Simulation Study on Computer Tomography Imaging of Nuclear Distribution by Quasi Monoenergetic Gamma Rays with Nuclear Resonance Fluorescence: case study for ELI-NP application

CoE on Sustainable Energy System (Thai-Japan), Faculty of Engineering, Rajamangala University of Technology Thanyaburi (RMUTT), ThailandNon-destructive inspection carried out by using nuclear resonances excited by an MeV energy region gamma ray is a promising method. The high penetrability of MeV gamma ray of nuclear resonant energy makes possible the detection of nuclides surrounded by massive materials. As an application of this method, computed tomography imaging of nuclear distribution inside objects can be reconstructed from transmission factor of gamma rays. We have studied the image reconstruction of the nuclear distribution using Monte-Carlo simulations to estimate the gamma-ray transmission factor assuming the ELI-NP facility where about 3 order higher intensity of quasi-monoenergetic gamma rays will be available

Transverse Dynamics and Energy Tuning of Fast Electrons Generated in Sub-Relativistic Intensity Laser Pulse Interaction with Plasmas

The regimes of quasi-mono-energetic electron beam generation were experimentally studied in the sub-relativistic intensity laser plasma interaction. The observed electron acceleration regime is unfolded with two-dimensional-particle-in-cell simulations of laser-wakefield generation in the self-modulation regime.Comment: 10 pages, 5 figure

Structure of isobaric analog states in 91Nb populated by the 90Zr(a,t) reaction

Decay via proton emission of isobaric analog states (IAS's) in $^{91}{Nb}$ was studied using the $^{90}{Zr}(\alpha,t)$ reaction at $E_\alpha$=180 MeV. This study provides information about the damping mechanism of these states. Decay to the ground state and low-lying phonon states in $^{90}{Zr}$ was observed. The experimental data are compared with theoretical predictions wherein the IAS `single-particle' proton escape widths are calculated in a continuum RPA approach. The branching ratios for decay to the phonon states are explained using a simple model.Comment: 3 figures. submitted to Phys. Lett.

Structure of Excited States of 10Be studied with Antisymmetrized Molecular Dynamics

We study structure of excited states of 10Be with the method of variation after spin parity projection in the framework of antisymmetrized molecular dynamics. Present calculations describe many excited states and reproduce the experimental data of E2 and E1 transitions and the new data of the $\beta$ transition strength successfully. We make systematic discussions on the molecule-like structures of light unstable nuclei and the important role of the valence neutrons based on the results obtained with the framework which is free from such model assumptions as the existence of inert cores and clusters.Comment: 15 pages, RevTex, seven postscript figures (using epsf.sty

Measurement of the Gamow-Teller Strength Distribution in 58Co via the 58Ni(t,3He) reaction at 115 MeV/nucleon

Electron capture and beta decay play important roles in the evolution of pre-supernovae stars and their eventual core collapse. These rates are normally predicted through shell-model calculations. Experimentally determined strength distributions from charge-exchange reactions are needed to test modern shell-model calculations. We report on the measurement of the Gamow-Teller strength distribution in 58Co from the 58Ni(t,3He) reaction with a secondary triton beam of an intensity of ~10^6 pps at 115 MeV/nucleon and a resolution of \~250 keV. Previous measurements with the 58Ni(n,p) and the 58Ni(d,2He) reactions were inconsistent with each other. Our results support the latter. We also compare the results to predictions of large-scale shell model calculations using the KB3G and GXPF1 interactions and investigate the impact of differences between the various experiments and theories in terms of the weak rates in the stellar environment. Finally, the systematic uncertainties in the normalization of the strength distribution extracted from 58Ni(3He,t) are described and turn out to be non-negligible due to large interferences between the dL=0, dS=1 Gamow-Teller amplitude and the dL=2, dS=1 amplitude.Comment: 14 pages, 8 figure

Structure of excited states of Be-11 studied with Antisymmetrized Molecular Dynamics

The structures of the ground and excited states of Be-11 were studied with a microscopic method of antisymmetrized molecular dynamics. The theoretical results reproduce the abnormal parity of the ground state and predict various kinds of excited states. We suggest a new negative-parity band with a well-developed clustering structure which reaches high-spin states. Focusing on a $2\alpha$ clustering structure, we investigated structure of the ground and excited states. We point out that molecular orbits play important roles for the intruder ground state and the low-lying $2\hbar \omega$ states. The features of the breaking of $\alpha$ clusters were also studied with the help of data for Gamow-Teller transitions.Comment: 24 pages, 7 figures, to be submitted to Phys.Rev.

