Radiation Detection Experiment

Introduction to the Radiation Detection Experiment

Radiation Detector is an instrument used to detect or identify high-energy particles, such as those produced by nuclear decay, cosmic radiation, or reactions in a particle accelerator. an example of radioactivity measuring devices is (Geiger- Muller counter ( GM )) is a simple device which is used using for measuring radioactivity.

Aim Of The Radiation Detection Experiment

-To distinguish among alpha, beta and gamma radiation.

-To verify inverse square relationship between the distance and the intensity.

Tools Of The Radiation Detection Experiment

The radiation detector (Geiger- Muller counter (GM) is a simple device which is used using for measuring radioactivity. It consists of a metal tube called cathode, containing inert gas at low pressure and a wire along its central axis called anode. One of the end tube usually has a very thin window made of some low-atomic mass material, such as mica or beryllium, through which radiation can easily enter. When the ionizing radiation enters to the GM tube. It is ionizing the inner gas and producing ions and free electrons. The flow of charge causes a pulse current and this current amplified and detected by external counter
Radioactive sources are (Ɣ-source Co-60) and (Cs-137), α source (Am-241), β- sources (Ti-204) and Sr-90).
Also, the sheets of aluminum and lead used in this experiment.

Steps And Method Of The Radiation Detection Experiment

1- Distinguish among alpha, beta and gamma radiation -Take one radioactive source and set it on the holder. -Set GM-tube in front of the source. -Set up the source at fixed distance (10 cm) from GM-tube. -Turn on the counter. -Place sheet of paper between the source and the GM-tube, regard the counter if not stop use thin sheet of aluminum and regard the counter if not stop then use sheet of lead. -Explain the results.
2-Verify inverse square relationship between the distance and the intensity -Determine the background count by measuring number of particles entering the tube without source. Background radiation comes from cosmic ray, natural radioactive material in rocks, soil and in bricks of building.
-Take radioactive source e.g. beta source and set it on the holder.
-Set GM-tube in front of the source.
-Place the source at distance (1 cm) away from the tube. -Turn on the counter set the counting time at 60sec.
-Record the count rate. -Repeat step 6 with distance 2, 3,4,….,10 . -Tabulate the results
-Plot the graph between square distance and actual intensity.

Table of The Readings For The Radiation Detection Experiment

Background count-rate r₀ = ……… min⁻¹

Absorber thickness x/cm	Count-rate r/min⁻¹	Log R/min⁻¹
0
1
2
3

Medical Application Of The Radiation Detection Experiment

Alpha particles:-
1-To treat various form of cancer by inserting tiny amount of α –particles into cancerous mass, such as brain tumor, pancreatic, ovarian and melanoma cancers. 2- α-particles are used for treating bone cancers. 3-Treating leukemia: which may involve bone marrow transplant by kill the defective bone marrow by lethal dose of radiation before being replaced with healthy bone marrow.
Beta particles:- 1-To treat thyroid disorder by using Iodine 131. 2-Treating eye disease. 3-Treating skin cancer.
Gamma rays:- 1-Gamma photons are used in treating cancer by irradiating cells that need to be kill. 2-It is used in diagnoses by using radioisotopes emitter ɣ rays off sufficient energy to escape from the body and it have short half-life to decay away soon after imaging is completed. 3-It is used in sterilizing medical products such as syringes, gloves, clothing and instruments.

Frequently Asked Questions About the Radiation Detection Experiment

Why does paper stop alpha particles but not beta or gamma radiation?

Alpha particles are relatively large and heavily charged, so they lose their energy quickly and are stopped by even a thin barrier like paper. Beta particles need a denser shield like aluminum, while gamma rays require thick lead to significantly reduce their intensity.

Why is background radiation measured before testing a radioactive source?

Cosmic rays and naturally occurring radioactive material in soil, rocks, and building materials constantly produce a small baseline count. Subtracting this background rate ensures the measured count reflects only radiation from the source being tested.

Why does radiation intensity follow an inverse square relationship with distance?

As radiation spreads out from a point source, it disperses over an increasingly larger spherical area, so the intensity at any given point falls off proportionally to the square of the distance from the source.