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We developed an electroformed copper lining for RF cavities. The pure copper lining with mirror-finish surface was produced by electropolishing the machined surface of an electroformed copper layer obtained from an acid copper sulfate bath containing no organic additives. The copper lining was successfully applied to large RF cavities for the Japan Hadron Facility being constructed by the High Energy Accelerator Research Organization. Dramatic rise in accelerating performance was achieved by this new lining.

Self-field loss of Ag/Bi-2223 tape conductors cooled by using the GM cryocooler in the temperature range of 60–100 K was studied in the conditions of various frequencies (10–500 Hz) of AC transport current. Self-field loss per cycle and per length divided by a square of critical current, Ic2, decreased with increase of the frequency and with decrease of temperature unlike Norris' equation. Especially, the loss reduction ratio by frequency change decreased with increase in temperature. To confirm difference in loss dependencies between the calculated and the experimental results, we also achieved the numerical analysis based on Maxwell's equations using a finite difference method. The analysis results were mostly in agreement with the experimental results.

Tohoku Electric Power Company and Tohoku University are cooperatively studying the effective use of a new monitoring .system using GPS (Global Positioning System). This system ensures achieving synchronous measurements at multiple remote electric supply station by using the time stamp facilities of GPS. First, this paper introduces briefly "Synchronous Monitoring System at multiple locations applying GPS techniques". Following section summarizes features of power flow fluctuation gotten by the developed monitoring system. The authors suggest some visual methodologies todisplay the features of the acquired data, and conduct a feasibility study on extracting hidden signals to identify insecure conditions in the power system.

QED processes up to O(α 4 ) have been studied at center-of-mass energies between 50 and 57 GeV using the AMY detector at TRISTAN. A possible substructure of the electron and muon is investigated in terms of chiral invariant contact interactions and also in terms of excited lepton production. The differential cross section data for e + e − →e + e − are consistent with the standard model at a confidence level of only 3.5%. From the absence of excited lepton production, we establish new upper limits on the coupling to excited electrons of mass up to 56 GeV/ c 2 and on the coupling to excited muons of mass up to 52 GeV/ c 2 .

The total cross section for e + e − annihilation into hadrons has been measured for CM energies ranging from 50 to 57 GeV. We fit the predictions of the standard model to these measurements and those at lower energies. The mass of the Z 0 boson, M Z , and the QCD scale parameter, Λ MS , are derived from the fit. The results are M Z =88.6 −1.8 +2.0 GeV/ c 2 , and Λ MS =0.15 −0.11 +0.16 GeV .

Identification of relativistic charged particles by means of fine sampling dE/dX measurements with a longitudinal drift chamber has been studied. Using a fast-sampling ADC (25 MHz), dE/dX was measured in a 1.4 mm gas thickness over an electron drift space of 51 mm. For the simulated 1 m long tracks of pions and electrons of 500 MeV/c, a particle separation of 10σ−12σ has been obtained, where σ is the r.m.s. resolution of the dE/dX measurement. This result with fine sampling is better by a factor of 1.7 compared to the dE/dX measurement with 21 mm sampling thickness. Further improvement achievable by reducing the correlation between neighbouring samples and simplification of electronics by use of the δ-ray clipping method are also discussed.

Differential cross sections of proton Compton scattering have been measured in the energy range between 400 MeV and 1050 MeV at C.M.S. angles of 150° and 160°. The recoil proton was detected with a magnetic spectrometer using multi-wire proportional chambers and multi-wire spark chambers. The scattered photon was detected with a lead glass Cerenkov counter of the total absorptive type with two layers of multi-wire proportional chambers which measured the horizontal and vertical positions of the scattered photon. The proton Compton scattering was differentiated from the background of the π 0 photoproduction events with the use of angular correlations between the recoil proton and the scattered photon. The cross-section data show the clear second resonance peak at E γ = 750 MeV and a bump around E γ = 925 MeV at both angles. Also the angular distributions show the backward peak in the energy range between 700 MeV and 950 MeV. The data are compared with theoretical calculations based on an isobar model with some phases for the resonances. In this calculation, the proton Compton data were fitted varying the photocouplings of the nucleon resonances around the bump and the phases below the third resonances as free parameters. The calculation reproduced the angular distribution of differential cross sections well. However, it was inevitable that we use large photocouplings of P 33 (1600) in order to fit the bump.

Measurements of the differential cross sections for e + e − →μ + μ − and e + e − →τ + τ − at values of s from 52 to 57 GeV are reported. The forward-backward asymmetries and the total cross sections for these reactions are found to be in agreement with predictions of the standard model of the electro-weak interactions. These measurements are used to extract values of the weak coupling constant g v e g v l and g A e g A l , where l = μ or τ .