Gm counter

GM counter in the environmental

1. KUVEMPU UNIVERSITY JNANASAHYADRI SHANKARAGHATTA SEMINOR ON G-M COUNTER GUIDED BY KRISHNA KULKARNI LECTURER DEPT.OF ENVIRONMENTAL SCIENCE PRESENTED BY DASTAGEER. A 1 ST YEAR M.SC ENVIRONMENTAL SCIENCE

2. INTRODUCTION Geiger-Muller counter was invented by H.Geiger and E.W. Muller in 1928. It is also called as G-M counter. The G-M counter is device used for the detection and measurement of all types of radiations, such as alpha, beta and gamma radiations.

3. CONSTRUCTION OF G.M COUNTER. G.M counter is a cylindrical tube with a wire at the center consists of a pair of electrodes surrounded by a gas. The electrodes have a high voltage across them. The gas used in the tube is Helium or Argon.

4. Schematic diagram of a G.M counter-Wikipedia

5. PRINCIPLE AND WORKING All the nuclear radiations such as alpha, beta and gamma radiation will ionize while passing through a gaseous medium. This ionizing property of nuclear radiations is used for the detection. In the GM counter the central wire acts as anode and the acts as cathode.

6. When an ionizing radiation such as alpha, beta, gamma radiation enters the tube it ionizes some of the gas molecules in tube. From these ionized atoms an electron is comes out of atom, the remaining atom is positively charged. Due to the high voltage in tube, it produces electric field. The electron that comes out of atom are attracted to positive electrode and positively charged atoms are attracted to negative electrode. This produces a pulse of current in wires connected to electrodes and the pulse is counted.

7. Efficiency of G.M counter: E= No. of particles of radiation detected No. of particles of radiation emitted

8. ADVANTAGES: They are relatively inexpensive. They can detect all types of radiation DISADVANTAGES: They cannot determine the exact energy of detected radiation. They have a very low efficiency.

9. CONCLUSION Geiger muller counter are regarded as one of the best radiation detection instruments and is used widely and prominently. Geiger muller counters are used in numerous fields and it is regarded as best tool for detection and measurement if ionizing radiation.

10. Thank you