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

Muon lifetimes

  1. Apr 5, 2008 #1
    Hi,

    I'm starting a prac on muon lifetimes and we have been asked to calculate the range of energies suitable for the experiment...

    Thinking about this, I was a bit stumped as to what we were supposed to be calculating... Is this a limitation of the detection equipment? Or do low energy muons never make it to earth? and high energy muons are too fast to detect?

    These are the only other reasons I could come up with!

    Any help would be greatly appreciated!

    Thanks!
     
  2. jcsd
  3. Apr 6, 2008 #2

    Astronuc

    User Avatar

    Staff: Mentor

    Well muons have a very short half-life, ~ 2.2 us, in the rest frame. Range (energy) is one issue, but also where the precursor reaction takes place, part of which is the avaible energy to the muon from pion decay.

    http://hyperphysics.phy-astr.gsu.edu/hbase/particles/lepton.html#c3

    http://hyperphysics.phy-astr.gsu.edu/hbase/particles/muonatm.html

    http://hyperphysics.phy-astr.gsu.edu/hbase/astro/cosmic.html#c2

    http://teachers.web.cern.ch/teachers/archiv/HST2000/teaching/expt/muoncalc/lifecalc.htm

    This might be of interest - http://web.mit.edu/8.13/www/JLExperiments/JLExp14.pdf
     
    Last edited: Apr 6, 2008
  4. Apr 6, 2008 #3
    ok.. so high energy muons won't stop, but why aren't low energy muons useful?
     
  5. Apr 6, 2008 #4

    Astronuc

    User Avatar

    Staff: Mentor

    I'm not sure what one means by useful - besides detecting muons, how is one trying to use them.

    Range (from birth to decay) is function of energy. If the energy is too low, the muon doesn't cover much distance before it decays.

    At higher energies, a muon could conceiveably travel through a detector. Way back when, I used a coincidence detector in physics lab to detect muons.

    Has one considered the energy loss of the muon in comparison with that of a beta particle (or electron)?
     
  6. Apr 6, 2008 #5

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Because they won't live to make it to your detector in sufficient numbers. Assume most muons are created at heights above 15km up. Using their known lifetimes (about 2.2 mu s) and an exponential decay law, calculate the minimum energy needed for say 1, in 10^5 muons created to survive the journey to the detector.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Muon lifetimes
  1. Muon decay lifetime (Replies: 9)

  2. Muon Lifetime Experiment (Replies: 10)

  3. Leptonic lifetimes (Replies: 16)

Loading...