Introduction to Geiger Counter:
The Geiger-Mueller tube is the main part of the Geiger counter apparatus which is used in this experiment. The radioactive source for the experiment is Cesium-137.
Hans Geiger, along with Rutherford identify the nucleus after whom the tube is referred to as a GM tube. The tube is in the shape of a cylinder about 1 cm in diameter and about 4 cm long. We carry the Cesium-137 source close to the end of the Geiger-Mueller tube.
The main features of the source:
- The half-life for the cesium-137 decay is 30.2 years
- The source activity was 5 micro Curies when new (1 Curie = 3.7 x1010decays per second)
- The energy of the emitted gamma rays is 661.6 K eV (1 KeV = 1 thousand electron-volts).
Geiger counter Viva Questions
Some Viva questions are listed here related to the Geiger counter:
- What interval did you select to note the counts?
- What is the minimum number of counts detected in that interval?
- Cesium-137 decays into Barium or Uranium?
- When Cesium-137 decays, which particles eject?
- From which excited nuclei photon emits, the Cesium-137 or Barium-137?
- Why should you clean the hand after performing the experiment?
- What precaution you should keep when performing the Geiger-Mueller experiment?
Questions working of Geiger-Muller Tube
- In which region the GM TUBE cannot distinguish between different type of radiations and why?
- A metal wire that is stretched at the axis of the cylinder (GM TUBE) is Anode or Cathode?
- This tube is filled by what type of gas and some volatile compounds?
- The potential difference between the anode and cathode of the tube is of what order?
- What type of particles this detector can detect?
- Can we detect the counts of radiation without the ionization inside the tube?
- Does the cylindrical geometry of the tube play any role to define the electric field in the tube? If yes, where it will be maximum?
Part -2 of working
- The Townsend avalanche created due to the high electric field, where it takes place?
- For the second avalanche which particle is responsible within the G M TUBE?
- What is Geiger’s discharge?
- What do you understand from photo-electron in the tube and how they emit?
- Does photo-electron initiate the second avalanche?
- In the G M TUBE does every avalanche initiate the next avalanche, if yes what is the main point behind it?
- From mass points of view, at a constant potential difference does two different massive particles will move at the same speed?
- A space charge produces near to the central wire during the avalanche process, is this space charge created by the electrons or by the positive ions?
- The Geiger discharge repeated at fix interval of time, what is the reason for it?
- What is the concept of voltage drop, and how it helps to detect the rate of ionizing radiation?
- What do you mean by the characteristic curve for the counter? What it reflects?
If you want to know more about the Geiger-Muller tube and its working, let me know. You can write your question in the comment box below.