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One of the most frequent types of intraocular melanoma in adults is choroidal uveal melanoma. The most commonly used forms of radiation therapy are ophthalmic plaque brachytherapy and charged particle external radiation therapy. In the absence of adequate facilities for brachytherapy and proton therapy, electron therapy would be an efficient radiation therapy technique for treating eye melanomas. In the present work, the Monte Carlo code MCNPX 2.6.0 was used to calculate the dose distribution to substructures of the eye in electron therapy of three common choroidal tumors. The simulations were performed for 6 electron beams with nominal energies between 5 MeV and 10 MeV and also for 10 incidence angles. To identify suitable treatment plans, the tumor-to-sensitive zone dose ratios were estimated. Moreover, the equivalent doses delivered to healthy substructures of the eye were also calculated. The results indicate that for the treatment of tumors located at the posterior part of the eye, an electron beam with energy of 10 MeV and incident angle of 45° relative to the eye axis provides the best tumor coverage while optimally sparing other eye substructures. In addition, for tumors positioned on the upper and lower parts of the vitreous, electron beams with energy of 10 MeV, an azimuthal angle of 270°, and polar incident angles of 90° and 105°, respectively, lead to appropriate dose delivery.

High spin states in the odd–odd nucleus 122Cs have been studied by in-beam γ-ray spectroscopy with a 107Ag(19F,1p3n) fusion-evaporation reaction at a beam energy of 85 MeV. A previously known πh11/2 ⊗ νh11/2 yrast band was confirmed and its spin I was re-examined. A ΔI = 2 band was identified, which together with another known ΔI = 2 band forms a side band of the πh11/2 ⊗ νh11/2 yrast band. The two observed πh11/2 ⊗ νh11/2 bands are proposed as a pair of chiral doublet bands in 122Cs based on a systematic comparison with those in the neighbouring odd–odd Cs isotopes, as well as the relativistic mean field and the triaxial particle-rotor-model calculations.

High spin levels of the very neutron-rich ${}^{152}$Ce have been investigated by measuring the prompt $\ensuremath{\gamma}$ rays in the spontaneous fission of ${}^{252}$Cf. The yrast band is confirmed and a new side-band has been identified. The side-band is tentatively assigned with negative parity and an octupole band structure with $s=+1$ in ${}^{152}$Ce has been proposed. Based on the theoretical calculations and systematic comparisons, the characteristics of the octupole correlations have been discussed.

High-spin states in 122Ba have been investigated in the 107Ag(19F, 4n) reaction by in-beam γ-ray spectroscopic methods. The ground-state band has been observed with spin up to 20 and a negative-parity band is identified with spin state up to 19. A band-crossing in the yrast band is observed at a rotational frequency of ω≈ 0.36 MeV and, in accordance with cranked shell model calculations, is interpreted as arising from the alignment of two h11/2 protons. Strong E1 transitions between the negative-parity and the yrast bands have been observed, which are proposed as possible evidence for octupole correlations.

Levels in the neutron-rich 104Mo nucleus have been investigated by observing prompt γ-rays from the spontaneous fission of 252Cf with the Gammasphere detector array. The ground-state band, the one-phone and the two-phone γ-vibrational bands as well as a quasiparticle band have been confirmed and expanded with spin up to 14. Other two side bands probably built on new quasiparticle states are identified. The possible configurations for the quasiparticle bands are discussed. Two of the quasiparticle bands show larger moments of inertia and may have pair-free characteristics. The levels of the ground-state band, the one-phonon γ-band and the two-phonon γ-band calculated from a general collective model are in close agreement with the experimental data. PACS: 21. 10. Re, 23. 20. Lv, 27. 60. +j, 25. 85. Ca

High spin states in 137Ce have been studied by using the heavy-ion induced reaction 124Sn(18O, 5n) carried out at China Institute of Atomic Energy. Partial level scheme with spin up to (43/2-), including a high spin collective rotational band observed for the first time, has been established. The collective band shows the properties similar to those oblate bands with ? ~ -60? in neighboring nuclei and probably originates from the five quasi-particle configuration ?s1/2 ? [?h11/2]2 ? ?g7/2 ? ?h11/2. The characteristics of this oblate band have been discussed.

High spin states in neutron-rich odd-N 145Ba nucleus have been investigated from study of prompt γ-rays in spontaneous fission of 252Cf. The alternating parity bands are identified indicating octupole deformation with simplex quantum number s = -i. The ground state band shows signature splitting and inversion at low spin. These collective band structures exhibit the competition and co-existence between symmetric and asymmetric shapes.

