The prototype high-resolution Fly's Eye cosmic ray detector Abu-Zayyad, T; Al-Seady, M; Belov, K ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2000, Volume:
450, Issue:
2
Journal Article
Peer reviewed
The High-Resolution Fly's Eye (HiRes) is an observatory for the highest energy cosmic rays. It detects the nitrogen fluorescence light induced by the passage of giant cosmic ray extensive air showers ...through the atmosphere. A two-site prototype of the observatory was operated from September 1994 to November 1996. In this paper we describe the components of that detector, and the procedures used to calibrate the detector and characterise the atmosphere. Data collected by the HiRes prototype are being used for physics studies, including an analysis of the cosmic ray mass composition in the energy range from 10
17 to
10
18
eV
.
The average mass composition of cosmic rays with primary energies between 10(17) and 10(18) eV has been studied using a hybrid detector consisting of the High Resolution Fly's Eye (HiRes) prototype ...and the MIA muon array. Measurements have been made of the change in the depth of shower maximum and the muon density as a function of energy. The results show that the composition is changing from a heavy to lighter mix as the energy increases.
The HiRes experiment has now completed data taking. We describe the experiment, the detector and atmospheric calibration and studies to improve precision of knowledge of air-fluorescence efficiency. ...The current results on the monocular and stereo spectrum and stereo-based composition measurements are summarized. Possible correlation of stereo data event directions with a subset of Bl-Lac objects is discussed.
The Utah Fly's Eye detector has revealed a change in the cosmic ray composition which is correlated with structure in the all-particle energy spectrum. The data can be fitted by a simple model of a ...steep power law spectrum of heavy nuclei which is overtaken at high energies by a flatter spectrum of protons. The transition occurs near 10sup 18.5 eV. Anisotropy is not detected, so the high-rigidity particles above the transition energy do not originate in the disk of the Galaxy. An outstanding event of 3times10sup 20 eV implies that the highest energy particles originate in the contemporary era of the Universe.
This paper summarizes the experimental contributions to the Workshop on Physics at the End of the Galactic Cosmic Ray Spectrum, held at the Aspen Physics Institute, Aspen, Colorado in April 2005. ...Experimental talks presented during the five day Workshop are summarized. Results of discussions of the Direct Measurement Working Group and the Indirect Measurement Working Group are presented.
Aim of the TA-EUS0 project is to install a prototype of the JEM-EUSO telescope on the Telescope Array site in Black Rock Mesa, Utah and perform observation of natural and artificial ultraviolet ...light. The detector consists of one Photo Detector Module (PDM), identical to the 137 present on the JEM-EUSO focal surface. Each PDM is composed by 36 Hamamatsu multi-anode photomultipliers (64 channels per tube), for a total of 2304 channels. Front-End readout is performed by 36 ASICS, with trigger and readout tasks performed by two FPGA boards that send the data to a CPU and storage system. Two, 1 meter side square Fresnel lenses provide a field-of-view of 8 degrees. The telescope will be housed in a container located in front of the fluorescence detector of the Telescope Array collaboration, looking in the direction of the ELF (Electron Light Source) and CLF (Central Laser Facility). Aim of the project is to calibrate the response function of the EUSO telescope with the TA fluorescence detector in presence of a shower of known intensity and distribution. An initial run of about six months starting from end 2012 is foreseen, during which we expect to observe, triggered by TA electronics, a few cosmic ray events which will be used to further refine the calibration of the EU SO-Ground with TA. Medium term plans include the increase of the number of PDM and therefore the field of view.
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