Effect of nuclear periphery on nucleon transfer in peripheral collisions

A comparison of experimental heavy residue cross sections from the reactions 86Kr+64Ni,112,124Sn with the model of deep-inelastic transfer (DIT) is carried out. A modified expression for nucleon transfer probabilities is used at non-overlapping projectile-target configurations, introducing a dependence on isospin asymmetry at the nuclear periphery. The experimental yields of neutron-rich nuclei close to the projectile are reproduced better and the trend deviating from the bulk isospin equilibration is explained. For the neutron-rich products further from the projectile, originating from hot quasiprojectiles, the statistical multifragmentation model reproduces the mass distributions better than the model of sequential binary decay. In the reaction with proton-rich target 112Sn the nucleon exchange appears to depend on isospin asymmetry of nuclear periphery only when surface separation is larger than 0.8 fm due to the stronger Coulomb interaction at more compact di-nuclear configuration.Comment: LaTeX, 13 pages, 7 figures, to appear in Nuclear Physics

Isoscaling in Peripheral Nuclear Collisions around the Fermi Energy and a Signal of Chemical Separation from its Excitation Energy Dependence

The isoscaling is investigated using the fragment yield data from fully reconstructed quasi-projectiles observed in peripheral collisions of 28Si with 124,112Sn at projectile energies 30 and 50 MeV/nucleon. The excitation energy dependence of the isoscaling parameter beta_prime is observed which is independent of beam energy. For a given quasi-projectile produced in reactions with different targets no isoscaling is observed. The isoscaling thus reflects the level of N/Z-equilibration in reactions with different targets represented by the initial quasi-projectile samples. The excitation energy dependence of the isoscaling parameter beta_prime, corrected for the trivial 1/T temperature dependence, does not follow the trend of the homogeneous system above 4 MeV/nucleon thus possibly signaling the onset of separation into isospin asymmetric dilute and isospin symmetric dense phase.Comment: 4 pages, 4 figures, RevTeX, to appear in Physical Review

Heavy Residue Isoscaling as a Probe of the Symmetry Energy of Hot Fragments

The isoscaling properties of isotopically resolved projectile residues from peripheral collisions of 86Kr (25 MeV/nucleon), 64Ni (25 MeV/nucleon) and 136Xe (20 MeV/nucleon) beams on various target pairs are employed to probe the symmetry energy coefficient of the nuclear binding energy. The present study focuses on heavy projectile fragments produced in peripheral and semiperipheral collisions near the onset of multifragment emission E*/A = 2-3 MeV). For these fragments, the measured average velocities are used to extract excitation energies. The excitation energies, in turn, are used to estimate the temperatures of the fragmenting quasiprojectiles in the framework the Fermi gas model. The isoscaling analysis of the fragment yields provided the isoscaling parameters "alpha" which, in combination with temperatures and isospin asymmetries provided the symmetry energy coefficient of the nuclear binding energy of the hot fragmenting quasiprojectiles. The extracted values of the symmetry energy coefficient at this excitation energy range (2-3 MeV/nucleon) are lower than the typical liquid-drop model value ~25 MeV corresponding to ground-state nuclei and show a monotonic decrease with increasing excitation energy. This result is of importance in the formation of hot nuclei in heavy-ion reactions and in hot stellar environments such as supernova.Comment: 11 pages, 9 figures, submitted to Phys. Rev.

Production of cold fragments in nucleus-nucleus collisions in the Fermi-energy domain

The reaction mechanism of nucleus-nucleus collisions at projectile energies around the Fermi energy is investigated with emphasis on the production of fragmentation-like residues. The results of simulations are compared to experimental mass distributions of elements with Z = 21 - 29 observed in the reactions 86Kr+124,112Sn at 25 AMeV. The model of incomplete fusion is modified and a component of excitation energy of the cold fragment dependent on isospin asymmetry is introduced. The modifications in the model of incomplete fusion appear consistent with both overall model framework and available experimental data. A prediction is provided for the production of very neutron-rich nuclei using a secondary beam of 132Sn where e.g. the reaction 132Sn+238U at 28 AMeV appears as a possible alternative to the use of fragmentation reactions at higher energies.Comment: LaTeX, 15 pages, 5 figures, minor modifications, accepted for publication in Nuclear Physics

Heavy Residues with A<90 in the Asymmetric Reaction of 20 AMeV 124Sn+27Al as a Sensitive Probe of the Onset of Multifragmentation

The cross sections and velocity distributions of heavy residues from the reaction of 20 AMeV 124Sn + 27Al have been measured at forward angles using the MARS recoil separator at Texas A&M in a wide mass range. A consistent overall description of the measured cross sections and velocity distributions was achieved using a model calculation employing the concept of deep-inelastic transfer for the primary stage of peripheral collisions, pre-equilibrium emission and incomplete fusion for the primary stage of more violent central collisions and the statistical model of multifragmentation (SMM code) for the deexcitation stage. An alternative calculation employing the sequential binary decay (GEMINI code) could not reproduce the observed yields of the residues from violent collisions (A<90) due to different kinematic properties. The success of SMM demonstrates that the heavy residues originate from events where a competition of thermally equilibrated fragment partitions takes place rather than a sequence of binary decays.Comment: 17 pages, 15 figures, LaTeX, to appear in NP

