30TH INTERNATIONAL COSMIC RAY CONFERENCE Composition Measurements near the Second Knee with the Telescope Array Low- Energy Extension (TALE)

Cosmic rays with energies between 10 and 10 eV exhibit a rich range of features. The energy spectrum changes index at at least two points, known as the “second knee” and the “ankle”. There may be a composition change in this energy regime as well, perhaps indicative of a shift in predominance from galactic to extragalactic sources. The Telescope Array Low-Energy Extension — planned for construction in Millard County, Utah, USA — stands well poised to make decisive simultaneous measurements of cosmic ray energy spectra and composition in this transition region. Here, we present the results of simulation studies relevant to the design of the TALE detectors, and estimate the sensitivity of TALE to composition changes in the 10 eV decade.