{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

cosmic_rays - Experiments in Modern Physics Cosmic Rays Rex...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Experiments in Modern Physics: Cosmic Rays Rex Tayloe, Department of Physics, Indiana University 1/10/04 (revised from original by HOM, 12/98) Last Revised: 1/15/04 Goals Understand the 2 workings of high energy physics detectors and electronics. Use these to measure the rate of cosmic rays and the lifetime of the muon. Introduction Fast atomic particles are moving through interstellar space. The earth is thus under a constant bombardment by protons, and, to a lesser degree, by light nuclei (see ref. [1], fig.20.1). The average energy of these particles of in the order of 1 GeV, but can range to energies higher than those that can be produced by accelerators. When the particles make contact with the upper atmosphere, they start to undergo nuclear reactions with the air. Almost none of them reach the surface of the earth. However, the products of these reactions can survive. In high-energy collisions in the atmosphere, pions are produced in abundance. Pions have a mean life of only 26 ns (at the speed of light, they travel only about 8m). When they decay, they produce a muon ( ) and a neutrino ( ). The charged muons lose energy in the atmosphere, but an initial energy of about 1 GeV is enough to reach the surface of the earth. The muon is also unstable, decaying into an electron and two neutrinos with a mean life of about 2 s. Thus, it seems that the muons should decay before they reach the surface. However,
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern