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Gamma-ray bursts (GRBs) are possible sources of ultra-high-energy cosmic rays (UHE-CRs). To test the GRB origin of UHECRs, it is essential to search for characteristic, proton-induced signatures of secondary radiation. In this paper we present our recent results of Monte Carlo simulations that model the broadband prompt emission of GRBs including various processes associated with electrons and protons accelerated to high energies. The most notable effect of accelerated protons on the high-energy spectra is the synchrotron emission from secondary electron-positron pairs injected by photomeson interactions. Secondary photons tend to make the spectra flat, so a spectral flattening in the GeV-TeV bands may serve as a signature of UHECR acceleration. In some cases, the proton-induced photons overwhelm the photon field, resulting in a spectral peak due to inverse Compton emission from secondary pairs located around 107 eV. We can expect to detect synchrotron photons from protons or muons. Observations with GLAST or with atmospheric Cerenkov telescopes can provide useful estimates of the bulk Lorents factor and can constrain the proton acceleration efficiency. [ABSTRACT FROM AUTHOR]

Some of the most fascinating questions about the limits of nuclear stability are confronted in the heaviest nuclei. How many more new elements can be synthesized? What are the nuclear and chemical properties of these exotic nuclei? Does the “Island of Stability” exist and can we ever explore the isotopes inhabiting that nuclear region? This paper will focus on the current experimental research on the synthesis and characterization of superheavy nuclei with Z>112 from the Dubna/Livermore collaboration. Reactions using 48Ca projectiles from the U400 cyclotron and actinide targets (233,238U, 237Np, 242,244Pu, 243Am, 245,248Cm, 249Cf) have been investigated using the Dubna Gas Filled Recoil Separator in Dubna over the last 8 years. In addition, several experiments have been performed to investigate the chemical properties of some of the observed longer-lived isotopes produced in these reactions. Some comments will be made on nuclear reactions used for the production of the heaviest elements. A summary of the current status of the upper end of the chart of nuclides will be presented. [ABSTRACT FROM AUTHOR]

In this paper we show how effective parameters such as effective binding energies can be defined for a proton in the combined nuclear-Coulomb potential, including also the target potential, in the case in which the proton is bound in a nucleus which is partner of a nuclear reaction. Using such effective parameters the proton behaves similarly to a neutron. In this way some unexpected results obtained from dynamical calculations for reactions initiated by very weakly bound proton halo nuclei can be interpreted. Namely the fact that stripping dominates the nuclear breakup cross section which in turn dominates over the Coulomb breakup even when the target is heavy at medium to high incident energies. Our interpretation helps also clarifying why the existence and characteristics of a proton halo extracted from different types of data have sometimes appeared contradictory. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

The mass distributions of fragments produced by proton-induced fission of 232Th, 235U, 238U, and 237Np at proton energies of 50 and 96 MeV have been measured. The measurements were carried out at The Svedberg Laboratory, Uppsala, Sweden using a high-precision time-of-flight spectrometer for fission fragments and fission neutrons. The measured mass distributions are compared to ones calculated using the TALYS code. Using proton-induced reactions to simulate the outcome of more difficult measurements with neutron beams is discussed. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

The photoproduction of the Λ*(1520) on both the proton and neutron have been studied by using the CLAS eg3 run data set. The reactions are γd→K+Λ*(n) and γd→K0Λ*(p) with Λ*→pK-. Preliminary total and differential cross sections have been extracted in the photon energy region 1.75 GeVγ<5.50 GeV. This is the first time that the photoproduction of Λ*(1520) on the neutron is reported, and we will extend the results on the proton to higher energies than in previous studies. [ABSTRACT FROM AUTHOR]

The spectroscopy of fission fragments, obtained by the 18O+208Pb fusion-fission reaction at 85 MeV bombarding energy, has been performed with the Euroball IV γ-array. High-spin states in many neutron-rich Se, Br, Kr and Rb of the 78Ni region nuclei have been identified for the first time. Several physical aspects which govern the nuclear structure in this mass region are underlined thanks to the new results. Among those, empirical values of the residual proton-neutron interactions have been extracted for the πf5/2xvd5/2 and πp3/2xvd5/2 configurations. [ABSTRACT FROM AUTHOR]

At a certain finite neck radius during the descent of a fissioning nucleus from the saddle to the scission point, the attractive nuclear forces can no more withstand the repulsive Coulomb forces producing the neck rupture and the sudden absorption of the neck stubs by the fragments. At that moment the nucleons, although still characterized by their pre-scission wave functions, find themselves in the newly created potential of their interaction with the separated fragments. Their wave functions become wave packets with components in the continuum. The probability to populate such states gives evidently the emission probability of nucleons at scission. In this way we have studied scission neutrons and protons for the fissioning nucleus 236U, using two-dimensional realistic nuclear shapes. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]

Excitation functions of the reactions natIr(p,xn)188,189,191Pt and natIr(p,x)186,187,188,189,190,192Ir were measured up to 70 MeV for practical applications. The measured experimental data were compared with the earlier results and analyzed using theoretical calculations based on the model code Alice-IPPE, The new experimental data show significant deviations from the earlier experimental results. Good agreement was found on average with the model calculation. Applications are also discussed. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]