Halflife Measurements
In a previous semester, you may have used LabVIEW to measure the half-life of a simulated radioactive source. This experiment is a continuation of that work. Instead of a simulated source, though, you will use actual sources and detectors. The sources available are neutron-activated Indium, neutron-activated Silver, and Barium-137M from Cesium-137 decay. The detector you use is up to you; options include various Geiger counters, NaI scintillation counters, and even an HPGe detector if you plan ahead to ensure that liquid nitrogen is available for it.
Equipment for this experiment works reliably, but there are some sneaky hidden challenges in the analysis.
Reading
- Here is an experiment manual from a different class that describes the experiment.
- There is a chart of the nuclides outside room 123. Learn how to read it.
Questions
- List advantages and disadvantages for each of the detectors available. Which will you use, and why?
- Some of your samples will have quite low activity. Explain how you intend to manage the challenge of measuring low half-life under these conditions.
- What would the results look like, and how would you analyze the data, if your sample contained multiple radioactive isotopes?
Location
Room 107.
Equipment needed
- Oscilloscope
- Detector of choice with appropriate electronics: Geiger tube, NaI, HPGe
- National Instruments ELVIS II board or other interface with at least a 16-bit counter
- Radioactive sources
Cautions
- High voltages exist on all detector options listed. These voltages are shielded if connected properly and are thus not a hazard unless you do something stupid.
- One lab student must wear a dosimentry badge in the lab at all times while this experiment is in use.
- The HV should be the last thing you turn on, and the first thing you turn off.