Aei405
This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA
Overview
Download & View Aei405 as PDF for free.
More details
- Words: 601
- Pages: 19
DEPARTMENT OF TECHNICAL EDUCATION ANDHRA PRADESH Name Designation Branch Institution Year/sem Subject Subject code Topic Sub topic Duration Teaching Aids
: M. Vani : Lecturer : AEIE : Dr. B. R. Ambedkar. GMRP,KNR : IV-SEM : Process Instrumentation-II : AEI-405 : Nuclear Instrumentation : GM tube : 50 minutes : Visuals, Diagrams AEI-405.79 to 80
1
Recap In previous topic we have discussed about : • Neutrons • Appearance of neutrons • Detection of neutrons
AEI-405.79 to 80
2
Objectives Upon completion of this topic you would be able to know about • Geiger Muller method for detection of
nuclear
radiations
AEI-405.79 to 80
3
Description of Geiger Muller Tube • It is used for detection & measurement of • Alpha rays • Beta rays • Gamma rays • This is a diode consisting of a cathode and anode • Cathode is a long metal cylinder. • The anode is a fine wire running through the center of the cylinder. AEI-405.79 to 80
4
Geiger Muller Tube
AEI-405.79 to 80
5
GM tube animation
AEI-405.79 to 80
6
GM TUBE
AEI-405.79 to 80
7
Description… • The anode and cathode are mounted in thin walls, air tight, glass envelope, sealed by extremely thin • The radiations can pass through this window. • The voltage of the battery is kept below the ionization potential of the gas. • The radiation penetrates through the window and enters the envelope and ionizes some of the gas atoms.
AEI-405.79 to 80
8
Description… • The resulting -ve ions go towards the anode and +ve ions go towards cathode. • The ions collide with some of the gas atoms to ionize in their passage. • This process continues till whole of the gas atoms are ionized.
AEI-405.79 to 80
9
Description… • The complete ionization takes place in no time • A pulse of current flows through the tube. • This current flows through the resistance ‘R’ which is connected to in the anode circuit • The resulting voltage drop across ‘R’ is the output voltage. AEI-405.79 to 80
10
Description… • Once ionization is started it is expected to continue indefinitely • When the gas ionizes a heavy current flows through large resistance R • It causes a large voltage drop • This voltage drop is sufficent to reduce the anode voltage below the ionization potential AEI-405.79 to 80
11
Description… • Therefore, ionization ceases • As long as gas is not ionized no current flows through the resistance R and hence there is no output • Now if a radiation again enters the tube the ionization starts and a current again flows through the resistor R giving an output voltage
AEI-405.79 to 80
12
Description… • Thus the series of alpha, beta, or gamma rays cause current pulses to pass through the anode circuit. • The output pulses at ‘R’ may be amplified and the pulses are counted. • By counting the no.of pulses we can know the number of particles entering the geiger muller tube in a particular interval of time • The counting rate of this tube is greater than 103 counts/sec
AEI-405.79 to 80
13
Geiger Muller tube
AEI-405.79 to 80
14
AEI-405.79 to 80
15
Summary In this topic we have learnt about : Descrption of G-M tube
AEI-405.79 to 80
16
Quiz 1.
To detect the nuclear radiations --------is used a) Pulse detector b) Particle detector c) Geiger Muller tube d) None
AEI-405.79 to 80
17
Frequently asked questions
1.
Draw and explain about the Geiger Muller tube.
AEI-405.79 to 80
18
Thank you
AEI-405.79 to 80
19
: M. Vani : Lecturer : AEIE : Dr. B. R. Ambedkar. GMRP,KNR : IV-SEM : Process Instrumentation-II : AEI-405 : Nuclear Instrumentation : GM tube : 50 minutes : Visuals, Diagrams AEI-405.79 to 80
1
Recap In previous topic we have discussed about : • Neutrons • Appearance of neutrons • Detection of neutrons
AEI-405.79 to 80
2
Objectives Upon completion of this topic you would be able to know about • Geiger Muller method for detection of
nuclear
radiations
AEI-405.79 to 80
3
Description of Geiger Muller Tube • It is used for detection & measurement of • Alpha rays • Beta rays • Gamma rays • This is a diode consisting of a cathode and anode • Cathode is a long metal cylinder. • The anode is a fine wire running through the center of the cylinder. AEI-405.79 to 80
4
Geiger Muller Tube
AEI-405.79 to 80
5
GM tube animation
AEI-405.79 to 80
6
GM TUBE
AEI-405.79 to 80
7
Description… • The anode and cathode are mounted in thin walls, air tight, glass envelope, sealed by extremely thin • The radiations can pass through this window. • The voltage of the battery is kept below the ionization potential of the gas. • The radiation penetrates through the window and enters the envelope and ionizes some of the gas atoms.
AEI-405.79 to 80
8
Description… • The resulting -ve ions go towards the anode and +ve ions go towards cathode. • The ions collide with some of the gas atoms to ionize in their passage. • This process continues till whole of the gas atoms are ionized.
AEI-405.79 to 80
9
Description… • The complete ionization takes place in no time • A pulse of current flows through the tube. • This current flows through the resistance ‘R’ which is connected to in the anode circuit • The resulting voltage drop across ‘R’ is the output voltage. AEI-405.79 to 80
10
Description… • Once ionization is started it is expected to continue indefinitely • When the gas ionizes a heavy current flows through large resistance R • It causes a large voltage drop • This voltage drop is sufficent to reduce the anode voltage below the ionization potential AEI-405.79 to 80
11
Description… • Therefore, ionization ceases • As long as gas is not ionized no current flows through the resistance R and hence there is no output • Now if a radiation again enters the tube the ionization starts and a current again flows through the resistor R giving an output voltage
AEI-405.79 to 80
12
Description… • Thus the series of alpha, beta, or gamma rays cause current pulses to pass through the anode circuit. • The output pulses at ‘R’ may be amplified and the pulses are counted. • By counting the no.of pulses we can know the number of particles entering the geiger muller tube in a particular interval of time • The counting rate of this tube is greater than 103 counts/sec
AEI-405.79 to 80
13
Geiger Muller tube
AEI-405.79 to 80
14
AEI-405.79 to 80
15
Summary In this topic we have learnt about : Descrption of G-M tube
AEI-405.79 to 80
16
Quiz 1.
To detect the nuclear radiations --------is used a) Pulse detector b) Particle detector c) Geiger Muller tube d) None
AEI-405.79 to 80
17
Frequently asked questions
1.
Draw and explain about the Geiger Muller tube.
AEI-405.79 to 80
18
Thank you
AEI-405.79 to 80
19