High spin states in 138Ce have been investigated following heavy-ion induced reactions carried out at the China Institute of Atomic Energy, Beijing. Two collective rotational bands were established for the first time. These two bands show oblate deformation with γ = -60° and probably originate from the four quasiparticle configurations πg7/2 ⊗ πh11/2 ⊗ νh11/2 ⊗ νd3/2 and πg7/2 ⊗ πh11/2 ⊗ [νh11/2]2, respectively. These oblate bands exhibit strong M 1 transitions, no signature splitting and different moments of inertia from those of prolate bands.

The levels in neutron-rich odd-A 107,109Ru nuclei have been investigated by using γ-γ- and γ-γ-γ-coincidence studies of the prompt γ-rays from the spontaneous fission of 252Cf. The ground state bands and the negative parity bands are identified and expanded in both nuclei. Triaxial rotor plus particle model calculations indicate the ground state bands originate from ν(d5/2 + g7/2) quasiparticle configurations and the negative parity bands are from νh11/2 orbital.

New transitions and levels in $^{148}\mathrm{Ce}$ have been observed in a $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ coincidence study from the spontaneous fission of $^{252}\mathrm{Cf}$ with Gammasphere detector array. The ground band has been extended up to ${I}^{\ensuremath{\pi}}={22}^{+}$, and side bands are extended with $\ensuremath{\Delta}I=2$ stretched transitions and $\ensuremath{\Delta}I=1$ crossing transitions. The observed level scheme is interpreted in terms of possible octupole correlations. Two sets of interwined positive- and negative- parity bands with the simplex quantum numbers $s=\ifmmode\pm\else\textpm\fi{}1$ are suggested. The results of $B(E1)/B(E2)$ branching ratios indicate that the octupole correlations in $^{148}\mathrm{Ce}$ are strong.

Levels in the neutron-rich, odd-mass ${}^{107}\mathrm{Ru}$ nucleus have been reinvestigated with Gammasphere by measuring high-fold, prompt coincidence events following spontaneous fission of ${}^{252}\mathrm{Cf}.$ The ground state band has been extended up to $\frac{27}{2}\ensuremath{\Elzxh}.$ The structure associated with the ${h}_{11/2}$ excitation has been confirmed and extended to higher spin. The ${h}_{11/2}$ band head has been established to lie at 301.8 keV. These results clear up differences between our earlier work and results from another experiment published recently. A new collective band based on a ${9/2}^{\ensuremath{-}}$ level has been identified for the first time. Some distinct features of the level scheme are discussed.

High-spin structures in the neutron-rich nuclei ${}^{145}\mathrm{Ce}$ and ${}^{147}\mathrm{Ce}$ produced in the spontaneous fission of ${}^{252}\mathrm{Cf}$ have been investigated by prompt $\ensuremath{\gamma}$-ray spectroscopy. A collective band structure in ${}^{145}\mathrm{Ce}$ is identified. Several sidebands along with the new high-spin states in ${}^{147}\mathrm{Ce}$ are also identified. Particle-plus-rotor model calculations indicate that the yrast bands in ${}^{145}\mathrm{Ce}$ and ${}^{147}\mathrm{Ce}$ most probably originate from coupling of the $\ensuremath{\nu}{i}_{13/2}$ orbital to the ground states of ${}^{144}\mathrm{Ce}$ and ${}^{146}\mathrm{Ce}.$ The ground state configurations of ${}^{145,147}\mathrm{Ce}$ are $(\ensuremath{\nu}{h}_{9/2}+\ensuremath{\nu}{f}_{7/2})$ and $\ensuremath{\nu}{h}_{9/2},$ respectively.

High spin states in neutron-rich odd-{ital Z} {sup 143,145}Ba nuclei have been investigated from the study of prompt {gamma} rays in the spontaneous fission of {sup 252}Cf by using {gamma}-{gamma}- and {gamma}-{gamma}-{gamma}- coincidence techniques. Alternating parity bands are identified for the first time in {sup 145}Ba and extended in {sup 143}Ba. A new side band, with equal, constant dynamic, and kinetic moments of inertia equal to the rigid body value, as found in superdeformed bands, is discovered in {sup 145}Ba. Enhanced E1 transitions between the negative- and positive-parity bands in these nuclei give evidence for strong octupole deformation in {sup 143}Ba and in {sup 145}Ba. These collective bands show competition and coexistence between symmetric and asymmetric shapes in {sup 145}Ba. Evidence is found for crossing M1 and E1 transitions between the s=+i and s={minus}i doublets in {sup 143}Ba. {copyright} {ital 1999} {ital The American Physical Society}