The University of Utah
Department of Physics & Astronomy at the University of Utah

Priti Shah Thesis Defense 05/10/12

Thesis Defense

Priti Shah

Thursday, May 10, 2012
3:00pm (206 JFB)

Title: Monocular Measurement of the Ultra High Energy Cosmic Ray Spectrum while Relaxing the Profile Constraint


Cosmic rays are charged particles of galactic and extragalactic origin. In the ultra high energy regime, due to their extremely low flux, cosmic rays can only be observed indirectly via an extensive air shower induced when they interact in the Earth's atmosphere. The Telescope Array (TA) experiment, the largest experiment in operation in the northern hemisphere, observes the longitudinal profile of the fluorescence light from these extensive air showers via telescopes. The Middle Drum fluorescence telescope station utilizes the same equipment as the HiRes-I site of the High Resolution Fly's Eye (predecessor to Telescope Array) experiment. The equipment has simply been reconfigured. As HiRes-I, the telescopes viewed 3-17o in elevation and nearly 360o in azimuth. As a result of this, the track length in the cameras tended to be short. In the Telescope Array configuration, the telescopes view 3-31o in elevation, but only about 120o in azimuth, however, the resulting track lengths are significantly longer. With the short track lengths, one needed to make an assumption about the shape of the profile; that it had a Gaisser-Hillas shape. The longer track lengths make this unnecessary. I have analyzed the data using a Time vs Angle geometry method. The results show an ultra high energy cosmic ray energy spectrum that is consistent with the previous results of the HiRes experiment as well as that measured by the TA surface detectors.

Follow Us

Support Us

Make A Difference

Outreach: The Department of Physics & Astronomy at the U

Community Outreach

Scholarships: The Department of Physics & Astronomy at the U

Academic Scholarships

General_Development: The Department of Physics & Astronomy at the U

Other Areas
of Support


Our Newest Program:

Crimson Laureate Society


Click to download full size.

The Department of Physics & Astronomy at the U


Science, it makes us all go


Even Our English Majors Study Physics


The Formula For The Perfect Pass


  • Dept of Physics & Astronomy • 201 James Fletcher Bldg. 115 S. 1400 E., Salt Lake City, UT 84112-0830
  • PHONE 801-581-6901
  • Fax 801-581-4801
  • ©2018 The University of Utah