Atmospheric monitoring with the Fluorescence detector Array of Single-pixel Telescopes

Dušan Mandát ,Xiaochen Ni,Toshihiro Fujii,L Nožka ,P Hamal ,P Trávníc̆ek ,M Malacari ,P Privitera ,P Horváth ,M Pech ,J A Bellido ,Petr Schovánek ,L Chytka ,M Hrabovský ,M Palatka ,Justin M Albury ,John Farmer ,J N Matthews ,S B Thomas

doi:10.1051/epjconf/201919702002

Abstract

The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a proposed low-cost, largearea, next-generation experiment for the detection of ultrahigh-energy cosmic rays (UHECRs) via the atmospheric fluorescence technique. Two FAST telescopes are currently installed and operating at the Black Rock Mesa site of the Telescope Array Experiment in Utah, USA. Knowledge of the properties of the atmosphere above the detector is of utmost importance for the analysis and reconstruction of the energy and trajectory of UHECRs measured with an atmospheric fluorescence telescope. The FAST experiment uses all sky camera (FASCam) and sky quality monitor (SQM) for the detection of clouds and quantification of the night-sky background light in the field-of-view of the telescopes. Measurements of a vertically-fired ultra-violet laser at a distance of 21 km from the FAST telescopes are used to infer the transparency of the atmosphere above the detector through comparison with simulations.

Highlights

The Fluorescence detector Array of Single-pixel Telescopes (FAST) [1] is a design concept for a low-cost, ground-based fluorescence detector (FD)
In October 2016, the first full-scale FAST prototype was installed in a dedicated building at the Telescope Array site in central Utah, USA, with a second telescope following in an adjacent building in September 2017
The FAST all sky camera (FASCam) can be used for monitoring of the night-sky brightness (NSB) in the field of view of the FAST telescopes

Summary

Introduction

The Fluorescence detector Array of Single-pixel Telescopes (FAST) [1] is a design concept for a low-cost, ground-based fluorescence detector (FD). A FAST telescope consists of just four pixels covering a 30◦×30◦ patch of the sky with a ∼1 m2 collecting area. In October 2016, the first full-scale FAST prototype was installed in a dedicated building at the Telescope Array site in central Utah, USA, with a second telescope following in an adjacent building in September 2017. Both telescopes are fully remotely-operable, and record data in coincidence with the adjacent Black Rock Mesa FD site. Collected data include measurements of air showers, as well as vertical laser traces from the Telescope Array’s Central Laser Facility (CLF)

Atmospheric monitoring devices

Measurement of the night-sky background using the FAST telescopes

Measurement of the night-sky background using the FASCam

Atmospheric characterisation using the Central Laser Facility

Findings

Conclusions