Lifetimes in the ground-state band and the structure of 118Te

Lifetimes of excited states in ¹¹⁸Te have been measured using the Doppler Shift Attenuation (DSA) and Recoil Distance (RD) methods in the ¹⁰⁹Ag(¹³C, p3n) reaction at a beam energy of 54 MeV. Lifetime values of the ground-state band levels with spins I ^π = 2⁺-16⁺ have been obtained. The excitation energies and B(E2) values are interpreted in the framework of a version of IBFM ( IBM + 2qp) with the maximum boson number exceeding its standard value. A satisfactory agreement with experimental level scheme and B(E2) values for the ground-state band is achieved. Received: 7 June 2001 / Accepted: 7 February 2002     

The Decay of130La to levels in130Ba

Theγ-radiation associated with the β⁺ decay of¹³⁰La to levels in¹³⁰Ba is studied. The level scheme is established on the basis of theγ-γ coincidence measurements emploing two Ge(Li) detectors. The available experimental data are compared to collective model calculations withγ-soft P.E.S. andγ-dependent inertial functions. To reproduce levels energyB _ββ value twice as large as other mass parameters is needed.Radioactivity: ¹³⁰La [from¹³⁰Ba(p, n),E _p=10MeV]; measuredE _γ,I _γ,γγ-coin.¹³⁰Ba deduced levels,J, π, logft. Enriched target, Ge(Li) detectors.     

Study of the124Xe and126Xe structure

The level structure of¹²⁴Xe and¹²⁶Xe is studied on the basis ofβ ⁺ decay of¹²⁴Cs and¹²⁶Cs. The Cs isotopes were produced in the Xe(p, n) Cs reactions at a proton energy ofE≈9.5 MeV. Decay schemes are proposed for these nuclei. The available experimental data are compared with the predictions of various models.     

Weighted automata and weighted logics on infinite words

We introduce weighted automata over infinite words with Muller acceptance condition and we show that their behaviors coincide with the semantics of weighted restricted MSO-sentences. Furthermore, we establish an equivalence property of weighted Muller and weighted Büchi automata over certain semirings.     

Description of 111Ru within the Core-Quasiparticle Coupling model

An even-odd isotope of ruthenium, ¹¹¹Ru, is investigated in the framework of the core-quasiparticle coupling model. The energy levels and wave functions of low-lying states are calculated. The only one parameter adjusted to obtain the results in agreement with experimental data is the strength of the core-particle quadrupole-quadrupole interaction. The neighbouring even-even cores, ¹¹⁰Ru and ¹¹²Ru, are described by means of the collective quadrupole plus pairing model with the Bohr Hamiltonian determined fully from a microscopic theory without any adjustable parameter. Results for ¹¹¹Ru are compared with a new set of experimental data obtained recently. An importance of the pairing interaction is confirmed. A remarkable agreement of theoretical results and experimental data is obtained for all eight positive- and negative-parity bands delivered by the newest experiment.PACS:   21.10.Re Collective levels - 21.60.Ev Collective models - 23.20.Lv transitions and level energies - 27.60. + j      

Rigid chains admitting many embeddings

A chain (linearly ordered set) is rigid if it has no non-trivial automorphisms. The construction of dense rigid chains was carried out by Dushnik and Miller for subsets of , and there is a rather different construction of dense rigid chains of cardinality , an uncountable regular cardinal, using stationary sets as `codes', which was adapted by Droste to show the existence of rigid measurable spaces. Here we examine the possibility that, nevertheless, there could be many order-embeddings of the chain, in the sense that the whole chain can be embedded into any interval. In the case of subsets of , an argument involving Baire category is used to modify the original one. For uncountable regular cardinals, a more complicated version of the corresponding argument is used, in which the stationary sets are replaced by sequences of stationary sets, and the chain is built up using a tree. The construction is also adapted to the case of singular cardinals.     

Low-spin structure of 113Ru and 113Rh

The ¹¹³Ru and ¹¹³Rh nuclei, produced in the spontaneous fission of ²⁴⁸Cm and in proton-induced fission of ²³⁸U , were studied by means of prompt gamma spectroscopy using the EUROGAM 2 array of Anti-Compton spectrometers and the IGISOL mass separator, respectively. For the 0.5s isomer, found in ¹¹³Ru in our recent study we propose the 7/2^-[523] configuration. The present data indicate spin and parity 1/2⁺ for the ground state in ¹¹³Ru . This and some new data on the excited levels in ¹¹³Rh allows reinterpretation and a better understanding of the β^- _{} decay scheme of ¹¹³Ru . The properties of ¹¹³Ru were studied in the frame of the Core-Quasiparticle Coupling model, which has well reproduced the experimental data.     

Development of magnetic rotation in light Gd nuclei; study of 142Gd

High-spin states in ¹⁴²Gd have been populated by means of the ⁹⁹Ru(⁴⁸Ti, 2p3n) reaction at 240 MeV and investigated with the γ-spectrometer EUROBALL III and the charged-particle detector array ISIS. The features of four dipole bands have been determined and compared with tilted-axis cranking model calculations indicating that they are magnetic rotational bands. A transition from regular to irregular bands has been found approaching N = 82 demonstrating that this is a general phenomenon in nuclei near a double-shell closure. Received: 9 December 2001 / Accepted: 9 January 2002     

The structure of the odd-A nuclei withA≈130 and the problem ofγ-softness

The negative parity states in the^{123, 125, 131}Cs and the¹³¹La nuclei are described in the framework of the particle-core coupling model. In order to study the problem of gamma softness, the following two core models are used:(1) the rigid triaxial rotor model, and(2) theγ-unstable model withγ-dependent inertial functions. The properties of the odd-A nuclei with rigid and soft cores are compared with the experimental data. The results do not allow to draw a definite conclusion about the softness. When seeking properties which could help to distinguish between soft and rigid nuclei it has been found that some spectroscopic factors for the proton stripping reaction are sensitive to the gamma softness.     

On an extendability problem for measures

We prove a theorem stating a sufficient condition for the existence of an extension of a probability measure, and we use this result to answer a question concerning such extensions in the negative.Finally, I would like to thank Professor M.P. Jerschow for pointing (*) out to me and for an interesting discussion on this topic.