pumping system Large Trigger Delay chamber

13 Macfly Data Event by event acquisition PMT signal read by a QADC (Gate=100ns) Very Low signal: mean=0.01photoelectron Expected FLY ~ 4 ph/m ~10 6 triggers/run (1/2 data+1/2 Bgd)

14 Delay chamber MF2 Trigger MF1 Thermal Box Macfly Data selection Centered events

15 MacFly: Fluo. Signal extraction DL = FLY x ε MF + CDL + Bgd PMT Detected Light (fit method) Cherenkov Detected Light (Geant4 simulation) Background (Vacuum measurement) Fluorescence Light Yield (in photons) Detector efficiency (Calibration) FLY/E = FLY / E dep Deposed Energy (Geant4 Simulation)

16 Macfly Data Detected Light: PMT spectrum fit Method Pedestal : ( ~99% of events) Single photoelectron (~1% of event) 2 photoelectrons DL = FLY x ε MF + CDL + Bgd

17 MacFly: Geant4 Simulation Geometrical Acceptance (Optical Properties of surfaces were previously measured) ε MF = Acc geo x QE PMT DL = FLY x ε MF + CDL + Bgd

18 MacFly: Geant4 Simulation DL = FLY x ε MF + CDL + Bgd Cherenkov Light: compare simulation with data Lenses Cerenkov catcher e-e- Cherenkov light in MF1

19 MacFly: data Background: DL = FLY x ε MF + CDL + Bgd Well measured events –Random triggers –Off-spill triggers –Vacuum On-spill triggers

20 MacFly: Geant4 Simulation Radiation length (#X 0 ) 0 disc 1 disc 3 disc 5 disc 7 disc 10 disc Pre-Shower Deposed Energy in MF2 Deposed Energy: FLY/E = FLY / E dep

21 Detected Light Composition DL (Macfly data) CDL (Simulation) Bgd (Measurement) FDL Fluorescence detected light MF1 : 50 GeV e - in air MF1 : 50 GeV e - in N 2 MF1 : 1.5 MeV e - in air MF2 : 50GeV Shower in air

22 Systematic errors of MF1 Error Sources MF1 (Dry Air) CERNLab. QE of PMT10% Geo. Acc.8.2%7.5% DL Recon.3.5%4% CDL Simu.2%0% Bgd Meas.2%1% FLY :13.7%13.2% E dep 1% FLY/E :13.7%13.2%

23 MF1 result: Pressure dependence We create a model of air FLY proportional to deposed energy which fit all Macfly data. (Dry air and pure Nitrogen)

24 MF1 result: Energy dependence Reference point : Dry air at 1atm. & 23ºC: FLY/E = 18 ph/MeV dEdX: Berger-Seltzer formula All experiments are coherent

25 Absolute measurement Reference point : Dry air at 1atm. & 23ºC : FLY/E = 18 ph/MeV dEdX: Berger-Seltzer formula All experiments are coherent Error< 10% ?

26 MF2 result: Shower age dependence 500 hPa data 100 hPa data PDG model of shower development Air FLY follows the shower development !

27 MF2: Air FLY  deposed Energy FLY/E dep and pressure variations independent of the excitation source

28 Conclusion Measurements done: P. Colin thesis  Dry air and pure Nitrogen fluorescence  1.5 MeV, 20 GeV and 50 GeV incident electron  Lab. measurement of air Shower FLY  Pressure and Shower age dependencies Fluorescence model:  Air FLY  Edep  Fitted on Macfly data  Compatible with previous exp. (<10%) Back to the future:  PMT calibration  Temperature dependence  Papers in preparation Systematic down to: ~10%