PPT-SEMINAR PRESENTATION ON GM COUNTER

1. *
PRESENTED BY-
TOPIC : GEIGER MULLER
COUNTER
ARJUN K K
3rd BSc PHYSICS
ROLL NO : 4505
CKGM GOVT COLLEGE PERAMBRA
CALICUT

2. 
G M COUNTER

3. INDRODUCTION
 G M COUNTER- GEIGER MULLER COUNTER
 G M COUNTER IS AN INSTRUMENT USED FOR MEASURING IONIZING -
RADIATION
 IT DETECTS IONIZING RADIATION SUCH AS ALPHA PARTICLES,BETA
PARTICLS AND GAMMA RADIATION USING THE IONISATION EFECT
PRODUCED IN THE G M TUBE

4. PRINCIPLE
O GAS MOLECULES GETS IONIZED WHEN ENERGETIC
PARTICLES CHARGED PARTICLE PROPAGATES THROUGH
A GAS
O THE ELECTRONS PRODUED BY IONIZATION , IF
ACCELARATED BY A POTENTIAL CAN CAUSE FURTHER
IONIZATION OF PARTICLES,THEREBY GENERATING A
LARGE NO.OF MORE ELECTRONS

6.  IT CONSIST OF A HOLLOW CYLENDICAL GAS TUBE(G M
TUBE)
 GM TUBE IS FILLED WITH INERTGAS (GENERALY
ARGON)+VAPOUR OF ETHYL ALCAHOL
 GM TUBE IS ENLOSED IN PARTIALLY EVACUATD GLASS
TUBE
 A TUNGSTEN WIRE OF 0.5mm DIAMETER IS FIXED ALONG
WITH THE AXIS OF GM TUBE
 TUNGSTEN WIRE CONNCTED TO +VE TERMINAL
 METAL GM TUBE IS CONNECTED TO –VE TERMINAL OF
HIGH TENSION BATTERY

7. WORKING
 WHEN AN ENERGTIC PARTICLE ENTERS GM TUBE
THROUGH THE WINDOW , THE GAS MOLECULE
WHICH INTERACT WITH CHARGED PARTICLE
GET IONIZED

8.  THE GENERATED ELECTRON GET ACCELARATED TOWARDS THE
CENTRAL ANODE AND +VE IONES TOWARDS CATHODE
 THE ACCELARATED ELECTRON CAUSE IONIATION OF MORE
GAS MOLECULES
 GENERATING A LARGE NO.OF ELECTRONS FROM A SMALL
INTERVAL OF TIME IS CALLED AVALANCHE
 THE AVALANCHE GIVES RISE TO HIGH CURRENT PULSE
 FOR EACH PARTICLE ENTER IN TO THE TUBE SUCCESSIVE
CURRENT PULSES ARE PRODUSED AND COUNTING IS DONE
BY A SUITABLE DEVICE

9. THANKS