What Is A GM Counter?
A Geiger counter also referred to as Geiger-Muller tube is used for detecting and measuring all kinds of radiation including Alpha, Beta and Gamma. The device includes a counter, tube and power supply. The tube is usually cylindrical with wire across the center. The power supply and counter have voltage control and power options.
It is also composed of a pair of electrodes enclosed by argon or helium gas. The radiation entering the tube ionizes the gas. There is usually existence of high voltage between the electrodes. When electrons and ions are attached to the electrodes, an electric current is produced. The current pulses are counted by a scaler and a count is obtained whenever the gas is ionized by radiations.
Types Of GM Counters
- Particle counters for measuring Alpha, Beta and H particles
- Gamma-ray counters for measurement of X-ray, cosmic and gamma rays.
- Photoelectric quantum computers that use features of photo-cells and counters. These are used to quantify weak ultraviolet light.
What Is A scintillation Counter?
A scintillation counter is a radiation detector instrument that is used to measure ionizing radiation. A scintillation counter is made up of a sensitive photodetector (usually a photomultiplier tube), a charge-coupled device camera (CCD) which converts light to electric signal and a scintillator which generates photons in response to incident radiation.
Scintillation counters have a wide application in radiation protection, physics research and assay of radioactive materials because they have good quantum efficiency and can measure both the energy and intensity of incident radiation.
Also Read: Difference between scintillation counter and proportional Counter
Difference In Tabular Form
| BASIS OF COMPARISON | GM COUNTER | SCINTILLATION COUNTER |
| Sensitivity | GM counters are less sensitive and cannot detect minute quantities of radiation. | Sensitivity of scintillation counters is very high and can effectively detect minute quantities of radiation. |
| Cost | The cost and maintenance of GM counter devices is very low. | The cost and maintenance of Scintillation counter devices is very high. |
| Instrument Size | The size of the GM counter device is relatively smaller than that of scintillation counter. | The size of scintillation counter device is relatively larger than that of GM counter. |
| Working Principle | The working of GM counters is based on the principal of individual gas ionization. | The working of scintillation counters is based on the principle of scintillation of crystals. |
| Number Of Electrodes | Two electrodes are used to produce secondary electrons in GM counters. | In scintillation counters, a multiple number of electrodes are used to produce secondary electrons. |
| Sensitivity To y rays | GM counter is less sensitive to y radiations. | A scintillation counter is very much efficient and sensitive to y radiations |
| Ionization Products | When gas molecules get ionized in GM counters, both ions and electrons are produced. | In scintillation counter, no ions are produced; it is only electrons that are produced. |
| Voltage Requirement | GM counter requires relatively low voltage to work efficiently. | Scintillation counter requires relatively high voltage to work efficiently. |
Application of Scintillation Counters
- In vivo and ELISA alternative technologies
- Protein interaction and detection
- Screening technologies
- Radioactive contamination
- Nuclear power and environmental applications
- Pharmaceutical
- Academic research such as Cellular research, epigenetics and cancer research