H. Bakhru

Transitions between bound states for axially channeled MeV electrons

Abstract Photon lines emitted in the forward direction from 2.0–4.5 MeV electrons channeled along a 〈110〉 axis in a 3400 A Si crystal have been measured and compared with calculations and with previous results from a 12 000 A Si 〈111〉 crystal. Nearly all features agree with predictions based on an isolated string.

Directional correlations of gamma cascades in153Gd

TheEC-decay of153Tb to the levels of153Gd has been studied in singles and coincidence mode using high resolution x-ray andγ-ray Ge(Li) detectors. The results, in general, are in agreement with the recent findings of Tuurnalaet al. showing a very high density of low-spin states in153Gd. The results of theγγ directional correlation experiment using two Ge(Li) detectors together with the I.C.C. data have been used in assigning the spin and parity of 5/2−, 5/2−, 3/2−, 3/2+, 5/2+, 3/2+ and 3/2+ to the 41.6, 109.8, 129.1, 212.0, 303.5, 945.6 and 1102.0 keV states respectively. Multipolarity assignments to majority of theγ-transitions have been made from the I.C.C. data obtained through the knowledge of ourγ-ray intensities and the published conversion-electron intensities. From the multipole characters of theγ-transitions, parity assignments have been made to seven states in153Gd. Our results have been discussed and compared with that of Tuurnalaet al.

Velocity dependence of double inner-shell ionization in vanadium by proton and α-particle impact

Abstract Ratios of double (KL) to single (K) ionization cross sections for proton and α-particle impact on vanadium are measured with velocities V = 0.53 to 1.7 (in units relative to the L-shell electron velocity) and are found to be reproduced by the recipe of McGuire and Richard.

Studies of γ-ray transitions in171Yb

The decay of171Lu(t1/2=8.2 day) to the levels of171Yb has been studied using large volume high resolution Ge(Li), x-ray Ge(Li) and NaI(Tl) detectors.γ-γ coincidence and directional correlation experiments have been performed. Spin-parity of 5/2−, 7/2+, 5/2−, 9/2+, 7/2−, 7/2−, 11/2+, 9/2−, 9/2− and 5/2− have been assigned to the 75.87, 95.26, 122.37, 167.62, 208.00, 230.61, 259.02, 835.21, 948.37 and 1024.87 keV levels respectively. Several new coincidence relations have been observed in the present work. Two newγ-transitions at 141.45 and 821.30 keV observed and two levels at 766 and 944 keV been proposed. Multipolarity assignments have been made for most of theγ-transitions from theK-shell internal conversion coefficients obtained using the presentγ-ray intensities and the published conversion electron intensities. A revised level scheme for171Yb has been proposed and compared with published data.Radioactivity171Lu; measuredT1/2,Eγ,Iγ,γγ coin,γγ (θ), I.C.C.,171Yb deduced levels,J, γ-mixing,π. Enriched targets, Ge(Li) detectors.

Decay of149Gd and directional correlations of gamma cascades in149Eu

The decay of149Gd(9.4d) to the levels of149Eu has been studied using large volume high resolution Ge(Li) and NaI(Tl) detectors,γ-γ coincidence and directional correlation experiments have been performed. Newγ-rays at energies 131.9, 278.6, 384.7, 415.7, 599.2, 726.5, 734.7, 956.4 and 1,231.1 keV in149Eu have been observed. Three new levels in149Eu have been placed at 956.4, 1,082.0 and 1,231.1 keV. Spin-parity assignments have been made to some of the levels in149Eu. Multipolarity assignments have been made for most of the electromagnetic transitions from the conversion coefficients obtained through the knowledge of ourγ-transition intensities and the published conversion-electron intensities. Based on the newγ-transitions observed in the singles and coincidence spectra, a revised level scheme has been proposed for149Eu and compared with previously published level schemes.Radioactivity149Gd; measuredT1/2,Tγ,γγ coin, γγ(θ), I.C.C.,149Eu deduced levels,J,γ-mixing,π. Enriched targets, Ge(Li) detectors.

Levels of33S excited by α-capture reactions

Highly excited levels of33S populated by α-particle capture in29Si have been investigated forEα=1.962 MeV to 4.287 MeV. Excitation curves measured with Ge(Li) and BF3 detectors are reported. More than fifty resonances can be identified with levels in33S. (α, γ) angular distributions measured on five strong resonances have yieldedJπ values 1/2+, 3/2 +, 5/2−, 5/2−, 5/2− and 3/2+ respectively, for theEx=10.054, 10.466, 10.523, 10.721, 10.758 and 10.776 MeV levels in33S. Elastic scattering experiments have been performed and theJπ assignments are found to be consistent with thel-values inferred from the elastic scattering data. Decay schemes from the above33S levels have been proposed. A new level at 9.245 MeV is also suggested and theJπ values for the 4.425 and 2.87 MeV states are shown to be consistent with 7/2+ and 3/2+ assignment, respectively.Nuclear Reactions29Si(α, γ) and29Si(α, α),Eα=1.962-4.287 MeV. Measured relative σ(E). DeducedJπ andEγ of33S levels. New33S level atEx=9.245 MeV. Enriched targets.

Projectile dependence of K-shell ionization in Cl and Ca at 200 keV/amu☆

Abstract Relative K-shell ionization cross sections of Cl and Ca measured with 200 keV/amu singly ionized projectiles of 2 H, 4 He, 12 C, 14 N, 16 O and 20 Ne exhibit features which are adequately described by the combination of binding effect in Coulomb ionization and charge exchange to the empty orbitals of the projectile.