[en] This paper presents the principle of the method and the procedure in the concept of high level waste treatment. It also discusses the cost of separation, the experiment, the effect of Cs separation, and the new ''ceram'' properties. (A.L.B.)

[en] Differential cross sections for the (p,⁶Li) reactions for the target nuclei ¹¹B, ¹²C, ¹⁶O and ¹⁹F have been measured at an incident proton energy of 52 MeV using the INS-Tokyo FM cyclotron

[en] Shell-model calculations of the N=27 and 28 nuclei are carried out within the fsub(7/2)sup(n) + fsub(7/2)sup(n-1)(psub(3/2), psub(1/2), fsub(5/2))¹ configurations. Attempts are made to fix effective interactions which are relevant to the model space and can be used for systematic studies of the whole nuclei in this region. The E2 properties of the intruder states in the odd-mass N=27 nuclei are discussed. The calculation shows that there appear some sequences of collective states in ⁵¹Cr and ⁵³Fe, which are characterized by the strongly enhanced E2 transitions. Recent experiments support the calculated feature at least in the lower part of the level sequences. The isovector E2 and M1 transition rates from the analog to low-lying states in ⁵¹V are calculated and compared with the previous calculations and experiments. Role of spin-flip and spin-nonflip transitions are discussed. (author)

[en] Form factors for inelastic electron scattering for the excitation of the 3/2^-, 5/2^-, 9/2^-, 11/2^- and 15/2^- members of the (fsub(7/2))³ configuration in ⁵¹V are studied by considering the effect of configuration mixing in the shell model. The inclusion of the highly excited configurations which does not contribute to the γ-transitions is shown to give rise to significant modifications of the form factors in large momentum transfer regions. Under the assumption of the static central potential as the residual interactions between protons, good agreement with the experimental data on form factors is obtained by the ordinary force as well as smaller effective charges than the bare charge for higher multipole transitions. (Auth.)

[en] An attempt has been made to use the Monte Carlo method for a shell-model calculation of the strength function. It is found that the method works quite well to calculate the Gamow-Teller strength function in ₂₀₈Bi. The widths evaluated from the strength functions are in excellent agreement with those by the Golden Rule in the truncated model space. The spreading width of the Gamow-Teller giant resonance is estimated to be rather than that deduced from the reaction ₂₀₈Pb(p, n)₂₀₈Bi. Interference between particle and hole spreadings reduces the resonance width appreciably. (orig.)

[en] Magnetic dipole excitations in N = 28 isotones ⁴⁸Ca, ⁵⁰Ti, ⁵²Cr and ⁵⁴Fe are studied in terms of shell model which includes configurations with one- and two-particle excitations from fsub(7/2) to psub(3/2), psub(1/2) and fsub(5/2) shell orbits. Distributions of the strength observed in (e, e') and (p, p') experiments are well reproduced. Total strength reduces by about 25% due to the mixing in the 0⁺ ground state, but the calculated strengths are yet 2-3 times greater than the experimental values. Contributions arising from proton excitation and the orbital magnetization are also discussed. (orig.)

[en] The 2ν mode double beta decay of ⁴⁸Ca is studied in detail, particularly in connection with validity of the closure approximation. In an extensive shell-model calculation, nuclear matrix elements for low-lying and high-lying intermediate states have opposite signs. It is therefore indicated that a very small value has to be adopted for the average excitation energy, if one utilizes the closure approximation. (orig.)

[en] Magnetic dipole excitation of N=28 isotones - ⁴⁸Ca, ⁵⁰Ti, ⁵²Cr, ⁵⁴Fe and ⁵¹V - is studied in terms of the shell model by assuming fsub(7/2)sup(n-m)(psub(3/2)psub(1/2)fsub(5/2))sup(m) configurations with m=0, 1 and 2 on an inert ⁴⁰Ca core. Strength distributions observed in (e,e') and (p,p') experiments are fairly well reproduced. Interference of proton and neutron excitations enhances B(M1) values around Esub(x)=10 MeV and reduces those of low-lying states. The strength for T=T₀+1 states substantially increases when orbital magnetization is not taken into account, whereas no appreciable consequences can be seen for T=T₀ states. In comparison with single-particle model predictions with m=0, about 20-30% reduction of the total strength is obtained due to ground-state configuration mixing. It is shown that the isoscalar spin component is reduced as well as the isovector one. However, the theoretical total strength is still much larger than experimental values, and coupling with high-lying configurations and possible delta-hole excitation might be required in order to account for the discrepancy. In an odd-mass nucleus ⁵¹V, the ground-state transition strength is distributed continuously over a wide energy range, being very strongly fragmented. (orig.)

[en] The Gamow-Teller giant resonance observed in the ²⁰⁸Pb(p, n)²⁰⁸Bi reaction is studied in terms of shell model. 2p-2h excitations are taken into the model space in addition to 1p-1h on the doubly closed ²⁰⁸Pb core. The giant resonance is well reproduced and the Gamow-Teller strength is highly fragmented among a number of 1⁺ states in the resonance region. (orig.)

[en] The low-lying levels of the 1fsub(7/2) nuclei have been studied in the framework of shell model with effective interactions in the fsub(7/2)sup(n) and fsub(7/2)sup(n-1) P/3 configurations. Good agreement with experiments is obtained and the discrepancies inevitable when pure fsub(7/2) model is used are resolved