X-Ray Shielding

The purpose of this lab is to observe how shielding in lead aprons protect the body from radiation experimentally using a source of radiation and lead sheets.

PreLab Questions:

You all have been to the dentist and had an x-ray.  You likely had the dental technician put a lead apron over your chest to protect you.  Today we are going to determine if this is really needed.

1)What do you think the purpose of the lead apron is? 

     -I think that the purpose of the lead apron is to prevent the radiation particle from entering the parts of the your body that you don't want an X-Ray on to prevent unnecessary radiation from entering your body.

2) Before you start this lab, do you think the apron is needed or is it just to make you feel better?
    -I believe that the apron is definitely needed.

3) Why do you think they use lead inside the aprons?
    -I think they use lead inside the apron because the lead has a high density that prevents the radiation particles to travel through it.


Equipment:
-Logger Pro
-Source of radiation (¹³⁷Cs)
-Radiation detector
-Lead Sheets **I used aluminum foil instead**

Procedure:
Connect the LoggerPro equipment to the radiation detector and the computer.  Open the file "dental.cmbl" in LoggerPro to count the total number of radiation counts. Place the radiation source by the detector and record the total radiation counts in 60 seconds. Use the lead sheets of 0.2, 0.4, 0.8, and 1.0 mm as shield between the radiation source and the detector and record the number of radiation counts in 60 seconds. 

**Modifications:
There were no lead sheets available for this experiment. Instead, I used aluminum sheets. I measured 10 sheets of aluminum to be about 0.2 mm. I recorded the number of radiation counts using 10, 20, 30, and 40 sheets of aluminum foil. I cut 5 3x3 squares of aluminum foil and folded them in half to make 10 sheets of shielding. I then folded them to make 20. I cut another set of 5 sheets to fold for the 30 and 40 sheets of aluminum shielding. Also, there was no file named "dental.cmbl" in LoggerPro to count the total number of radiation counts, so I used a file called "04 Statistics" in the file named "_Nuclear Radiaiton w Vernier" to count the number of radiation counts per seconds. I totaled the number of radiation counts per second in 60 seconds to get the total radiation counts in 60 seconds. 

Data:

Post Lab Questions:
1) How does the Total Counts decrease as you increase the thickness of the lead?  Are you surprised by how much or little it changed?
      - The total counts decreased 26% within the first shielding and 16.5% from 20 to 30 sheets, 13.6% from 30 to 40 sheets. I did expect for the number of counts to decrease with increasing shielding. I did expect to see the biggest decrease in counts in the first shielding, but I didn't expect for the percentage to decrease as there was more radiation shielding. 

2)  The ¹³⁷Cs source we are using actually emits two kinds of radiation (gamma rays and beta particles).  The beta particles are completely stopped from entering the detector by 0.2mm of lead.  Does your data show this?  Explain.
     - I did not use lead sheets, but I did use aluminum foil. Beta particles are just electrons. Due to the fact that aluminum is a conductor of electrons, it is possible that some beta particles were stopped from entering the detector, but by researching online, it takes a couple millimeters of aluminum to completely block the beta particles. Therefore, the experiment does show that more particles are being blocked, which can mean that with increasing aluminum foil thickness, more beta particles are being blocked, but the gamma rays are still passing through the alumium foil.

3) What percentage did the counts decrease from the 0.2mm to 1.0mm tests?
     - There was a 36.8% decrease in the radiation counts from 10 to 40 sheets of aluminum foil which is the approximately 0.2mm to 0.8mm.


Conclusion:
This lab was meant for 4C students studying the different types of radiation. It was meant to be done with lead sheets to show how the beta rays are stopped by the high density of the lead. I think this experiment should be modified to observe alpha, beta, and gamma rays. It should be done with various amounts of "shields" to see the different types of materials (including lead sheets) that block the three types of radiation.