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Title: Lifetime and g-factor measurements of excited states using Coulomb excitation and alpha transfer reactions

Abstract

In this contribution the challenges in the use of a setup to simultaneously measure lifetimes and g-factor values will be presented. The simultaneous use of the transient field technique and the Doppler Shift Attenuation Method, to measure magnetic moments and lifetimes respectively, allows to obtain a complete characterization of the currents of nucleons and the deformation in excited states close to the ground state. The technique is at the moment limited to Coulomb excitation and alpha-transfer reactions, what opens an interesting perspective to consider this type of experiments with radioactive beams. The use of deep-inelastic and fusion-evaporation reactions will be discussed. An example of a setup that makes use of a beam of {sup 106}Cd to study excited states of {sup 110}Sn and the beam nuclei itself will be presented.

Authors:
;  [1]
  1. Physics Department, Universidad Nacional de Colombia, Bogotá D.C. (Colombia)
Publication Date:
OSTI Identifier:
22608495
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1753; Journal Issue: 1; Conference: Latin American symposium on nuclear physics and applications, Medellin (Colombia), 30 Nov - 4 Dec 2015; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ALPHA-TRANSFER REACTIONS; ATTENUATION; BEAMS; CADMIUM 106; COULOMB EXCITATION; DEEP INELASTIC SCATTERING; DEFORMATION; DOPPLER EFFECT; DSA METHOD; EVAPORATION; EXCITED STATES; GROUND STATES; LANDE FACTOR; LIFETIME; MAGNETIC MOMENTS; NUCLEONS; TIN 110; TRANSIENTS

