Design and implementation of the Photo-Detector Module electronics for the EUSO-Balloon, prototype of the JEM-EUSO telescope

Abstract

A key feature of the JEM-EUSO observatory for Ultra High Energy Cosmic Rays (UHECRs) search is the electronics, and in particular the Photo-Detector Module (PDM) on the focal surface of an advanced diffractive optical system. As a pathfinder experiment for this space-based mission, over the last 3 years the EUSO-Balloon project has been developed to observe the ultraviolet background from the edge of the atmosphere on board a stratospheric balloon. August 2014, the EUSO Balloon was successfully operated 8-hour balloon flight over Timmins, Ontario, Canada. The EUSO-Balloon experiment uses a detector consisting of one Photo-Detector Module, identical to the 137 modules that will be present on the JEM-EUSO focal surface. UV light generated by ultra high-energy air showers passes the optics, UV filter, and impacts the Multi Anode Photo Multiplier Tubes (MAPMTs). UV photons are converted by the MAPMT photocathode into electrons, which are multiplied by the MAPMTs dynode and fed into a Elementary Cell - Application Specific Integrated Circuit (EC-ASIC) boards. These EC-ASIC boards in turn perform the photon counting and charge estimation, by counting the single photoelectron emitted during each Gate Time Unit (of 2.5 us each). The PDM board interfaces with these ASIC boards, providing them with power and configuration parameters as well as collecting data from the external trigger. In this paper, I will describe the details of the design and the fabrication of the PDM, as well as its EUSO-Balloon flight results.