A. Taketa

The MU-RAY project: detector technology and first data from Mt. Vesuvius

Muon Radiography allows to map the density of a volcanic cone. It is based on the measurement of the attenuation of the flux of muons present in the cosmic radiation on the ground. The MU-RAY project has developed an innovative detector designed for the muon radiography. The main features are the low electric power consumption, robustness and transportability, good spatial resolution and muon time of flight measurement. A 1 m2 detector prototype has been constructed. and collected data at Mt. Vesuvius for approximately 1 month in spring 2013. A second campaign of measurement has been performed at the Puy de Dome, France, in the last four months of 2013. In this article the principles of muon radiography, the MU-RAY detector and the first results from the collected data will be described.

Calibration of photomultiplier tubes for the fluorescence detector of telescope array experiment using a Rayleigh scattered laser beam

Abstract We performed photometric calibration of the PhotoMultiplier Tube (PMT) and readout electronics used for the new fluorescence detectors of the Telescope Array (TA) experiment using Rayleigh scattered photons from a pulsed nitrogen laser beam. The experimental setup, measurement procedure, and results of calibration are described. The total systematic uncertainty of the calibration is estimated to be 7.2%. An additional uncertainty of 3.7% is introduced by the transport of the calibrated PMTs from the laboratory to the TA experimental site.

Measurement of ultra-high energy cosmic rays by telescope array (ta)

The Telescope Array (TA) is a large scale ground experiment in Utah, USA for the measurement of extensive air showers from the ultra-high energy cosmic rays. Its construction is completed in March, 2008 and the data taking started.

Comparison of CORSIKA and COSMOS simulations

Ultra‐high‐energy cosmic rays (UHECRs) refer to cosmic rays with energy above 1018 eV. UHECR experiments utilize simulations of extensive air shower to estimate the properties of UHECRs. The Telescope Array (TA) experiment employs the Monte Carlo codes of CORSIKA and COSMOS to obtain EAS simulations. In this paper, we compare the results of the simulations obtained from CORSIKA and COSMOS and report differences between them in terms of the longitudinal distribution, Xmax‐value, calorimetric energy, and energy spectrum at ground.

A Test of New Large Aperture Photodetectors in a Water Cherenkov Detector

Yuji OKAJIMAa, Miao JIANGb, Daisuke FUKUDAc, Ryosuke AKUTSU, Yusuke SUDAd, Seiko HIROTAb, Shoei NAKAYAMAe, Masato SHIOZAWAe, Masashi YOKOYAMAd, Yoshinari HAYATOe, Hidekazu TANAKAe, Masayuki NAKAHATAe, Tsuyoshi NAKAYAb, Masahiro KUZEa, Yusuke KOSHIOc, Akimichi TAKETA f aDepartment of Physics, Tokyo Institute of Technology bDepartment of Physics, Kyoto University cDepartment of Physics, Okayama University dDepartment of Physics, The University of Tokyo eKamioka Observatory, Institute for Cosmic Ray Research, The University of Tokyo f Earthquake Research Institute, The University of Tokyo

Detailed performance evaluation of a new 20-inch photomultiplier tube with a Box and Line dynode

Yasuhiro Nishimuraa, Ryosuke Akutsua, Yusuke Sudab, Miao Jiangc, Seiko Hirotac, Daisuke Fukudad , Masahiro Kuzee, Masaki Ishitsukae, Masayuki Nakahataa, Masato Shiozawaa, Yoshinari Hayatoa, Shoei Nakayamaa, Hidekazu Tanakaa, Masashi Yokoyamab, Tsuyoshi Nakayac, Akihiro Minaminoc, Akimichi Taketa f , Yoshihiko Kawaig, Takayuki Ohmurag, Masatoshi Suzukig a Institute for Cosmic Ray Research, University of Tokyo b Department of Physics, University of Tokyo c Department of Physics, Kyoto University d Department of Physics, Okayama University e Department of Physics, Tokyo Institute of Technology f Earthquake Research Institute, University of Tokyo g Hamamatsu Photonics K.K.

Temperature Dependence Measurement of a Hybrid Photo-Detector for Hyper-Kamiokande

1 Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan 2 Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582, Japan 3 Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan 4 Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551, Japan 5 Earthquake Research Institute, University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan 6 Hamamatsu Photonics K.K., Hamamatsu, Shizuoka, 430-8587, Japan

Search for small clusters by auto‐correlation analysis from Telescope Array

The Telescope Array (TA) experiment detects air showers induced by extremely high energy cosmic rays in the middle west of Utah, USA. The TA experiment consists of two different types of detector such as atmospheric fluorescence detectors (FDs) and surface array particle detectors (SDs). The SD observation started in March 2008. This paper describes the search for the small scale clusters from 850‐days TA SD data by auto‐correlation method for several energy thresholds. As a result, there is no indication of small scale clusters by TA SD.

Anisotropy and point sources searches in the Telescope Array data

The first two years of the Telescope Array surface detector data are analysed for anisotropy. First, we calculate the angular correlation function of the cosmic ray events at energies larger 10 and 40 EeV and show that there is no significant clustering either at small or large angular scales. We then test previously existing claims for correlation with putative classes of point sources of UHECR.