1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Beta-Decay of Cs137

  1. Sep 28, 2012 #1
    I recently performed a Beta-decay experiment for a senior level lab course. I'm expected to write-up a report but I'm fairly confused as to some of the theory surrounding the Beta-decay of Cs137.

    This experiment deals solely with negative Beta decay, of which the predominant form (94%) is decay into the meta-stable Ba137, which theoretically has a 2.55 min half-life. This form undergoes internal conversion to Ba137. Only emmitted electrons are being detected by the sensor.

    When plotting electron count-rate vs Hall probe voltage (the set-up of this experiment entails the 180 degree deflection of emmitted electrons by way of a variable magnetic field-perpendicular to the movement plane), why is the distribution continuous?

    I have a plot consisting of two peaks (both of which I understand why exist-I think), however I don't understand why the count-rate outside these regions is not zero.

    Note that "background count" was accounted for, there was sufficient vacuum in the apparatus, and hysterisis (spelling?) was avoided.

    I apologize in advance if my description is vague; It would be unreasonable for me to outline the entire lab in a forum post.
  2. jcsd
  3. Sep 29, 2012 #2
    Anyone have any thoughts? I feel like I've really hit a wall here..

  4. Oct 2, 2012 #3
    Think about the way the detector "sees" an electron. That will tell you why the distribution is continuous.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook