Single tube detection efficiencySingle tube detection efficiency BIS-MDTBIS-MDT

GARFIELD SimulationGARFIELD 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 SimulationGARFIELD Simulation

Longitudinal diffusion coefficient

Transverse diffusion coefficient

Drift VelocityDrift Velocity

Operation PrincipleOperation Principle

A muon with pT=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.

μμ

r

CVrE

1

2)(

0

0

rCV

rV ln2

)(0

0

Electronic SignalElectronic 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 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

ChamberChamber BIS-MDT 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 Time resolution of a system of a scintillatorsystem of a scintillator

++

smallsmall (15(1515151 cm1 cm33) ) reference scintillatorreference scintillator

Small contribution to Small contribution to the overall time the overall time

resolutionresolution

Hodoscope time resolutionHodoscope time resolution

BIS-MDT ‘BEATRICE’ atBIS-MDT ‘BEATRICE’ at the X5/GIF areathe X5/GIF area

Cosmic muons

Cosmic muons in presence of the background of the source Cs137 Photons 662 keV, 740

GBq (3/1997), t1/2=30 y

Photon flux at 4 m = 0,86105 cm-2s-1

ChamberChamber BIS-MDT BIS-MDT electronics 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 PrincipleMDT Operation Principle

Inefficiency due to a δ-δ-electronelectron 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 SpectrumEnergy Spectrum

MDT time spectrum MDT time spectrum

dx

dN

dt

dx

dx

dN

dt

dN

ConstantVelocity DependenceTDC Spectrum

ttmaxmax ttmaxmax

ttoottoo

tt11tt11