BEXCO - Room B(103/104/105)
[CRI227] Estimate of the energy spectrum of the light component of cosmic rays in HAWC using the shower age and fraction of hit PMT
The High Altitude Water Cherenkov (HAWC) observatory is a ground-based air-shower detector designed to study the TeV gamma and cosmic ray windows. The observatory is composed of a densely packed array of 300 water Cherenkov tanks, 4.5 m deep and 7.3 diameter with 4 photomultipliers (PMT) each, distributed on a 22,000 m2 surface. The instrument registers the number of hit PMT’s as well as the timing information and the total charge seen by the photomultipliers during the shower event. From the analysis of these data, shower observables such as the arrival direction, the core position at ground, the age and the primary energy are estimated. In this work, we study the distribution of the shower age vs the fraction of hit PMT’s of a subsample of cosmic ray data collected by HAWC and show that it contains information about the composition of cosmic rays. We exploit this information to get a preliminary estimation of the energy spectrum of the light component of cosmic rays, i.e. protons plus helium nuclei, from the HAWC data.