Geiger muller counter

Presentation Geiger Muller Counter

1. Geiger Muller Counter Presented to: Respected Dr. Kamran Sb. Presented by: Tahir Younus Roll No. BS-PHYS-18- 44 Course: BS Physics 5 th (E) Department of Physics Ghazi University DG Khan

2. Outline Introduction 1 History 2 Basic Components 3 Diagram 4 Principle and Working 5 Efficiency 6 Applications 6

3. The Geiger Counter is an instrument used for measuring ionizing radiation. It detects ionization radiations such as α-particles, β- particles and γ-rays using the ionization effect produced in a Geiger-Müller tube. It is perhaps one of the world’s best-known radiation detecting instrument. Introduction

4. In 1908,the first model of G.M. Counter was developed by Hans Geiger and Ernest Rutherford which was only capable of detecting α-particles. In1928, Geiger and Walther Muller developed advanced model of Geiger M uller Counter consisting of sealed G.M. Tube capable of detecting all kinds of radiations. Interesting fact is that it was developed under- supervision of Hans Geiger by Walther Muller who, was PhD student of Sir Hans Geiger. History

5. Basic Components A Geiger counter consists of a Geiger-Müller tube, the sensing element which detects the radiation, and the processing electronics, which displays the result. The Geiger-Müller tube is filled with an inert gas such as helium, neon, or argon at low pressure, to which a high voltage typically 400- 600 V is applied.

6. Schematic Diagram

7. Geiger Muller Counter

8. Principle & 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 tube acts as cathode.

9. 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 comes out of atom, the remaining atom is positively charged. Due to the high voltage in tube, it produces electric field. The electrons that come 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.

10. Efficiency of Geiger Muller Counter  

11. Precautions While Operating If the continuous discharge is produced, the voltage should be lowered. The applied voltage must be relatively stabilized. Introduction of light should be prevented to avoid photo electric effect.

12. Applications To detect radioactive rocks and minerals in the course of mineral prospecting. To check for radioactive contamination of clothing and shoes in your workplace. To check possible leakage or exposure to X-rays in a medical facility. To check for radiation in areas where depleted uranium ammunition shells have been used.

13. To check for irradiated gemstones in the jewellery trade. To check the levels of iodine 131 in cancer patients undergoing radiation therapy. You are in close proximity to a uranium mine and want to test the soil and environment for dangerous levels of radioactivity. To test for radioactive contamination of food. To check materials in your anthropology or archaeology field. Applications

14. To check for radioactivity in metal objects in your home or office that could be made of recycled radioactive materials. Applications