Mass measurements of neutron-deficient nuclides close to A = 80 with a Penning trap

The masses of ^{80, 81, 82, 83}Y, ^{83, 84, 85, 86, 88}Zr and ^{85, 86, 87, 88}Nb have been measured with a typical precision of 7keV by using the Penning trap setup at IGISOL. The mass of ⁸⁴Zr has been measured for the first time. These precise mass measurements have improved S_p and Q_EC values for astrophysically important nuclides.     

Determination of talc in geological samples by infrared spectrometry

Talc is determined by infrared spectrometry in talc ore and mineral mixtures containing clinochlore chlorite, dolomite and magnesite as major minerals. When the Si-O-Si vibration at 668 cm^?1 is used, the calibration graph is linear up to about 0.5 mg of talc. Band overlap from chlorite is corrected by using the ratio of absorbances at 668 and 3620 cm^?1. Talc (?15%) in talc/carbonate/chlorite mixtures and ore was determined with relatively good precision and accuracy (recovery 91.2–97.4%). The sample sizes were 0.5–1 mg for 40–60% talc and 0.5–1.5 mg for 7.5–15% talc. The recoveries were worse (84.0–94.6%) for < 15% talc. The precision for unknown samples of talc ore varied from 1.5 to 4.0% (n=4).     

Coherence-polarization mixing in resonance gratings

We show, using rigorous diffraction theory, that resonance gratings can be used to transfer partial spatial correlation to partial polarization even if the incident light beam is fully polarized. The phenomenon is based on the fact that either of the two orthogonal polarization components can be coupled into the leaky waveguide mode, leading to a strong phase delay, while the other one is reflected without being coupled into the grating. Numerical demonstrations are based on a Gaussian Schell-model beam and a grating analysis performed by rigorous Fourier modal method.     

Time-dependent physical spectra of Gaussian Schell-model pulses

The time-dependent physical spectra introduced by Eberly and Wódkiewicz [J. Opt. Soc. Am. 67 (1977) 1252], observable with a photon-counting detector placed behind a Fabry-Perot filter, are evaluated for a class of temporally partially coherent non-stationary fields known as Gaussian Schell-model plane-wave pulses. Numerical comparisons between source spectra and observed spectra are provided and discussed, and several general features such as initial spectral broadening at the arrival of the pulse and a temporal pulse tail are illustrated. Closed-form approximations are obtained for the time evolution of the observable spectrum by evaluating the leading terms in an appropriate series expansion.     

Penning trap assisted decay spectroscopy of neutron-rich 115Ru

Exotic, neutron-rich ¹¹¹Mo and ¹¹⁵Ru nuclei, produced in proton-induced fission of ²³⁸U target, were separated with the IGISOL mass separator. The separator was coupled to the JYFLTRAP Penning trap to select the ions of a single, desired element out of the isobaric IGISOL beam. Monoisotopic samples of ¹¹⁵Ru and ¹¹¹Mo ions were observed with a microchannel plate detector after the trap or were implanted on a catcher foil for gamma- and beta-ray coincidence spectroscopy. In spite of short data taking time new gamma transitions were identified in the beta decay of very neutron-rich ¹¹⁵Ru.     

Penning-trap-assisted study of 115Ru beta decay

The beta decay of ¹¹⁵Ru has been studied by means of Penning-trap-assisted beta and gamma spectroscopy at the IGISOL facility. The level scheme of ¹¹⁵Rh has been substantially extended and compared with the level systematics of lighter rhodium isotopes. Tentative candidates for three states of the deformed K = 1/2 band have been suggested. The beta-strength distribution of the beta decay of ¹¹⁵Ru differs from the beta decays of ^{111, 113, 113m}Ru isotopes due to non-observation of the 3-quasiparticle states in ¹¹⁵Rh. The decay properties of ¹¹⁵Ru indicate a spin-parity of (3/2⁺ for its beta-decaying ground state. In addition, possible Nilsson states as well as the shape and spin transitions in odd neutron-rich ruthenium isotopes are discussed.     

Precision mass measurements of neutron-rich Y, Nb, Mo, Tc, Ru, Rh, and Pd isotopes

Direct mass measurements with typical uncertainties of 1-10keV have been performed for the first time for ten neutron-rich isotopes ^{102, 103}Y , ¹⁰⁸Nb , ¹¹¹Mo , ^{113, 114}Tc , ¹¹⁶Ru , ¹¹⁹Rh , and ^{121, 122}Pd . The obtained mass data compared with the 2003 atomic-mass evaluation shows systematic overestimation of binding energies far from stability. The relationship between two-neutron separation energies, nuclear structure and shape changes has been investigated by comparing the experimental data with a theoretical calculation based on the Hartree-Fock-Bogoliubov approximation using modern energy density functionals.