[en] An atmospheric interaction accompanying big Halo was detected in Chacaltaya emulsion chamber No.19. There are observed two peculiar characteristics. One is the existence of big Halo of a size 2 cm in radius at family center and the other rich in hadrons. Comparison is made with events of same nature including the biggest Andromeda event

[en] At present the study of nuclear interactions induced by cosmic rays is the unique source of information on nuclear interactions in the energy region above 10 to the 15th power eV. The phenomena in this energy region are observed by air shower arrays or emulsion chambers installed at high mountains. An emulsion chamber is a pile of lead plates and photo-sensitive layers (nuclear emulsion plates and/or X-ray films) used to detect electron showers. High spatial resolution of photographic material used in the emulsion chamber enables the observation of the phenomena in detail, and recent experiments using emulsion chamber with large area are being carried out at high mountain altitudes by several groups in the world

No abstract available

[en] Kinetics equations using two assumptions describe an ideal cascade with accuracy. Using the kinetics equations, it is found that if the decrease of the separation factor in a selected stage is small, the product can be withdrawn at the product assay allowed for shipment without stopping the operation of the ideal cascade composed of the model centrifuges (approximately 4 kg SWU/yr, α = 1.135). Moreover, the fraction of centrifuges permissible to stop in case of an accident is found to be 4 to 5 percent of the model centrifuges in each stage in the enriching section of the ideal cascade. (U.S.)

[en] Five years have passed since the Fukushima Nuclear Power Plant (NPP) accident, moving the problems in Fukushima from an acute nuclear disaster to a chronic environmental contamination with complicated problems such as psychological, social, economic and political consequences. Countermeasures aimed at human protection during the emergency period including evacuation, sheltering, and control of the food chain were implemented in a timely manner by the Japanese government. However, there is an apparent need for improvement, especially in the areas of nuclear safety and protection, and also in the management of radiation health risk during and even after the accident.

[en] ODS steels based on a 9-12Cr composition were developed with modified grain morphology and incorporation of recrystallization heat treatment and martensitic transformation process into previous tube fabrication methods. The modifications were for improving strength anisotropy in hoop and longitudinal directions of cladding tubes. Specimens were irradiated in the experimental fast reactor JOYO at temperatures of 670-807 K to 15.0 dpa maximum. TEM and/or HRTEM observation indicated that nano-scale sized oxide particles were finely distributed in each alloy and were relatively stable under neutron irradiation. Quantitative constitution analyses showed that most of the oxide particles were comprised of yttrium and titanium, and that they were in most case non-stoichiometric. Comparing with past reports on neutron-irradiated ODS steels, the main factors determining oxide stability under neutron irradiation are shown to be irradiation temperature and/or type of oxide

[en] The study of the core structure seen in the halo of Mini-Andromeda 3(M.A.3), which was observed in the Chacaltaya emulsion chamber, is presented. On the assumption that the lateral distribution of darkness of the core is exponential, i.e., D=D0exp(-R/r0), subtraction of D from the halo darkness is performed until the cores are gone. The same quantity on cores obtained in this way are summarized. The analysis is preliminary and is going to be developed

[en] As trends continue toward lighter and more compact equipment, the preparation in thin film form of rare earth magnets with high energy products, by liquid quenching, sputtering and other methods, is being studied. In a previous report, the authors described the effect of the substrate temperature and film deposition rate on the magnetic properties of Nd-Fe-B films prepared by dc diode sputtering and reported that by choosing the film fabrication conditions appropriately, it was possible to obtain films with an anisotropy in the thickness direction. However, the films thus prepared had a small coercivity, and also suffered from poor reproducibility of magnetic characteristics. In the study reported, in consideration of the reproducibility of film properties, the authors used a dc triode sputtering method to prepare films, and investigated the effect of the annealing conditions on the film coercivity

[en] International Linear Collider, ILC, is a future energy-frontier electron-positron machine currently under design by a world-wide collaboration. Utilizing the advantage of linear accelerator, a polarized electron beam plays an essential role for various key physics studies. In addition to the default operation-mode, options are proposed such as polarized positron and polarized-γγ collider mode. In this note, roles of the polarized beams are briefly discussed along the physics expected at ILC

[en] To understand the current situation of internal radiation exposure in the population around the Chernobyl Nuclear Power Plant (CNPP), we examined the ¹³⁷Cs body burden in six residents of Belarus, Ukraine and Russia in 2002 and 2004 using the whole-body counter (WBC) at Nagasaki Univ. (Japan). The data were compared with those of our previous study performed in 1993-1994 using the same method. In 2002 and 2004, peaks of ¹³⁷Cs were detected in two residents from Gomel, which was heavily contaminated by the CNPP accident, one from Minsk (Belarus) and one from Kiev (Ukraine), but another resident from Minsk showed no ¹³⁷Cs peaks. The results of the present study suggests that residents around the CNPP are still exposed to chronic ¹³⁷Cs internal irradiation, probably due to the daily consumption of contaminated domestic foods, but the risk of any disease by the irradiation is quite low. Long-term follow-up of WBC around the CNPP is useful and may contribute to radiation safety regulation together with a reduction of unnecessary radio-phobia for the residents. (authors)