14 research outputs found
The surface detector array of the Telescope Array experiment
The Telescope Array (TA) experiment, located in the western desert of
Utah,USA, is designed for observation of extensive air showers from extremely
high energy cosmic rays. The experiment has a surface detector array surrounded
by three fluorescence detectors to enable simultaneous detection of shower
particles at ground level and fluorescence photons along the shower track. The
TA surface detectors and fluorescence detectors started full hybrid observation
in March, 2008. In this article we describe the design and technical features
of the TA surface detector.Comment: 32 pages, 17 figure
New air fluorescence detectors employed in the Telescope Array experiment
Since 2007, the Telescope Array (TA) experiment, based in Utah, USA, has been
observing ultra high energy cosmic rays to understand their origins. The
experiment involves a surface detector (SD) array and three fluorescence
detector (FD) stations. FD stations, installed surrounding the SD array,
measure the air fluorescence light emitted from extensive air showers (EASs)
for precise determination of their energies and species. The detectors employed
at one of the three FD stations were relocated from the High Resolution Fly's
Eye experiment. At the other two stations, newly designed detectors were
constructed for the TA experiment. An FD consists of a primary mirror and a
camera equipped with photomultiplier tubes. To obtain the EAS parameters with
high accuracies, understanding the FD optical characteristics is important. In
this paper, we report the characteristics and installation of new FDs and the
performances of the FD components. The results of the monitored mirror
reflectance during the observation time are also described in this report.Comment: 44 pages, 23 figures, submitted to NIM-
Gain monitoring of telescope array photomultiplier cameras for the first 4 years of operation
The stability of the gain of the photomultiplier (PMT) camera for the Fluorescence Detector (FD) of the Telescope Array experiment was monitored using an 241Am loaded scintillator pulsers (YAP) and a diffused xenon flasher (TXF) for a selected set of 35 PMT-readout channels. From the monitoring of YAP pulses over four years of FD operation, we found slow monotonic drifts of PMT gains at a rate of -1.7???+1.7%/year. An average of the PMT gains over the 35 channels stayed nearly constant with a rate of change measured at -0.01??0.31(stat)??0.21(sys)%/year. No systematic decrease of the PMT gain caused by the night sky background was observed. Monitoring by the TXF also tracked the PMT gain drift of the YAP at 0.88??0.14(stat)%/year.close0
The energy spectrum of Telescope Array's Middle Drum detector and the direct comparison to the High Resolution Fly's Eye experiment
0info:eu-repo/semantics/publishe
Energy spectrum of ultra-high energy cosmic rays observed with the Telescope Array using a hybrid technique
We measure the spectrum of cosmic rays with energies greater than 10(18.2) eV with the fluorescence detectors (FDs) and the surface detectors (SDs) of the Telescope Array Experiment using the data taken in our first 2.3-year observation from May 27, 2008 to September 7, 2010. A hybrid air shower reconstruction technique is employed to improve accuracies in determination of arrival directions and primary energies of cosmic rays using both FD and SD data. The energy spectrum presented here is in agreement with our previously published spectra and the HiRes results. (C) 2014 Elsevier B.V. All rights reserved.close