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First Results from the MINOS Calibration Detector

First Results from the MINOS Calibration Detector. Patricia Vahle University of Texas at Austin for the MINOS Collaboration. Outline: MINOS in a Minute Why a 3 rd detector Detector & Beam Electrons & Hadrons Summary. Work made possible by: DOE, Welch—US PPARC—UK.

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First Results from the MINOS Calibration Detector

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  1. First Results from the MINOS Calibration Detector Patricia Vahle University of Texas at Austin for the MINOS Collaboration • Outline: • MINOS in a Minute • Why a 3rd detector • Detector & Beam • Electrons & Hadrons • Summary Work made possible by: DOE, Welch—US PPARC—UK

  2. MINOS in a Minute FarDetector (Soudan Mine) • 735 km long-baseline • neutrino experiment • Two tracking • calorimeters Near Detector (prototype) (Fermilab)

  3. Why a 3rd Detector? • Underground detectors-- • no calibration beam • 5%absolute calibration required • Calibration Detector (CalDet) to determine • response vs. • particle type (m, e, h) • energy • topology • TuneMonte Carlo • Tune pattern recognition algorithm-- • NC/CC separation • Characterize response in terms ofmuons • Study hadronic response of detector at • low energies

  4. The Detector Last Dipole T11 • 1 m x 1 m x 3.7 m • 60 planes of 1 cm co-extruded plastic • scintillator, backed by planes of 2.5 cm Fe • 5.9 cm pitch • 5 modules (for moving) • Each scintillator plane composed of 24 • strips, 4.1 cm wide, a total of 1440 strips • Consecutive scintillator planes rotated 90o • Wavelength shifting fiber glued into • scintillator routes light out of detector • Clear and green (to simulate size of far • detector) ribbon cable transports light • to PMTs Beam Line Electronics and PMTs 1m 24 strips x 60 (3.7 m) Scintillator 1m Steel 5.9 cm

  5. Active Detector Components • Near/Far Detectors differ • in readout to achieve • similar response. • CalDet directly compares • differences • Currently configured to • mimic Far Detector • Hamamatsu M16 • VA front-end • Double-ended readout • Future->mimic Near • Detector • Hamamatsu M64 • QIE front-end • reflectors

  6. Beam Line East Hall Schematic • T11 (East Hall) PS complex at CERN • Max p= 3.6 GeV/c • Dp/p=3% (collimators open) • Control of intensity • collimators • quad defocus • Beam composition: p, p, e , m  • PID: Cerenkov and TOF • Ran at energies ranging from 0.5-3.5 GeV, roughly 0.5 GeV steps Particle Fractions in T11 % Beam Momentum

  7. MINOS in a Beam • MINOS Far Detector electronics designed • for low rates • Rate Related effects in spill • Chips dead for 4.5 ms after readout • Hit channels take 50 ms to recover • Hence, at the CalDet, we write outevery hit! • Perform a plane trigger offline • Record “chip histories” e Energy MEU Channel Recovery after hit Dead Channels Strip Pedestal ADC Plane Time(ms)

  8. Particle Identification CER TOF • Threshold Cerenkov Detector for e identification • CO2 • pthresh,m=3.5 GeV, pthresh,p =4.5 GeV • Events from peak of pulse height distribution • Time of FlightSystem for p, p+ separation • 12.8 m lever arm • 35 psec. LSB • Other event selection criteria: • 4/5 plane trigger • electronics cuts • veto non-beam events • cuts on response in first scintillator plane

  9. Electrons and Positrons • MEU: Muon Energy Unit, mean pulse height due to a through-going muon measured in a strip end Hits “Wings” due to PMT xtalk Strip Plane Sample Event (2GeV e+) Strip vs. Plane profile, weighted by number of hits Even Plane view Odd Plane view MEU Relative Pulse Height Strip Strip Plane Plane Strip vs. Plane profile, weighted by MEU deposited

  10. Electron Event Characteristics MEU(plane)/Tot. MEU vs. Plane number X0=4.1 cm (.69 planes) <Planes Hit>=10.3 MEU(strip)/Tot MEU vs. Radius rm=3.1 cm (.75 strips) MEU MEU Distribution Sigma/Mean = 16.5%

  11. Detector Response Total MEU vs. Beam Momentum MEU=p1*Momentum+p0 Total MEU Preliminary Resolution2 vs. 1/Beam Momentum Momentum Res2=k2+m2/p Resolution2 Expected resolution, 23%/E constant term <5% 1/Momentum

  12. Hadrons Sample Pion Events Sample Proton Events Odd Plane view Even Plane view Even Plane view Odd Plane view Strip Strip Relative Pulse Height Relative Pulse Height 3.5 GeV 3.5 GeV Plane Plane 2 GeV 2 GeV 1 GeV 1 GeV

  13. Hadron Event Characteristics Pions (+1.6 GeV) Protons (+1.6 GeV) Peak at ~38 hits/event Peak at ~50 hits/event Peak at ~13 Planes Hit Peak at ~13 Planes Hit

  14. Energy Spectra of Hadrons Pion MEU distributions Proton MEU Distributions 1 GeV 1.6 GeV 1.6 GeV 1 GeV 2.5 GeV 2 GeV 2 GeV 2.5 GeV 3 GeV 3.5 GeV 3 GeV 3.5 GeV

  15. Summary • CalDet Preliminary results: • EM resolution 23%, as expected • Analysis of hadrons progressing • Further analysis • Tune MC • Pattern Recognition • More data in 2002-2003 • Higher energies • Different electronics

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