No abstract available

[en] Negative muon lifetimes have been measured in 48 elements including four pairs of separated isotope targets (⁶Li, (⁶Li, ⁷Li, ¹⁰B, ¹¹B, ¹²C, ¹³C, ¹⁶O, ¹⁸O). The experimental set-up and electronics logic were checked against the positive muon lifetime, which was measured to be 2197.0 ± 0.077 ns, in good agreement with the accepted value of 2197.120 ± 0.077 ns. Muons were produced by the backward decay of pions which were provided by the M20 beam channel at TRIUMF. The negative muon lifetimes were measured for all light elements except H and He. An improved accuracy has been achieved in Be, H, O,F, Ha, Cl, and K, and new measurements were peformed for ¹³C, ¹⁸O, Dy and Er. Strong isotope effects were observed in Li, B, and O, but there was no isotope effect in C. Our results in ⁶Li and ⁷Li were in good agreement with the predicted values by Lodder and Jonker. Our measurements confirm that the even-odd effect in heavy nuclei is not strong and the increase of the odd-Z capture rates is smaller than that expected from the quenching of the Cabitbo angle in large magnetic fields. The negative muon beam was also stopped in 23 metallic oxides in order to measure the atomic capture ratios. The number of muons captured by each element was deduced by lifetime analysis. Our result reproduced the periodic dependence and agreed well with earlier x-ray measurements. The results however are of higher accuracy and are liable to very different systematic errors, which gives added confidence to the overall situation

[en] This paper reports that more than any other industrial country, Japan is staking its industrial future on nuclear power. Its 39 commercial reactors generate more than 31,000 megawatts of electricity-supplying more than a quarter of Japan's electricity. By early in the next century, reactors now planned or under construction will bring that figure to near 45,000 megawatts, and half of Japan's electricity will have nuclear origin. These reactors perform as reliably as any in the world: since 1982 Japanese nuclear plants have, on average, operated at above 70 percent of their maximum capacity. Such success with nuclear power is hardly surprising for a technologically advanced country that has virtually no domestic coal or oil. Nuclear power has been Japan's ticket to energy independence. But these glowing statistics may be obscured by a growing cloud. Not only have recent accidents marred a previously excellent safety record and diminished public confidence, but the Japanese nuclear program's guiding vision-the establishment of an indigenous nuclear power supply using breeder reactors and recycled plutonium fuel-is threatened. Many countries -including the United States-made breeders a key part of their nuclear energy strategy in the early 1970s. But most nations have scaled back their breeder plans, for two reasons. First, the fuel they breed in plutonium, which can be directly used to make a nuclear bomb. Second, the economics that once made breeders seem a prudent energy strategy have changed dramatically. With uranium supplies ample and demand slack, the material's cost has dropped and its availability risen; meanwhile, the cost of extracting plutonium from spent fuel has skyrocketed

[en] Emittance growth by synchrobetatron resonance is estimated for the 6 GeV booster of the Advanced Hadron Facility. It is shown that the emittance growth is modest both for horizontal and vertical betatron motions if we avoid only the m = 1 resonance where the resonance condition is ν/sub x/ - mν/sub s/ = integer

[en] The aim of this work is to determine the effect of irradiation on the alteration of high level nuclear waste forms matrices. The matrices investigated are UO₂ to simulate the spent fuel, the hollandite for the specific conditioning of Cs, and the inactive glass SON68 representing the nuclear glass R7T7) The alpha irradiation experiments on UO₂ colloids in aqueous carbonate media have enabled to distinguish between the oxidation of UO₂ matrix as initial and dissolution as subsequent step. The simultaneous presence of carbonate and H₂O₂ (product resulting from water radiolysis) increased the dissolution rate of UO₂ to its maximum value governed by the oxidation rate. ii) The study of hollandite alteration under gamma irradiation confirmed the good retention capacity for Cs and Ba. Gamma irradiation had brought only a little influence on releasing of Cs and Ba in solution. Electronic irradiation had conducted to the amorphization of the hollandite only for a dose 1000 times higher than the auto-induced dose of Ba over millions of years. iii) The experiences of glass irradiation under alpha beam and of helium implantation in the glass SON68 were analyzed by positon annihilation spectroscopy. No effect has been observed on the solid surface for an irradiation dose equal to 1000 years of storage. (author)

[en] The structure of giant resonance states are studied with the aid of sum rules. The sum rule for the nuclear current yields an irrotational velocity field for the doorway states. The relationship between zero-range forces and separable forces in the random phase approximation is derived using a sum rule for transition densities. Tomanaga theory provides us with the reason why zero-range forces and the Q-Q force predict the same excitation energy for the quadrupole mode. This is because both the effective forces do not yield the restoring force. The restoring force coming from the increasing of the kinetic energy well reproduces the mass number dependence of the experimental values of the excitation energy. Tomanaga theory explains also the narrow damping width of the collective quadrupole state as a result that its collective momentum commutes with zero-range forces

No abstract available

[en] In this paper theories of synchro-betatron resonances are reviewed. The emphasis is on recent works with which I have been more or less concerned. Only single-beam effects are treated

[en] The effect of high temperature annealing on ErBa₂Cu₃O_y (ErBCO) films grown by liquid-phase epitaxy was investigated. As-grown ErBCO films with T_c (onset) of 84 K showed slight increase to 89 K by long-time O₂ annealing at 400-500 deg. C for 300 h. High temperature annealing at 800 deg. C with an initial partial oxygen pressure of 0.01 atm increased the T_c (onset) of as-grown ErBCO films from 84 to 90 K and decreased the residual resistivity to zero. High temperature annealing also improved the superconductive properties of ErBCO films annealed at 500 deg. C for 24 h in O₂. The T_c (zero) and transition width of the O₂ annealed ErBCO films increased from 82 and 10 to 91 and 2 K, respectively

[en] L-band niobium coated copper cavities have been developed for the application to TeV linear colliders and FEL drivers. Single cell copper cavities were made by electroforming. Niobium films were deposited by the RF magnetron sputtering method. After the sputtering conditions were optimized, the 1.5 GHz single cell coated cavity attained a Q₀ of 2 x 10⁹ at 1.8 K at low fields. The 1.3 GHz single cell coated cavity has achieved a maximum accelerating field gradient of more than 10 MV/m without any field emission or thermal instability. (author)