Upgrade of a data acquisition system for SciBar Cosmic Ray Telescope (SciCRT) at Mt. Sierra Negra, Mexico

Abstract

SciCRT (SciBar Cosmic Ray Telescope) is a new project to observe cosmic rays via a full active scintillator tracker. Our aim is to detect high energy solar neutrons produced by the interaction between accelerated ions and the solar atmosphere and to observe muons to research anisotropy of Galactic Cosmic Rays (GCRs). In the previous ICRC in Brazil, we reported that the detector has been installed at Mt. Sierra Negra (4,600 m above sea level) in April 2013. We also reported that the current VME-based data acquisition (DAQ) system does not have enough capacity to deal with GCR-induced neutrons at such a high altitude mountain. Moreover noises produced by the VME readout prevent the DAQ system counting the trigger rate and make the current trigger process complicated. Therefore we have developed a fast readout DAQ system, optimized to our experimental environment within an Open-It project. We employed SiTCP, a hardware-based network processor, developed for high energy physics. We have developed a brand-new back-end board (BEB) based SiTCP and tested it at Mt. Sierra Negra in 2014. Then we determined the definitive design for the new BEB. We replaced the muon and a part of the neutron DAQ system with the new DAQ system in June, 2015. We will introduce the basic performance evaluation and the configuration of the new DAQ system which is operated at Mt. Sierra Negra.