Citation Formats

Guevara, Z. E., E-mail: zjguevaram@unal.edu.co, and Torres, D. A., E-mail: datorresg@unal.edu.co. Lifetime and g-factor measurements of excited states using Coulomb excitation and alpha transfer reactions. United States: N. p., 2016. Web. doi:10.1063/1.4955347.
Guevara, Z. E., E-mail: zjguevaram@unal.edu.co, & Torres, D. A., E-mail: datorresg@unal.edu.co. Lifetime and g-factor measurements of excited states using Coulomb excitation and alpha transfer reactions. United States. doi:10.1063/1.4955347.
Guevara, Z. E., E-mail: zjguevaram@unal.edu.co, and Torres, D. A., E-mail: datorresg@unal.edu.co. Thu . "Lifetime and g-factor measurements of excited states using Coulomb excitation and alpha transfer reactions". United States. doi:10.1063/1.4955347.
@article{osti_22608495,
title = {Lifetime and g-factor measurements of excited states using Coulomb excitation and alpha transfer reactions},
author = {Guevara, Z. E., E-mail: zjguevaram@unal.edu.co and Torres, D. A., E-mail: datorresg@unal.edu.co},
abstractNote = {In this contribution the challenges in the use of a setup to simultaneously measure lifetimes and g-factor values will be presented. The simultaneous use of the transient field technique and the Doppler Shift Attenuation Method, to measure magnetic moments and lifetimes respectively, allows to obtain a complete characterization of the currents of nucleons and the deformation in excited states close to the ground state. The technique is at the moment limited to Coulomb excitation and alpha-transfer reactions, what opens an interesting perspective to consider this type of experiments with radioactive beams. The use of deep-inelastic and fusion-evaporation reactions will be discussed. An example of a setup that makes use of a beam of {sup 106}Cd to study excited states of {sup 110}Sn and the beam nuclei itself will be presented.},
doi = {10.1063/1.4955347},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1753,
place = {United States},
year = {Thu Jul 07 00:00:00 EDT 2016},
month = {Thu Jul 07 00:00:00 EDT 2016}
}
  • The g factor of the 2{sub 1}{sup +} state in {sup 70}Ge was remeasured using a different experimental approach. Furthermore, for the first time an experimental value (although with a large uncertainty) was obtained for the g factor of the 2{sub 2}{sup +} state in {sup 70}Ge. All this was accomplished by employing the technique of {alpha} transfer to an energetic {sup 66}Zn ion beam in inverse kinematics combined with transient magnetic fields in ferromagnetic gadolinium. The value of the g(2{sub 1}{sup +}) factor obtained ranges from +0.32(11) to +0.43(12), subject to certain assumptions. This range of values is inmore » general agreement with the range of values in the literature, where Coulomb excitation and different IMPAC techniques were used. Lifetimes of several low-lying states were redetermined using the Doppler-Shift-Attenuation-Method. The deduced B(E2) values and the g(2{sub 1}{sup +}) factor are discussed within the framework of large-scale full fp shell model calculations with a closed {sup 40}Ca core and including excitations from the f{sub 7/2} orbital. The results are compared with recent data for {sup 68}Ge and {sup 68}Zn.« less
  • Cited by 1
  • The Cd isotopes are well studied, but experimental data for the rare isotopes are sparse. At energies above the Coulomb barrier, higher states become accessible. Remeasure and supplement existing lifetimes and magnetic moments of low-lying states in 106Cd. Methods: In an inverse kinematics reaction, a 106Cd beam impinging on a 12C target was used to Coulomb excite the projectiles. The high recoil velocities provide a unique opportunity to measure g factors with the transient-field technique and to determine lifetimes from lineshapes by using the Doppler-shift-attenuation method. Large-scale shell-model calculations were carried out for 106Cd. As a result, the g factorsmore » of the 2 + 1 and 4 + 1 states in 106Cd were measured to be g(2 + 1) = +0.398(22) and g(4 + 1) = +0.23(5). A lineshape analysis yielded lifetimes in disagreement with published values. The new results are τ( 106Cd; 2 + 1) = 7.0(3) ps and τ( 106Cd; 4 + 1) = 2.5(2) ps. The mean life τ( 106Cd; 2 + 2) = 0.28(2) ps was determined from the fully-Doppler-shifted γ line. Mean lives of τ( 106Cd; 4 + 3) = 1.1(1) ps and τ( 106Cd; 3 1) = 0.16(1) ps were determined for the first time. In conclusion, the newly measured g(4 + 1) of 106Cd is found to be only 59% of the g(2 + 1). This difference cannot be explained by either shell-model or collective-model calculations.« less
  • The Cd isotopes are well studied, but experimental data for the rare isotopes are sparse. At energies above the Coulomb barrier, higher states become accessible. Purpose: Remeasure and supplement existing lifetimes and magnetic moments of low-lying states in Cd106. In an inverse kinematics reaction, a Cd106 beam impinging on a C12 target was used to Coulomb excite the projectiles. The high recoil velocities provide a unique opportunity to measure g factors with the transient-field technique and to determine lifetimes from lineshapes by using the Doppler-shift-attenuation method. Large-scale shell-model calculations were carried out for Cd106. The g factors of the 21+more » and 41+ states in Cd106 were measured to be g(21+)=+0.398(22) and g(41+)=+0.23(5). A lineshape analysis yielded lifetimes in disagreement with published values. The new results are τ(Cd106;21+)=7.0(3)ps and τ(Cd106;41+)=2.5(2)ps. The mean life τ(Cd106;22+)=0.28(2)ps was determined from the fully-Doppler-shifted γ line. Mean lives of τ(Cd106;43+)=1.1(1)ps and τ(Cd106;31-)=0.16(1)ps were determined for the first time. The newly measured g(41+) of Cd106 is found to be only 59% of the g(21+). This difference cannot be explained by either shell-model or collective-model calculations.« less
  • We report on the measurement of lifetimes and magnetic moments of yrast states in /sup 134/Nd and /sup 136/Nd. Lifetimes in the 10--100 ps range were measured via the recoil distance Doppler shift method applied to the reactions /sup 110/Pd(/sup 28,30/Si,4n) at 120--125 MeV beam energy. Magnetic moments of the 21 state in /sup 134/Nd and the 10 and 12 yrast states in /sup 136/Nd were deduced from the integral Larmor precessions measured after recoil implantation in a magnetized nickel foil, via the reactions /sup 76/Ge(/sup 62,64/Ni,4n). The 10 backbending state in /sup 136/Nd results from h/sub 11/2/ proton (twomore » quasiparticle) alignment. The paramagnetic relaxation time of Nd in nickel was measured by Coulomb excitation and implantation of /sup 148/Nd(21 ).« less