Single tube detection efficiency BIS-MDT

GARFIELD Simulation GARFIELD Simulation Anode wire voltage as a function of the distance from the wire Electric field as a function of the drift path Muon track in a distance of 0.1 cm from the anode wire

Electron drift velocity (in cm/μsec) as a function of the drift path Ion mobility as a function of the electric field Diffusion coefficients (transverse and longitudinal) as a function of the electric field GARFIELD Simulation Longitudinal diffusion coefficient Transverse diffusion coefficient

Drift Velocity

Operation Principle A muon with p T =1ΤeV/c has a track sag τροχιά of  500 μm in a magnetic field 0.4 Τ (mean value). Momentum resolution of 10  requires precision of 50 μm in the muon track sag. μ

Electronic Signal PM Analog Signal Amplitude 400 mV Time Width 20 ns PM Logic Signal  Preamplifier  Discriminator (constant fraction) Amplitude 600 mV Time Width 14 ns

Hodoscope Logic Diagram Meantimer : Time resolution 1 ns TDC: Time resolution 50 ps on 100 ns range System time resolution 1,5-2,0 ns Spatial resolution 20 cm

Chamber BIS-MDT Gas Manifold Parallel gas supply at each tube at each multilayer Hedgehog cards Decouple the signals from the wires and provide discharge protection for the amplifier inputs Mezzanine cards 4 Amplifier Shaper Discriminator chips 1 TDC chip

Time resolution of a system of a scintillator + small (15  15  1 cm 3 ) reference scintillator Small contribution to the overall time resolution Hodoscope time resolution

BIS-MDT ‘BEATRICE’ at the X5/GIF area Cosmic muons Cosmic muons in presence of the background of the source Cs 137 Photons 662 keV, 740 GBq (3/1997), t 1/2 =30 y Photon flux at 4 m = 0,86  10 5 cm -2 s -1

Chamber BIS-MDT electronics Pseudo-differential pair of preamplifiers (Active and Dummy) Differential amplifier (gain) – Two stages of Differential Amplifiers (gain & bipolar shaping) Shaper Discriminator ADC (leading edge slew correction timing resolution)

MDT Operation Principle δ-electron Inefficiency due to a δ-electron shadowing the muon. Probability  Distance Discreteness of the ionization mechanism Lower resolution close to the wire Decrement of the track-wire distance Large fluctuations

Energy Spectrum

MDT time spectrum MDT time spectrum Constant Velocity Dependence TDC Spectrum t max totototo totototo t1t1t1t1 t1t1t1t1