[en] In normal metals, macroscopic properties are understood using the concept of quasiparticles. In the cuprate high-temperature superconductors, the metallic state above the highest transition temperature is anomalous and is known as the “strange metal.” We studied this state using angle-resolved photoemission spectroscopy. With increasing doping across a temperature-independent critical value p_c~ 0.19, we observed that near the Brillouin zone boundary, the strange metal, characterized by an incoherent spectral function, abruptly reconstructs into a more conventional metal with quasiparticles. Above the temperature of superconducting fluctuations, we found that the pseudogap also discontinuously collapses at the very same value of p_c. These observations suggest that the incoherent strange metal is a distinct state and a prerequisite for the pseudogap; such findings are incompatible with existing pseudogap quantum critical point scenarios.

[en] An approach how and what to discuss the decommissioning of large accelerator facilities has been overviewed through a case study on Stanford Linear Accelerator Center (SLAC) in USA, which is also under discussion in Japan. SLAC has its own framework on radioactive waste management, however it is still involved in difficulties about the treatment of large amount of low-level radioactivated materials, such as shielding blocks or soil surrounding the underground accelerator. Introduction of disposition criterion of solid material was deferred by US regulatory authority. SLAC is also focusing on the environmental protection using Environmental Restoration Project due to United States Environmental Protection Agency (USEPA). Remedies for the circumstance water or land which are affected by the SLAC's past operations are started. Every kind of pollution including radioactive contaminations are targets of remedies. It means they address the inclusive management of various risks, such as chemical hazardous risk and radiological consequence risk. It is helpful for other accelerator facilities over the world which program decommissioning. (author)

[en] International Commission on Radiological Protection (ICRP) recommended the revision of the exposure dose evaluation system, in '1990 Recommendation of the ICRP, Adopted by the Commission on Nov. 1990' (Publication 60). On the basis of this recommendation, Japan revised the regulations about dose evaluation system and took effect them on and after April 2001. The conversion coefficients for neutron dose evaluation was also revised. Neutron dose is popularly measured with a particular instrument, called REM Counter. However, the revision of the conversion coefficients can cause the REM Counter's response inutile. So, utilizing the technique about the simulation of radiation detector's response, the response of REM counter was evaluated and the compatibility to the new dose evaluation system was discussed. The response of the REM counter may not cause serious problem in utilization as usual, even though it may undervalue the neutron dose a little. Additionally, this underestimation can be resolved by proper calibration. (author)

No abstract available

[en] An investigation on the performance of various dosimeters to be used for individual monitoring at the O-arai Engineering Center (OEC) was executed. The present TLD system was compared with recently produced dosimeters, such as OSL, Glass dosimeter, EPD and SSTD. The practical use of these dosimeters was also taken into account. There were no problems for any of the dosimeters for γ-ray individual monitoring. The OSL and glass dosimeters, which have good characteristics for γ-ray, can be used in various radiation environments without correction. On the other hand, the conversion factor is needed for low-energy γ-ray dosimetry when using EPD or TLD. None of the individual neutron dosimeter's responses relative to the neutron dose are adequate. Respective dose corrections according to the field conditions should be applied to the dosimeter outputs. The directional dependence of the relative response of EPD and SSTD are significant, and attention should be paid to the directional distribution of incident neutrons when using EPD or SSTD. The operational characteristics of each dosimeter were discussed, such as batch processing availability, robustness, fading characteristic, and reusability. As the result of the investigation, EPD was found to be the best γ-ray individual dosimeter for OEC applications, because of its flexibility in operation. On the other hand, the best neutron dosimeter for OEC is the TLD because of the low directional dependence of response. (author)

No abstract available

[en] A method of measuring the impurities of nuclear material samples using a pyrochemical multiple counter has been developed by Langner and others. The pyrochemical multiple counter consists of many thermal neutron detecting tubes arranged in four concentric rings within a polyethylene moderator, and a nuclear material sample is set in the center of the counter. Each ring of tubes has a different energy response owing to the difference of the effective moderator thickness, and each ring gives a different count with the same sample. The stopping power of the moderator varies with the incident neutron energy, and the differences in the counts from the various rings are related to the energy. The average energy of neutrons from a nuclear material sample varies with the impurities of the sample, therefore it is expected that the ratios of counts from the four rings will indicate the impurity concentration of the sample, and this was confirmed by experimentation. Langner and others used a multiple counter, but this method can be applied to two detectors which possess different energy responses and are in the same condition. In this paper, which investigates the applicability of this method to a fast-thermal neutron simultaneous counting detector which possesses two kinds of energy response in a single detector, we present the results of an experimental examination of the energy response of this detector to neutrons at energy of several MeV (J.P.N.)

[en] We present the case of a patient who was diagnosed preoperatively as a case of eosinophilic chronic rhinosinusitis with supra agger frontal cell (SAFC) cyst. In fact, there was no cyst, but rather bone thinning of the anterior cranial floor caused by nasal polyps. Therefore, the cyst wall was perforated, but it was actually the dural membrane, and spinal fluid leakage occurred. Intraoperative MRI was used to minimize complications. The dura was repaired using a free mucosal flap and the postoperative course was satisfactory. Even polyps, such as in case of eosinophilic chronic rhinosinusitis, can cause thinning and loss of bone in the skull base, and intraoperative MRI, which can confirm dural membrane damage and anatomic location, is useful if such a finding is present. (author)

[en] It was necessary to clarify closing mechanism of closed fatigue crack and evaluate such in high precision so as to ensure reliability of nuclear reactor and airplane. Three dimensional crack growth monitoring of closed crack depth distribution in the length direction and change in open and closed region within a crack with crack extension was conducted for closed fatigue crack created at compact tension specimen made of aluminium alloy A 7075 using such developed methods of subharmonic phased array for crack evaluation (SPACE), imaging method for closed cracks using nonlinear response of elastic waves at subharmonic frequency, and also load difference phased array (LPDA), nonlinear ultrasonic imaging method for closed cracks using subtraction of responses at different external loads. Results showed closed region within a crack was different in surface and inside and also open and closed region changed with crack extension in the three-dimensional way. (T. Tanaka)

[en] Evaluation of annual average of radionuclide concentration in surface air obtained from atmospheric dispersion factor is intended to determine a public dose as a primary source for the safety analysis of nuclear facilities in normal operation. Oarai Research and Development Center (ORDC) of the Japan Atomic Energy Agency have used fixed 5-year meteorological statistics for derivation of atmospheric dispersion factors as average conditions. To show that the meteorological statistics for any 5-year period could be used as representative data for evaluation of average conditions, annual average (1-year average) and 5-year average of evaluated radionuclide concentrations derived from the meteorological data observed over a 20-year period (1991-2010) at ORDC were analyzed. Fluctuations of evaluated radionuclide concentrations of any 5-year averages were smaller than those of 1-year averages. Further, any 5-year averages were sufficiently convergent to 20-year average. Because any 5-year averages contained no rejections by the F-test (5% significance level), they were not statistically different to the rest of 20 years data set, instead that some of 1-year averages could be rejected. It means that any 5-year averages of radionuclide concentration evaluations are well representative for the safety analysis of normal operation of the nuclear facilities in ORDC. (author)