LAB EXERCISE #1: DETERMINATION OF BACKGROUND RADIATION

       We live in a radioactive environment. The food you eat, the air you breathe, the ground you walk on, the water you drink, and the house you live in all contain radioactive isotopes. This radiation that is constantly present in our environment is called Background Radiation. The majority of background radiation comes from three major sources: radiation from the sun and outer space, radiation from radioisotopes produced in the atmosphere and radiation from the earth itself in the form of the radioactive elements that have always been here. Consequently before experimentally measuring any material to determine its level of activity radioactivity you must determine the existing background radiation and subtract this from any subsequent readings.

Select safety precautions:
       In order to complete any of the laboratory exercises you will first be required to select appropriate safety precautions. Select from the list below all safety precautions required before starting any of the laboratory experiments. Incorrect selection and/or insufficient numbers of the appropriate safety requirements will prevent you from continuing on with this program. Using the mouse click on only those required.

Required safety precautions:

Safety Goggles
Gloves
Ear Protection
Lab coat or apron
Appropriate labeled waste containers
Detection Instrumentation
Steel-toed Safety Shoes


Instrumental Procedures:
  1. Turn on the Scaler/Timer with G-M tube.
  2. Timer interval switch is preset for one minute readings.
  3. Record the background activity for at least five, 1 minute counts. Increasing the number readings will increase the accuracy of the count rate.
  4. The readings must be made in a continuous series without interruption, and the counter and other conditions must not be disturbed throughout the readings. Each reading in counts per minute (cpm) should be recorded in your data table .
  5. Average your readings to obtain a mean value in cpm for the background activity. Show the calculation and record this mean value appropriately in your lab notebook.
  6. Remember that the mean (average) background activity must be subtracted from all subsequent activity readings observed in the remaining experiments.

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