Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How to set the threshold of a discriminator? (Lab)

  1. Feb 10, 2009 #1
    I'm doing a lab to find the lifetime of the muon. In calibrating the equipment I need to set the threshold voltage of the discriminator to limit noise from producing digital pulses. My writeup is terribly written and I can't find an explained procedure online. My prof also has little input on the matter.

    Here is what my lab writeup says:
    ...An excellent technique to distinguish noise from signal is to trigger the scope on one detector and look at another. Noise seldom occurs simultaneously for two detectors. Record the threshold you found on each discriminator, then the value you ended up with and why you changed it.

    After outputting the logic pulses from each detector to an input on the scope, I find that detector A has a ton of pulses (as I would expect since it is the first detector and has noise, and proton, pion, and muon events). Detector B has few pulses.

    As the instructions point out, I should trigger on B and look at A. So I do this and adjust the threshold on A until what? Until I count that more pulses from A and B are simultaneous than not? I'm not sure how to exploit the fact given in the guide.

    Also, couldn't I just trigger on A and adjust the trigger value until it triggers every so often and not continuously? I would imagine this is the voltage at which noise pulses no longer trigger the scope.
    Last edited: Feb 10, 2009
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?