Characterization And Testing Of

2m X 2mGlass Resistive Plate Chamber

Mohammed Salim M

Aligarh Muslim University

Topics

Introduction Principles of Operation Gas Mixture Fabrication Testing Trigger Results

Introduction

INO (India based Neutrino Experiment) is India’s biggest experiment to study the properties of weakly interacting, electrically neutral fundamental particle, neutrinos

Underground experiment will study the properties of ‘Atmospheric Neutrinos’.

Resistive Plate Chambers (RPC) are the active detectors used in the proposed INOICAL (Iron Calorimeter)

Introduction (contd..)

Introduction (contd..)

Two 3mm thick float glassesSeparated by 2mm spacers

2mm thick spacer

Glass plates

Graphite coating on the outer surfaces of glasses

Pickup strips

Various layers of RPC

Principle of operation

3

Two modes of operation

o Avalanche mode

o Streamer mode

l

A

A

lRC

s 2)10 x (8.85 x 4 x )10 x ( -1210

Gas mixture

The gas mixture fixes the working mode of RPC

Three gases are used in avalanche mode

R134A( as Freon) 95.4% Isobutane 4.3% SF6 0.3%

Avalanche and Streamer pulses Taken from CRO

Fabrication

1. Glass cutting and cleaning2. Conductive coating3. Gas leak test4. Connecting High Voltage Cables5. Placing pick up panels6. Connecting Pre Amplifier boards

Surface resistance measurement

1 div~33cm

Uniform surface resistance of 1 MΩ is expected.

VI Characteristics

Trigger

• Scintillator paddles are used for triggering the RPC pulse

Block diagram of lab set up

Results of 2m X 2m RPC

Efficiency Noise rate at various voltages

Fixed operating voltage at 9.6 kV

Effect of SF6

TDC and QDC plots

TDC plot of the main strip (strip no.32) ADC plot of the main strip

Calibration of the MFC

The gas is fluxed into the tube and then water is allowed to flow through the tube. The gas apply the pressure on the water and water bubble flows through the tube and we can determine the rate of flow by measuring the change in volume in some fixed time with the help of stop watch.

Water flow

Glass tube Gas flow

Scale

Calibration plots of MFC

Calibration plots of MFC

Snap shots from our work shop

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