skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Systematics of the shears mechanism in silver isotopes

Abstract

A systematic investigation of the shears mechanism in silver isotopes has been carried out. Lifetimes have been measured by means of the Doppler-shift attenuation method for states in two magnetic dipole (M1) bands in {sup 105}Ag and one each in {sup 103}Ag and {sup 106}Ag. Experimental total angular momenta and reduced transition strengths for these bands have been compared with the predictions of the tilted axis cranking (TAC) model with configurations involving one g{sub 9/2} proton and quasineutrons from the h{sub 11/2} and g{sub 7/2} or d{sub 5/2} orbitals. There is good overall agreement for both the total angular momenta and reduced transition strengths. The deduced B(M1) strengths, which are a sensitive probe of magnetic rotation, show a decrease consistent with TAC predictions for one M1 band in {sup 105}Ag and in {sup 106}Ag, confirming the shears mechanism as the means of excitation. Furthermore, the staggering in the transition energies in {sup 103}Ag and absence of regular sequences of M1 transitions for N{<=}56 suggest that N=56 is the lower boundary for the appearance of the shears mechanism in this mass region.

Authors:
; ; ; ; ; ; ; ; ; ;  [1];  [2];  [2];  [2];  [2];  [2]
  1. Department of Physics, University of Mumbai, Vidyanagari, Mumbai 400 098 (India)
  2. (India)
Publication Date:
OSTI Identifier:
20771336
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevC.73.034313; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANGULAR MOMENTUM; CRANKING MODEL; DSA METHOD; EXCITATION; LIFETIME; M1-TRANSITIONS; MAGNETIC DIPOLES; PROTONS; ROTATION; SILVER 103; SILVER 105; SILVER 106