An Offset Cancelation Technique for Latch Type Sense Amplifiers

An offset compensation technique for a latch type sense amplifier is proposed in this paper. The proposed scheme is based on the recalibration of the charging/discharging current of the critical nodes which are affected by the device mismatches. The circuit has been designed in a 65 nm CMOS technology with 1.2 V core transistors. The auto-calibration procedure is fully digital. Simulation results are given verifying the operation for sampling a 5 Gb/s signal dissipating only 360 uW

Isoscaling Studies of Fission - a Sensitive Probe into the Dynamics of Scission

The fragment yield ratios were investigated in the fission of 238,233U targets induced by 14 MeV neutrons. The isoscaling behavior was typically observed for the isotopic chains of fragments ranging from the proton-rich to the most neutron-rich ones. The observed high sensitivity of neutron-rich heavy fragments to the target neutron content suggests fission as a source of neutron-rich heavy nuclei for present and future rare ion beam facilities, allowing studies of nuclear properties towards the neutron drip-line and investigations of the conditions for nucleosynthesis of heavy nuclei. The breakdowns of the isoscaling behavior around N=62 and N=80 manifest the effect of two shell closures on the dynamics of scission. The shell closure around N=64 can be explained by the deformed shell. The investigation of isoscaling in the spontaneous fission of 248,244Cm further supports such conclusion. The Z-dependence of the isoscaling parameter exhibits a structure which can be possibly related to details of scission dynamics. The fission isoscaling studies can be a suitable tool for the investigation of possible new pathways to synthesize still heavier nuclei.Comment: 7 pages, 3 figures, RevTex, final version, to appear in Phys. Rev. C as a regular articl

Is there Health Insurance in Greece outside EOPYY? Feasibility analysis of creating an independent, private Health Fund for Employees of the Banking Sector

Το χρηματοδοτικό αδιέξοδο και οι λειτουργικές αδυναμίες του νέου ΕΟΠΥΥ το 2011 οδήγησαν την κεντρική διοίκηση στην -ορθή- πρόβλεψη της μη υποχρεωτικότητας της ένταξης στο νέο φορέα των κλάδων που αποδεδειγμένα έχουν προοπτικές βιωσιμότητας. Υπό τη συνθήκη αυτή, η παρούσα μελέτη εξετάζει το κατά πόσο είναι σκόπιμη και εφικτή η δημιουργία ενός αυτόνομουενιαίου ταμείου υγείας τραπεζικών, το οποίο θα λειτουργεί ως νομικό πρόσωπο ιδιωτικού δικαίου και δεν θα επιβαρύνει με τυχόν ελλείμματα τον κρατικό προϋπολογισμό. Η εν λόγω προσέγγιση αποσκοπεί στο να διαμορφώσει ένα υπόδειγμα για περαιτέρω αντίστοιχες αναλύσεις εν όψει της ολοκλήρωσης του νέου χάρτη της ασφάλισης υγείας στη χώρα.Τhe funding impasse and the operational malfunction of the new organization (EOPOYY) in 2011 necessitated the provision for an exemption from this rule, applicable to health insurance funds which could prove their sustainability outside EOPYY. The objective of this paper is to assess the feasibility and viability of the creation of an independent health insurance fund foremployees of the banking sector, which would operate as a private entity and would not burden the state budget with its deficits. The paper aims to develop a paradigm for further analyses as we move towards the establishment of a new, national, health insurance structure

Is there Health Insurance in Greece outside EOPYY? Feasibility analysis of creating an independent, private Health Fund for Employees of the Banking Sector

Το χρηματοδοτικό αδιέξοδο και οι λειτουργικές αδυναμίες του νέου ΕΟΠΥΥ το 2011 οδήγησαν την κεντρική διοίκηση στην -ορθή- πρόβλεψη της μη υποχρεωτικότητας της ένταξης στο νέο φορέα των κλάδων που αποδεδειγμένα έχουν προοπτικές βιωσιμότητας. Υπό τη συνθήκη αυτή, η παρούσα μελέτη εξετάζει το κατά πόσο είναι σκόπιμη και εφικτή η δημιουργία ενός αυτόνομουενιαίου ταμείου υγείας τραπεζικών, το οποίο θα λειτουργεί ως νομικό πρόσωπο ιδιωτικού δικαίου και δεν θα επιβαρύνει με τυχόν ελλείμματα τον κρατικό προϋπολογισμό. Η εν λόγω προσέγγιση αποσκοπεί στο να διαμορφώσει ένα υπόδειγμα για περαιτέρω αντίστοιχες αναλύσεις εν όψει της ολοκλήρωσης του νέου χάρτη της ασφάλισης υγείας στη χώρα.Τhe funding impasse and the operational malfunction of the new organization (EOPOYY) in 2011 necessitated the provision for an exemption from this rule, applicable to health insurance funds which could prove their sustainability outside EOPYY. The objective of this paper is to assess the feasibility and viability of the creation of an independent health insurance fund foremployees of the banking sector, which would operate as a private entity and would not burden the state budget with its deficits. The paper aims to develop a paradigm for further analyses as we move towards the establishment of a new, national, health insurance structure