Detecting Radiation Flashcards
All 5 cards in this deck
What are the two methods for detecting and measuring radioactivity you must know?
Photographic film and a Geiger–Müller (GM) tube.
How does photographic film detect radiation?
The film becomes darker (fogged) the more radiation it absorbs.
What does a Geiger–Müller tube connected to a counter measure?
The count rate – the number of counts (clicks) detected per second.
What are the steps to measure the count rate of a source using a GM tube?
e.g. background is 20 counts/min, tube with source reads 320 counts/min
- Measure the count rate with no source present: 20 counts/min.
- Measure the count rate with the source in place: 320 counts/min.
- Subtract the background: counts/min from the source.
True or false? Photographic film shows the total radiation received over a period of time rather than an instant reading.
True. A GM tube gives an immediate count rate; film records a cumulative dose.