The origin of cosmic rays remains one of the greatest puzzles of modern astrophysics after more than 50 years since their first registration. Several ground experiments have reported the rate registered at its height of operation. To continue with the study of cosmic rays, we propose obtain the rate at different heights in the Earth's atmosphere, developing a small and portable ultraviolet radiation detector, consisting of a scintillation plastic, a PMT, and a fast DAQ system. In this work, we present the design and construction of the small UV detector, the energy of the events and the rate recorded during the journey from university of BUAP campus to Pico de Orizaba national park in Mexico, covering a range of heights 2200-4200 m.a.s.l, approximately. The energy of each event its reported considering all the calibration parameters of detector. The rate obtained will compared with the number of registered particles per second, provided by experiments operating at heights known as AUGER, LAGO, etc.