Browsing by Autor "T. Kaneko"

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A small air-shower array at Mount Chacaltaya
(Elsevier BV, 1996) F. Kakimoto; S. Ogio; Y. Shirasaki; N. Gironda; T. Kaneko; H. Yoshii; Toshihiko Baba; K. Nishi; N. Tajima; Y. Yamada
Arrival directions of large air showers, low-mu showers and old-age low-mu air showers observed at St. Chacaltaya
(NASA Headquarters, 1985) T. Kaneko; K. Hagiwara; H. Yoshii; N. Martinić; L. Siles; P. Miranda; F. Kakimoto; Toru Obara; N. Inoue; K. Suga
Arrival directions of air showers with primary energies in the range 10 to the 16.5 power eV to 10 to the 18th power eV show the first harmonic in right ascension (RA) with amplitude of 2.7 + or - 1.0% and phase of 13-16h. However, the second harmonic in RA slightly seen for showers in the range 10 to the 18th power eV to 10 to the 19th power eV disappeared by accumulation of observed showers. The distribution of arrival directions of low-mu air showers with primary energies around 10 to the 15th power eV observed at Chacaltaya from 1962 to 1967 is referred to, relating to the above-mentioned first harmonic. Also presented in this paper are arrival directions of old-age low-mu air showers observed at Chacaltaya from 1962 to 1967, for recent interest in gamma-ray air showers.
Chemical composition of primary cosmic rays with energies from 1015 to 1016.5 eV
(Elsevier BV, 2001) Y. Shirasaki; F. Kakimoto; S. Ogio; N. Gironda; M. Takeda; T. Kaneko; H. Yoshii; Toshihiko Baba; Sakae Sano; K. Nishi
Electrons in large air showers observed at 5200 m above sea level
(IOP Publishing, 1979) C. Aguirre; F. Kakimoto; K. Kamata; T. Kaneko; P. K. MacKeown; Y. Mizumoto; Kazuaki Murakami; M. Nagano; H. Nakatani; K. Nishi
Results are presented for the lateral distribution and the longitudinal development of electrons between an atmospheric depth of 550 g cm-2 and 1100 g cm-2 in air showers with sizes 3*106 to 5*109 observed at Mount Chacaltaya. The lateral distribution is compared with those determined at mountain altitudes and at sea level by other groups. The longitudinal development is also compared with the results of other groups and with theoretical predictions under various models of nuclear interactions.
Energetic delayed hadrons in large air showers observed at 5200m above sea level
(1985) T. Kaneko; K. Hagiwara; H. Yoshii; N. Martinić; L. Siles; P. Miranda; F. Kakimoto; I. Tsuchimoto; N. Inoue; K. Suga
Energetic delayed hadrons in air showers with electron sizes in the range 10 to the 6th power to 10 to the 9th power were studied by observing the delayed bursts produced in the shield of nine square meter scintillation detectors in the Chacaltaya air-shower array. The frequency of such delayed burst is presented as a function of electron size, core distance and sec theta.
Muons in large air showers observed at 5200 m above sea level
(IOP Publishing, 1979) C. Aguirre; A Treppi; F Kakimato; K Kamata; T. Kaneko; P. K. MacKeown; Y. Mizumoto; Kazuaki Murakami; H. Nakatani; K. Nishi
Results are presented for the lateral distribution of muons with energies above 600 MeV in air showers with electron sizes 107 to 109 observed at Mount Chacaltaya. Results are also presented for the muon size spectrum at 644 g cm-2 and the longitudinal development of muons from 550 g cm-2 to 990 g cm-2 for intensities 10-8 m-2 s-1 sr-1 to 10-10 m-2 s-1 sr-1.
Search for GeV GRBs at Chacaltaya
(1998) A. Castellina; P. L. Ghia; C. Morello; G. Trinchero; P. Vallania; S. Vernetto; G. Navarra; O. Saavedra; H. Yoshii; T. Kaneko
In this paper we present the results of a search for GeV Gamma Ray Bursts made by the INCA experiment during the first 9 months of operation. INCA, an air shower array located at Mount Chacaltaya (Bolivia) at 5200 m a.s.l., has been searching for GRBs since December 1996. Up to August, 1997, 34 GRBs detected by BATSE occurred in the field of view of the experiment. For any burst, the counting rate of the array in the 2 hours interval around the burst trigger time has been studied. No significant excess has been observed. Assuming for the bursts a power low energy spectrum extending up to 1 TeV with a slope α=−2 and a duration of 10 s, the obtained 1 GeV-1 TeV energy fluence upper limits range from 7.9 10−5 erg cm−2 to 3.5 10−3 erg cm−2 depending on the event zenith angles.
Search for GeV GRBs with the INCA experiment
(EDP Sciences, 1999) Renán Cabrera; A. Castellina; P. L. Ghia; F. Kakimoto; T. Kaneko; C. Morello; G. Navarra; K. Nishi; O. Saavedra; G. Trinchero
INCA is an air shower array located at Mount Chacaltaya in Bolivia, at 5200 m a.s.l., searching for Gamma Ray Bursts of energy GeV. The results presented here concern a GRB search made in correlation with 70 events recorded by BATSE since December 1996 to August 1998. For every burst, the INCA counting rate has been studied both during the BATSE detection time and in 2 hours around. No significant excess has been found in any of the trials. Assuming for the burst a power low energy spectrum extending up to 1 TeV with a slope and a time duration of 10 s, the obtained energy fluence upper limits range from to depending on the event zenith angle.
Searches for Ultra–High‐Energy Gamma Rays from SN 1987A and Centaurus X‐3
(IOP Publishing, 1996) H. Yoshii; T. Baba; T. Kaneko; K. Suga; F. Kakimoto; S. Ogio; Y. Shirasaki; N. Gironda; M. Teshima; Y. Toyoda
Searches for gamma rays above 100 TeV from SN 1987A and above 50 TeV from Cen X-3 were carried out with an air shower array at Mount Chacaltaya over a period of 3 years. The array, which consists of 13 4 m2 and 28 1 m2 scintillation detectors, was located on a slope of about 30 facing southward to e ectively observe air showers coming from the directions of these sources. In the analysis, a selection by shower age parameter was applied to reduce the background due to showers initiated by protons or nuclei.