Deuterium retention in reduced activation ferritic/martensitic steel EUROFER97 exposed to low-energy deuterium plasma
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Engineering topics
Publications and source records attributed to Hatano, Y..
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The experimental data of extensive air showers observed at Akeno have been analyzed to detect the gamma ray signal from Cyg X-3. After muon poor air showers are selected, the correlation of data acquisition time with 4.8 hours X-ray period is studied, giving the data concentration near the phase 0.6, the time of X-ray maximum. The probability that uniform backgrounds create the distribution is 0.2%. The time averaged integral gamma ray flux is estimated as (1.1 + or - 0.4)x 10 to the -14th power cm(-2) sec(-1) for Eo 10 to the 15th power eV and (8.8 + or - 5.0)x 10 to the 14th power cm(-2) sec(-1) for Eo 6 x 10 to the 14th power eV.
Anisotropy of cosmic rays is studied with extensive air showers (EAS) data by muon trigger. The present results support those obtained by electron trigger which suggest the significant anisotropy of second harmonics with phase around 100 deg in right ascension for showers of 10 to the 16th power - 10 to the 17th power eV, and predominant arrival direction of 230 deg in right ascension for muon-rich showers. It seems that the phase of the first harmonics in the energy range below 10 to the 11th power eV is about 300 deg in right ascension and the second harmonics near 6 x 10 to the 14th power eV is statistically significant with an amplitude of 0.39 + or - 0.13% in direction of 83 + or - 10 deg in right ascension.
As the first stage of the future huge array, the Akeno air shower array was expanded to about 20 sq. km. by adding 19 scintillation detectors of 2.25 sq m area outside the present 1 sq. km. Akeno array with a new data collection system. These detectors are spaced about 1km from each other and connected by two optical fiber cables. This array has been in partial operation from 8th, Sep. 1984 and full operation from 20th, Dec. 1984. 20 sq m muon stations are planned to be set with 2km separation and one of them is now under construction. The origin of the highest energy cosmic rays is studied.
With the use of Akeno calorimeter, the attenuation of particles in concrete is analyzed as the function of the shower size of 10 to the 5th power to 10 to the 7th power. The attenuation length does not depend much on the shower size but depends a little on the shower age. The average value is approx. 150 g/sq cm for s = 0.5 to 0.85 and approx. 40 g/sq cm for s = 0.85 to 1.15. These values and their fluctuations are consistent with the equi-intensity curves of extensive air showers (EAS).
An experimental study of the fast scintillation counter (FS) system to observe a shower disk structure at Mt. Norikura is described, especially the system performance and a pulse wave-form by a single charge particles. The photomultiplier tube (PT) pulse appears at the leading edge of the main pulse. To remove this PT-pulse from the main pulse, the frame of the scintillator vessel was changed. The fast triggering system was made to decrease the dead time which came from the use of the function of the self triggering of the storage oscilloscope (OSC). To provide a new field on the multi-parameter study of the cosmic ray showers, the system response of the FS system also improved as a result of many considerations.
The structure of the EAS shower disk, the arrival time distribution of charged particles at the core of the small or middle size shower, is measured at Mt. Norikura in Japan. Four fast scintillation counters with an area of 0.25 sq m and a fast trigger system are added to the Mt. Norikura EAS array for the study.
The properties of 10 to the 18th power - 10 to the 19th power eV EAS showers such as the electron lateral distribution, the muon lateral distribution ( 1Gev), the ratio of muon density to a electron density, the shower front structure and the transition effects in scintillator of 5cm thickness are investigated with the Akeno 4 sq km/20sq km array at far core distances between 500m and 3000m. The fluctuation of densities and arrival time increase rapidly at core distances greater than 2km.