Citation Formats

Deo, A.Y., Patel, S.B., Tandel, S.K., Muralithar, S., Singh, R.P., Kumar, R., Bhowmik, R.K., Ghugre, S.S., Singh, A.K., Kumar, V., Amita, Nuclear Science Centre, P.O. Box 10502, New Delhi 110 067, Inter-University Consortium for DAE Facilities, Calcutta 700 091, Department of Physics and Meteorology, IIT Kharagpur, Kharagpur 721 302, Department of Physics, Panjab University, Chandigarh 160 014, and Department of Physics, RBS College, Agra 282 002. Systematics of the shears mechanism in silver isotopes. United States: N. p., 2006. Web. doi:10.1103/PhysRevC.73.034313.
Deo, A.Y., Patel, S.B., Tandel, S.K., Muralithar, S., Singh, R.P., Kumar, R., Bhowmik, R.K., Ghugre, S.S., Singh, A.K., Kumar, V., Amita, Nuclear Science Centre, P.O. Box 10502, New Delhi 110 067, Inter-University Consortium for DAE Facilities, Calcutta 700 091, Department of Physics and Meteorology, IIT Kharagpur, Kharagpur 721 302, Department of Physics, Panjab University, Chandigarh 160 014, & Department of Physics, RBS College, Agra 282 002. Systematics of the shears mechanism in silver isotopes. United States. doi:10.1103/PhysRevC.73.034313.
Deo, A.Y., Patel, S.B., Tandel, S.K., Muralithar, S., Singh, R.P., Kumar, R., Bhowmik, R.K., Ghugre, S.S., Singh, A.K., Kumar, V., Amita, Nuclear Science Centre, P.O. Box 10502, New Delhi 110 067, Inter-University Consortium for DAE Facilities, Calcutta 700 091, Department of Physics and Meteorology, IIT Kharagpur, Kharagpur 721 302, Department of Physics, Panjab University, Chandigarh 160 014, and Department of Physics, RBS College, Agra 282 002. Wed . "Systematics of the shears mechanism in silver isotopes". United States. doi:10.1103/PhysRevC.73.034313.
@article{osti_20771336,
title = {Systematics of the shears mechanism in silver isotopes},
author = {Deo, A.Y. and Patel, S.B. and Tandel, S.K. and Muralithar, S. and Singh, R.P. and Kumar, R. and Bhowmik, R.K. and Ghugre, S.S. and Singh, A.K. and Kumar, V. and Amita and Nuclear Science Centre, P.O. Box 10502, New Delhi 110 067 and Inter-University Consortium for DAE Facilities, Calcutta 700 091 and Department of Physics and Meteorology, IIT Kharagpur, Kharagpur 721 302 and Department of Physics, Panjab University, Chandigarh 160 014 and Department of Physics, RBS College, Agra 282 002},
abstractNote = {A systematic investigation of the shears mechanism in silver isotopes has been carried out. Lifetimes have been measured by means of the Doppler-shift attenuation method for states in two magnetic dipole (M1) bands in {sup 105}Ag and one each in {sup 103}Ag and {sup 106}Ag. Experimental total angular momenta and reduced transition strengths for these bands have been compared with the predictions of the tilted axis cranking (TAC) model with configurations involving one g{sub 9/2} proton and quasineutrons from the h{sub 11/2} and g{sub 7/2} or d{sub 5/2} orbitals. There is good overall agreement for both the total angular momenta and reduced transition strengths. The deduced B(M1) strengths, which are a sensitive probe of magnetic rotation, show a decrease consistent with TAC predictions for one M1 band in {sup 105}Ag and in {sup 106}Ag, confirming the shears mechanism as the means of excitation. Furthermore, the staggering in the transition energies in {sup 103}Ag and absence of regular sequences of M1 transitions for N{<=}56 suggest that N=56 is the lower boundary for the appearance of the shears mechanism in this mass region.},
doi = {10.1103/PhysRevC.73.034313},
journal = {Physical Review. C, Nuclear Physics},
number = 3,
volume = 73,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • High-spin states of {sup 106}Ag were populated via the fusion-evaporation reaction {sup 100}Mo ({sup 11}B,5n){sup 106}Ag at a beam energy of 60 MeV. A rich level scheme with six band structures has been established. A high-K negative-parity band has been identified and assigned to the pig{sub 9/2} x nu[h{sub 11/2}(g{sub 7/2}/d{sub 5/2}){sup 2}] configuration. The positive parity DELTAI=1 band, built on the 12{sup +} state, is discussed in terms of the magnetic rotation model. The systematic study of similar bands in the Aapprox110 mass region indicates that the magnetic rotation phenomenon has, as lower boundary, the Ag isotopes at Z=47.
  • No abstract prepared.
  • Experimental total beta-decay energies of neutron-rich silver and cadmium isotopes are presented. The sources have been produced as mass-separated fission products by means of the on-line--isotope-separator technique. Beta spectra have been recorded in coincidence with different gamma transitions, and Q/sub ..beta../ values for /sup 116en-dash121/Ag, /sup 119/Cd, and /sup 121/Cd have been deduced. The atomic mass excess is derived for these nuclei, and comparisons are made with mass formula predictions.
  • High-spin states of {sup 197-202}Pb were populated by using several different reactions at the VICKSI accelerator of the HMI Berlin. Gamma-ray coincidences, were measured with the OSIRIS spectrometer consisting of 12 Compton-suppressed Ge detectors and a multiplicity filter of 48 BGO detectors. Sixteen regular sequences of enhanced magnetic dipole transitions, with weak E2 crossovers in some cases, have been found. Six of them have been connected to the previously known spherical level scheme at lower spin. They are built on oblate proton 2p-2h states that are coupled to neutron-hole excitations. Tilted-axis cranking calculations show that the angular momentum along withmore » the bands is predominantly generated by the shears effect, a continuous and simultaneous reorientation of the proton and neutron spins into the direction of the total angular momentum.« less
  • Tilt angles, deformation parameters, angular momenta, and reduced magnetic dipole and electric quadrupole transition probabilities are calculated within the framework of the tilted-axis cranking model for shears bands in the neutron-deficient Pb isotopes {sup 193}Pb to {sup 202}Pb. The self-consistently calculated quadrupole-deformation parameters for the various configurations lie around {epsilon}{sub 2}=-0.1, and the triaxiality is small. The tilt angle, i.e., the angle between the angular momentum and the nuclear symmetry axis, remains almost constant within each band, showing only a small increase toward higher angular momenta. The angular momentum increases mainly due to the shears effect, which is a step-by-stepmore » alignment of high-j proton and neutron orbitals into the direction of the total angular momentum. Calculated and experimental M1 transition rates are in good agreement. They decrease with increasing spin within the bands as expected for the shears effect. The calculated B(E2) values show only a weak spin dependence. However, the experimental B(E2) values have large errors, and more accurate data are needed to decide between the present model and a recently suggested geometrical approach.« less