Experiment 18
THE EFFECT OF DISTANCE ON INTENSITY OF RADIATION

PROCEDURE


♦♦♦ DO NOT UNDER ANY CIRCUMSTANCES ATTEMPT TO MEASURE THE GM TUBE DIRECTLY. ♦♦♦


1.  Open the Worksheet and fill in the header information.

2.  Set the operating voltage on the scaler as in previous experiments, that is, at a level of 80 volts above the minimum voltage where counting just begins.

3.  Record the type of source that will be used in cell D10. Place the source on tray level #1 and take a 5 minute count. Enter the value in the first row of the Table in cells D18:D23.

4.  Move the source to levels #2 through #6 successively. Each time record the number of counts for 5 minutes in the successive rows of the Table.

5.  Measure the distance in centimeters from the detector to levels #1 through #6, and record the values in the Table at cells E18:E23. Do this at the edge of the tray holder.