PHYS 1407 – Conceptual Physics II

Detection of Radiation

 

Leader: _________________________          Recorder: __________________________

Skeptic: _________________________         Encourager: ________________________

 

Materials

Radiation detector

various exempt sources

stainless steel sheets

laptops for graphs

 

Procedure

1.  Turn on the radiation detector at your desk in audio mode.

 

Q1)  Do you observe any counts even if nor sources are nearby?

 

 

Q2)  Why might that be the case?

 

 

2.  Take the detector to each one of the exempt sources placed in the room.

D3)  Make a table in the space below recording the information listed about the sources and rate the relative count rates.

 

 

 

 

 

 

 

 

Q4)  Do some of the exempt sources seem to give higher count rates?

 

 

 

Q5)  The half life of the sources should be in your table above.  Keeping in mind that these sources have been around for a few years and started with approximately the same count rates, explain why some may have lower count rates than others now.

 

 

 

Safety

Uranium is a heavy metal and like all heavy metals is poisonous and attacks the central nervous system.  Handle the uraninite with gloves and wash your hands thoroughly after lab.

 

3.  Obtain a piece of uraninite and 5 stainless steel sheets.  Turn the detector on, but do not leave it in audio mode.

 

Place the piece of uraninite about 1 cm from the screen at the end of the detector.

D6)  Record the count rate in the first row of the table below.

 

Number of sheets

Count rate

0

 

 

 

 

 

 

 

 

 

 

 

 

D7)  Place 1 sheet between the piece of uraninite and the detector.  Wait several seconds for the count rate to adjust and then record the number of sheets and the count rate in the table.

 

D8)  Repeat D7)  for 2, 3,4 and 5 sheets.

 

D9)  Construct a properly labeled graph of count rate vs. number of sheets.  Print and attach the graph.

 

Q10)  Describe the graph.  Have you seen a graph similar to this one recently?

 

 

Q11)  Why is the count rate going down as the number oif sheets increases?

 

 

Q12)  Why do you think x-ray technicians where aprons made of lead when giving x-rays?