Reverse Bisimulations on Stable Configuration Structures

The relationships between various equivalences on configuration structures, including interleaving bisimulation (IB), step bisimulation (SB) and hereditary history-preserving (HH) bisimulation, have been investigated by van Glabbeek and Goltz (and later Fecher). Since HH bisimulation may be characterised by the use of reverse as well as forward transitions, it is of interest to investigate forms of IB and SB where both forward and reverse transitions are allowed. We give various characterisations of reverse SB, showing that forward steps do not add extra power. We strengthen Bednarczyk's result that, in the absence of auto-concurrency, reverse IB is as strong as HH bisimulation, by showing that we need only exclude auto-concurrent events at the same depth in the configuration

Neutron-rich nuclei produced at zero degrees in damped collisions induced by a beam of 18O on a 238U target

Cross sections and corresponding momentum distributions have been measured for the first time at zero degrees for the exotic nuclei obtained from a beam of 18O at 8.5 MeV/A impinging on a 1 mg/cm2 238U target. Sizable cross sections were found for the production of exotic species arising from the neutron transfer and proton removal from the projectile. Comparisons of experimental results with calculations based on deep-inelastic reaction models, taking into account the particle evaporation process, indicate that zero degree is a scattering angle at which the differential reaction cross section for production of exotic nuclei is at its maximum. This result is important in view of the new generation of zero degrees spectrometers under construction, such as the S3 separator at GANIL, for example

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

Observation of the second proton alignment in 160^{160}Tm

High-spin states in the doubly odd nucleus 160Tm have been investigated using the $^{130}$Te($^{35}$Cl,5n) reaction and the Euroball $\gamma$-ray detector array. The previously established rotational structures in $^{160}$Tm were extended, leading to the first observation of the second (h$_{11/2})^2$ proton band crossing in this nucleus. This crossing is found to occur at a higher rotational frequency in $^{160}$Tm than in lighter Tm isotopes. This trend resembles that of the first (h$_{11/2})^2$ proton band crossing found in neighboring Er nuclei and is associated with a predicted increase in deformation as a function of neutron number in these isotopes

Spectroscopy of T 3 2 mirror nuclei via two step fragmentation using RISING

Two two step fragmentation reactions were performed using RISING to populate excited states in A 50 mirror nuclei near to the proton drip line, in order to test isospin symmetry. The experiments were designed to observe gamma decays of excited states in the mirror nuclei 53 Ni 53 Mn, which have a large value of total isospin T 3 2 . In the continuing off line analysis, gamma transitions have been observed in 54 Ni indicating that two step fragmentation is a successful technique for spectroscopic investigations of proton rich nuclear systems in this mass region

A distributed implementation of mobile nets as mobile agents

Mobile nets arise as a combination of the name managing techniques of the π-calculus with the representation of concurrency and locality of Petri nets. We propose MAGNETs, a variant of mobile nets that are suitable for an effective, distributed implementation. Such implementation extends an implementation of the Join calculus virtual machine with dynamic reconfiguration features

Spectroscopy of nuclei approaching the proton drip line using a secondary fragmentation technique with the RISING detector array

An experiment utilizing a double fragmentation reaction was performed to study isobaric analogue states in A 50 nuclei approaching the proton dripline. Gamma ray spectroscopy will be used to identify excited states in the neutron deficient nuclei produced in the second fragmentation reaction. Excited state level schemes will be obtained, through comparison with states in their well known mirror partners, along with information on Coulomb effects through measurements of the Coulomb energy differences between isobaric analogue excited states. The validity of isospin symmetry for nuclei approaching the proton drip line can also be investigated and the information gained will aid in testing and improving fp shell model calculations. The analysis of the collected data is at a preliminary stage and current status of this work is reported