Since cosmic ray was discovered about 100 years ago, the mechanism which generates huge energy has been always the subject of interest.
In order to study the origin of the extremely high energy cosmic ray, highly precise data of extended air shower has been acquired by two huge detectors
(Telescope Array and Pierre Auger Observatory) which have started observation from the beginning of the...
For long-term UHECR observations, the gain calibration of photo-multiplier tubes (PMTs) in the Fluorescence Detector (FD) of the Telescope Array (TA) is crucially important to determine UHECR energies. Current uncertainty of PMT gain in TA FD is estimated to be 11% by adding 8% uncertainty of gain calibration using CRAYS in 2008 and 8% uncertainty of on-site monitoring using YAP pulser in...
The method of composition studies with the Telescope Array surface detector (SD) data is presented. The method is based on the multivariate decision tree analysis of SD observables. Preliminary results of the study will be reported at the conference.
We are developing a unmanned aerial vehicle (UAV), which is called "Opt-copter", carrying a calibrated light source for fluorescence detector (FD) calibration of the Telescope Array (TA) experiment.
The "Opt-copter" is equipped with a high accuracy GPS device and a LED light source in the shape of a dodecahedron. A positioning accuracy of the GPS mounted on the UAV is 0.1 m, which meets the...
In near future, it is expected that sources of ultra-high-energy cosmic rays (UHECRs) can be identified, because the Telescope Array experiment reported that there is a Hotspot in the UHECR arrival direction. However, it is required to observe UHECRs with higher statistics. Moreover, the mass composition should be determined, which is important information for anisotropy study. Then, we should...
The data acquisition (DAQ) system of the surface detectors (SDs) of the TAx4 and the TALE experiment will be presented. Each SD records signals with 50MHz FADCs and sends the data to a central communication center (or the “communication tower”) via a wireless network system. The techniques employed here are based on the currently-running DAQ system of the Telescope Array, and there are some...
An important and remained problem for the observation of UHECRs by air shower experiments is the uncertainty arising from the hadronic interaction models.
Since we rely on particle production, namely air shower development of UHECRs described by the interaction models, it is necessary to verify these interaction models at accelerators as high energy as possible.
Large Hadron Collider forward...
The uncertainty when inferring the mass composition from Xmax distributions comes mainly from unknown uncertainties on
For any experiment aiming at the observation of Ultra High Energy Cosmic Rays (UHECR's) from space, one key measurement is related to the UV emissions produced in the Earth’s atmosphere. In view of planned missions under study (KLYPVE/K-EUSO, JEM-EUSO, EUSO-FF) at the International Space Station (ISS) and on board of free-flyer satellites, a small, compact UV telescope, Mini-EUSO, is being...
Diffractive and non-diffractive collisions are totally different hadronic interaction processes, the diffractive processes are hardly predicted theoretically. This leads to the significant differences in the treatments of diffraction in the hadronic interaction model. Due to the very forward detector has unique sensitivity to the diffractive processes, it can be a powerful detector for the...
The Non-Imaging CHErenkov Array (NICHE) is a low energy extension to Telescope Array and TALE using an array of closely spaced (70--100 m) light collectors covering an area of up to 1/4 square km. The target is cosmic rays with energies above the "knee", including the "transition region" above which Galactic cosmic rays are no more confined by the galactic magnetic field. It will be deployed...
Telescope Array (TA) is international joint experiment observing ultra-high energy cosmic rays. TA employs fluorescence detection technique to observe cosmic rays. In this technique, the existence of cloud significantly affects quality of data. Therefore, cloud monitoring provides important information. We are developing two new methods for evaluating night sky weather with pictures taken by...
The estimation of invisible energy is central for experiments where only the electromagnetic component of the air shower is measured. This estimation is based on complex Monte Carlo simulations where the influence of the parameters describing the high energy hadronic interactions is difficult to unravel.
The Heitler-Matthews cascade model has been shown to be a powerful tool to
understand the...
The UHECR data collected by the TA and Auger collaborations show some interesting differences in the spectrum as well as in possible anisotropies. Assuming that they do not simply reflect some statistical and/or systematic uncertainties, but on the contrary capture distinct features associated with different regions in the sky, it is interesting to investigate the implications of such...
Three fluorescence detector experiments, HiRes, Telescope Array, and Pierre Auger, agree that the cosmic ray composition is light, probably protonic in 10^18.0 to 10^18.5 eV range. This energy range is well above the critical energy of the galactic magnetic field (GMF). Our simulations of the GMF field show that if these cosmic rays were of galactic origin, there would be an anisotropy in...
The number of muons from the ultra-high energy cosmic rays (UHECRs) is measured with the surface detectors (SDs) on the ground. Its MC prediction depends on hadronic interaction models and the composition. By comparing the measured number of muons with the MC prediction, hadronic models can be tested.
The Pierre Auger Observatory reported that the number of muons measured by water Cherenkov...
The Telescope Array experiment installed the electron accelerator in order to calibrate the fluorescence detector by shooting 40 MeV electrons into the atmosphere. This accelerator is also useful to investigate the radio detection techniques for the cosmic ray observation. Using this accelerator, four experimental groups have studied individual radio detection method at different frequency...
The purpose of the RHICf(Relativistic Hadron Ion Collider forward) experiment is the verification of hadronic interaction models, which is necessary to precisly understand air-shower developments induced by high energy cosmic-rays.We measure the forward neutral particles by using a calorimeter detector installed near the STAR detector. The RHICf detector is the LHCf - Arm1 detector brought...
The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a design concept for the next generation of ultra-high energy cosmic ray (UHECR) observatories, addressing the requirements for a large-area, low-cost detector suitable for measuring the properties of the low flux of cosmic rays at the highest energies. In the FAST design, a large field of view is covered by a few pixels at...
The Large Hadron Collider forward (LHCf) experiment is designed for verification of hadronic interaction models used in cosmic ray physics. We have measured neutral particles, especially neutrons, in very forward region of √s = 13TeV proton-proton collision at CERN-LHC in order to measure inelasticity. For the purpose, the LHCf detector was updated in 2014 by using GSO scintillator to improve...
Two types of orbital detectors of ultra high energy cosmic rays are being developed nowadays: telescope with reflecting optical systems (TUS/KLYPVE and OWL mission with Schmidt optics) and complex lens system (EUSO/JEM-EUSO mission). They will cover much larger areas than existing ground-based arrays and almost uniformly monitor the celestial sphere. The TUS detector is the pioneering mission...