Quantum Monte Carlo calculations of A=9,10A=9,10 nuclei

We report on quantum Monte Carlo calculations of the ground and low-lying excited states of $A=9,10$ nuclei using realistic Hamiltonians containing the Argonne $v_{18}$ two-nucleon potential alone or with one of several three-nucleon potentials, including Urbana IX and three of the new Illinois models. The calculations begin with correlated many-body wave functions that have an $\alpha$-like core and multiple p-shell nucleons, $LS$-coupled to the appropriate $(J^{\pi};T)$ quantum numbers for the state of interest. After optimization, these variational trial functions are used as input to a Green's function Monte Carlo calculation of the energy, using a constrained path algorithm. We find that the Hamiltonians that include Illinois three-nucleon potentials reproduce ten states in $^9$Li, $^9$Be, $^{10}$Be, and $^{10}$B with an rms deviation as little as 900 keV. In particular, we obtain the correct 3$^+$ ground state for $^{10}$B, whereas the Argonne $v_{18}$ alone or with Urbana IX predicts a 1$^+$ ground state. In addition, we calculate isovector and isotensor energy differences, electromagnetic moments, and one- and two-body density distributions.Comment: 28 pages, 12 tables, 7 figure

Stability improvement of a laser-accelerated electron beam and the pulse width measurement of the electron beam

Laser wakefield acceleration has the possibility to generate an ultrashort electron beam of the order of femtoseconds or less. In applications of these laser accelerated electron beams, stable and controllable electron beams are necessary. A high stability electron bunch is generated by laser wakefield acceleration with the help of a colliding laser pulse (optical injection). Stable and monoenergetic electron beams have been generated in the self-injection scheme of laser acceleration by using a Nitrogen gas jet target. The electron interaction with the laser field results in transverse oscillations of the electron beam. From the electron oscillation period dependence on the electron energy we find that the electron beam width is equal to 1.7 fs (rms).В процессе ускорения кильватерными волнами возможна генерация сверхкоротких электронных пучков фемтосекундной длительностью. Для приложений требуются электронные пучки с воспроизводимыми и котролируемыми параметрами. Оптическая инжекция, использующая сталкивающиеся лазерные импульсы, обеспечивает высокую воспроизводимость параметров пучков ускоренных электронов. Моноэнергетические пучки электронов с воспроизводимыми параметрами были получены при «самоинжекции» в кильватерную волну в экспериментах, использующих в качестве мишени струю азота. Взаимодействие электронов с излучением лазерного импульса приводит к поперечным осцилляциям электронного пучка. Анализ наблюдаемой в эксперименте зависимости периода осцилляций от энергии электронов позволяет найти длительность электронного пучка, равную 1.7 фс.В процесі прискорення кільватерними хвилями можлива генерація надкоротких електронних пучків фемтосекундної тривалості. Для додатків потрібні електронні пучки з відтворюючими і котролюючими параметрами. Оптична інжекція, що використовує зіштовхуючі лазерні імпульси, забезпечує високу відтворюваність параметрів пучків прискорених електронів. Моноенергетичні пучки електронів з відтворюваними параметрами були отримані при «самоінжекції» в кільватерну хвилю в експериментах, в яких в якості мішені використовувалася струмінь азоту. Взаємодія електронів з випромінюванням лазерного імпульсу призводить до поперечних осциляцій електронного пучка. Аналіз спостерігаючої в експерименті залежності періоду осциляцій від енергії електронів дозволяє знайти тривалість електронного пучка, яка дорівнює 1.7 фс

Low-lying states of 56 Fe

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Do Hadronic Charge Exchange Reactions Measure Electroweak L = 1 Strength?

An eikonal model has been used to assess the relationship between calculated strengths for first forbidden beta decay and calculated cross sections for (p,n) charge exchange reactions. It is found that these are proportional for strong transitions, suggesting that hadronic charge exchange reactions may be useful in determining the spin-dipole matrix elements for astrophysically interesting leptonic transitions.Comment: 14 pages, 5 figures, Submitted to Physical Review