Search results for "Nuclei"

Pion photo- and electroproduction on nucleons in relativistic chiral perturbation theory

2022

En esta tesis, hemos estudiado la producción de piones mediante pruebas electromagnéticas en nucleones. Para cada uno de los estudios realizados aquí, nos enfocamos en la Teoría Quiral de Perturbaciones (ChPT) relativista para hadrones ligeros: nucleones, piones y los grados de libertad explícitos Delta. Para preservar la covariancia de la teoría, se implementó el método de renormalización en el esquema Extended On Mass Shell (EOMS). En este caso, las divergencias y los términos que violan el conteo de potencias se absorben en las constantes de baja energía (LECs) del Lagrangiano efectivo. El presente trabajo se desarrolló dentro de tres estudios principales relacionados con la producción d…

Characteristics of segmented super clover detector in close geometry decay measurements

2001

Characteristics of the segmented Super Clover germanium detector response in close geometries have been studied. Results obtained with localising hit pattern recognition are compared with results from add-back and individual crystal analysis. The detector has been used at the focal plane of a gas filled recoil separator to detect isomeric gamma-rays from the nuclei produced in the 150Sm(42Ca,4n)188Pb reaction. Coincidence data from the detector was analysed and the level scheme below the 1.2 μ s isomeric state in 188Pb could be deduced. peerReviewed

Identification of the Jπ = 1− state in 218Ra populated via α decay of 222Th

2016

The α decay of 222Th populating the low-lying J π = 3− state, and also a proposed 1− state, in 218Ra has been observed. The observations suggest an excitation energy of 853 keV for the 1− state, which is 60 keV above the 3− state. The hindrance factors of these α decays give a possible boundary to the region of ground-state octupole deformation in the light-actinide nuclei. The relative positions of the J π = 1− and 3− states suggest they are produced by an octupole-vibrational mechanism, as opposed to α clustering or rotations of a reflection-asymmetric octupole-deformed shape. peerReviewed

97/37 Rb 60 : The Cornerstone of the Region of Deformation around A∼100

2015

Excited states of the neutron-rich nuclei 97,99Rb were populated for the first time using the multistep Coulomb excitation of radioactive beams. Comparisons of the results with particle-rotor model calculations provide clear identification for the ground-state rotational band of 97Rb as being built on the πg9/2 [431] 3/2+ Nilsson-model configuration. The ground-state excitation spectra of the Rb isotopes show a marked distinction between single-particle-like structures below N=60 and rotational bands above. The present study defines the limits of the deformed region around A∼100 and indicates that the deformation of 97Rb is essentially the same as that observed well inside the deformed regi…

97/37 Rb 60 : The Cornerstone of the Region of Deformation around A∼100

2015

Testing refined shell-model interactions in the sd shell: Coulomb excitation of 26Na

2015

Background: Shell-model calculations crucially depend on the residual interaction used to approximate the nucleon-nucleon interaction. Recent improvements to the empirical universal sd interaction (USD) describing nuclei within the sd shell yielded two new interactions—USDA and USDB—causing changes in the theoretical description of these nuclei. Purpose: Transitionmatrix elements between excited states provide an excellent probe to examine the underlying shell structure. These observables provide a stringent test for the newly derived interactions. The nucleus 26Na with 7 valence neutrons and 3 valence protons outside the doubly-magic 16O core is used as a test case. Method: A radioactive b…

Inulin Derivatives Obtained Via Enhanced Microwave Synthesis for Nucleic Acid Based Drug Delivery

2015

A new class of therapeutic agents with a high potential for the treatment of different socially relevant human diseases is represented by Nucleic Acid Based Drugs (NABD), including small interfering RNAs (siRNA), decoy oligodeoxynucleotides (decoy ODN) and antisense oligonucleotides (ASOs). Although NABD can be engineered to be specifically directed against virtually any target, their susceptibility to nuclease degradation and the difficulty of delivery into target tissues severely limit their use in clinical practice and require the development of an appropriate nanostructured delivery system. For delivery of NABD, Inulin (Inu), a natural, water soluble and biocompatible polysaccharide, wa…

Occupation probabilities of single particle levels using the microscopic interacting boson model: Application to some nuclei of interest in neutrinol…

2016

We have developed a new method to calculate the occupancies of single particle levels in atomic nuclei. This method has been developed in the context of the microscopic interacting boson model, in which neutron and proton degrees of freedom are treated explicitly. The energies of the single particle levels constitute a very important input for the calculation of the occupancies in this method. In principle these energies can be considered as input parameters that can be fitted to reproduce the experimental occupancies. Instead of fitting, in this study we have extracted the single particle energies from experimental data on nuclei with a particle more or one particle less than a shell closu…

Charge radius changes of even-even neutron-rich Tellurium isotopes

2005

Laser spectroscopy based on resonant ionization of laser-desorbed atoms has been used to study the neutron-rich tellurium isotopes with the COMPLIS facility at ISOLDE-CERN. The isotope shift and the hyperfine structure of several neutron-rich Te isotopes: $^{120–136}$Te and $^{123m–133m}$Te have been measured. From the hyperfine structure and the isotope shift we can extract the magnetic and quadrupole moments and the change in the mean square charge radius respectively. The mean square charge radii of the even-even isotopes have been deduced and their comparison with the known data for the other elements near Z=50 is presented. The experimental $\delta$ is compared with that obtained from …

A Theoretical and Experimental Investigation of the Spectroscopic Properties of a DNA-Intercalator Salphen-Type ZnIIComplex

2014

The photophysical and DNA-binding properties of the cationic zinc(II) complex of 5-triethylammonium methyl salicylidene ortho-phenylenediiminato (ZnL 2 + ) were investi- gated by a combination of experimental and theoretical methods. DFT calculations were performed on both the ground and the first excited states of ZnL 2 + and on its possi- ble mono- and dioxidation products, both in vacuo and in selected solvents mimicked by the polarizable continuum model. Comparison of the calculated absorption and fluores- cence transitions with the corresponding experimental data led to the conclusion that visible light induces a two-elec- tron photooxidation process located on the phenylenediimi- nato…