[en] We had being used wire spark chamber (WSC) system to determine particle tracks behind the analyzer magnet in high energy experiments at 1.3 GeV electron synchrotron. But they sometimes caused troubles such as spark noises, consumption of the Krytron pulser and so on. Then we have replaced the WSC system with drift chamber (DC) system for the experiment to measure angular distributions of the differential cross section in proton Compton scattering. These DC's are of two dimensional readout type based on the drift time measurement and the charge division method. In this paper, we will describe the structure, the readout electronics and the results of the beam test of the DC's. (author)

[en] An indicator system for the accelerating energy of INS 1.3 GeV electron synchrotron has been calibrated. The system consists of a search coil mounted in the gap of the synchrotron magnet, a voltage-frequency convertor, a gate controller and a universal counter, and has worked continuously well. The indicated energy has been compared with one deduced from the measurement of bremsstrahlung photon spectrum from the internal target of the synchrotron. We have concluded that the indicator system is operated with a good precision of about +-0.3%. (author)

[en] The observation of the large proton polarization in the process γd → pn stimulated an extensive study of γd reactions in relation to the dibaryon resonance. After the proton polarization measurement at INS, the polarized target asymmetry has been measured and a phenomenological analysis has been done for the process γd → pn. To study the I=1 dibaryon resonance, the measurement of the differential cross section of the process γd → π⁰d is in progress. The present paper describes recent results of these studies on γd reactions. (author)

[en] Latest Super-Kamiokande results of the solar neutrino flux, day/night results, energy spectrum measurements, and oscillation analyses are reported. The observation period spans May 31, 1996 to April 24, 2000, which corresponds to a detector live time of 1117 days. Our preliminary results indicate 1.3σ difference between day and night flux, and the energy spectrum expressed as data/(BP98 SSM) is consistent with a flat spectrum with χ²/D.O.F.=13.7/17. Comparing global-flux oscillation analysis and SK day and night spectra, MSW SMA region, Just-So region and 2-flavor sterile solutions are disfavored at 95% C.L. (author)

[en] The target asymmetry T(theta) in γd → pn has been measured at the photon energies between 300 and 700 MeV. The results show relatively small values. A phenomenological analysis has been made with non-resonant amplitudes calculated in the covariant formalism. Including the dibaryon resonances, the analysis reproduces the data on dσ/d ohm, P(theta), Σ(theta) and T(theta) rather well. (author)

[en] In future linear colliders such as JLC, the beam intensity is limited by the wakefield effect in the main linac. For obtaining the maximum luminosity, therefore, the intensity of positron beam must be as high as that of electron beam. In linear colliders, full intensity beam must be produced at the positron source. In addition, the emittance of the beam should be very small to realize a beam with the dimension in nanometer range at the interaction point, which is necessary to achieve the required luminosity. As the emittance of the positron beam is large at the exit of the source, it is decreased by a damping ring system. However, because of the severe requirement for the damping ring, it is hard to make its admittance large. Therefore, the positron source should produce the beam with the emittance suitable to the admittance of the damping ring system. Thus, the requirements for the positron source for linear colliders are high intensity and low emittance. The method of positron production, the temperature rise of the converter target, the configuration of the positron source, the improvement of the conventional source and the status of research and development are described. (K.I.)

[en] In previous publications the authors have noted remarkable similarities between the reactions of ketone-containing polymers under irradiation both by UV light and γ-rays. They proposed that at least in some cases, this was due to extensive delocalization of the excitation energies created in the aromatic polymer sequences. In photoresist application, it is important to have very high photochemical or radiochemical reactivity in solid polymer films, usually below their glass transition temperatures. The nature of the solid phase restricts the molecular motion available to the molecules and hence places severe restrictions on the types of photochemical reactions which can be carried out efficiently below T_g. In a previous publication they have shown that the presence of copolymerized vinyl naphthalene units effectively quenches the migrating excitons and prevents the occurrence of radiochemical reactions of the ketone traps in both solution and the solid phase. In this paper the authors report studies of the γ-radiolysis of copolymers of styrene and vinyl naphthalene with and without copolymerized ketone traps. It is shown that as in the previous studies, the naphthalene moiety has a strong stabilizing effect on radiation damage in solid polymer samples. A theory is proposed to explain these effects based on the energy of light-induced transitions in the polymer structures

No abstract available

[en] A 111-sec-period X-ray pulsation from Sct X-1 is reported. The pulse profile was found to exhibit double peaks. The x-ray spectrum of Sct X-1 is fitted by a single power-law function with a photon index of about 1.9. Evidence for extremely large absorption (greater than 10 to the 23rd H/sq cm) has been found in the low-energy band and near the iron K-edge. When combined with the previous observations, these data show that the X-ray flux has been variable over more than two orders of magnitude. 15 refs

[en] It is an essential matter for deployment of LMFBR to develop a high suction performance pump which facilitates layout design of the components in the reactor building and reduces the size of the building and accordingly the plant capital cost. Development of such pumps is under way in domestic and overseas countries. A pump nicknamed 'Shrouded Inducer Pump' is an advanced type based upon the design philosophy of 'Non-cavitation erosion' and not 'Non-cavitation'. A series of study on the Shrouded Inducer Pump have been performed. The study indicated that Shrouded Inducer Pump had a high suction performance and could meet the design requirements and be applied to primary pumps for LMFBR. (author)