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Title: In-beam gamma ray and conversion electron study of {sup 250}Fm

Abstract

We report on a set of in-beam studies of excited states in {sup 250}Fm. We detected prompt {gamma} rays by using the JUROSPHERE IV array and conversion electrons by using the SACRED spectrometer. Both devices were used in conjunction with the RITU gas-filled recoil separator located at the University of Jyvaeskylae. {sup 250}Fm nuclei were produced through the {sup 204}Hg({sup 48}Ca,2n){sup 250}Fm fusion-evaporation reaction. An experimental excitation function gave a maximum reaction cross section of (980 {+-} 160) nb at an energy of 209 MeV in the center of the target. Tagging techniques were employed, and a number of E2 transitions were observed that connected the ground-state band levels from spin 4{sup +} up to 18{sup +}. The highly converted 4{sup +}{yields}2{sup +} transition is observed only by use of conversion electron spectroscopy. The observed ground-state band transitions indicate a rotational structure. We deduce a quadrupole deformation parameter of {beta}{sub 2}=0.28 {+-} 0.02. A low-energy background of apparent nuclear origin is observed in conversion electrons and postulated to arise from the decay of high-K bands. The half-life of {sup 250}Fm is measured to be 30.4 {+-} 1.5 0009m.

Authors:
; ; ; ; ; ; ; ; ; ; ;  [1]; ; ; ; ; ; ; ;  [2]
  1. Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 7ZE (United Kingdom)
  2. Department of Physics, P.O. Box 35 (YFL), FIN-40014, University of Jyvaeskylae (Finland) (and others)
Publication Date:
OSTI Identifier:
20771259
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 73; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevC.73.024308; (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; CALCIUM 48 REACTIONS; E2-TRANSITIONS; ELECTRON SPECTRA; ELECTRON SPECTROSCOPY; ELECTRONS; EVAPORATION MODEL; EXCITATION FUNCTIONS; FERMIUM 250; GAMMA RADIATION; GAMMA SPECTRA; GROUND STATES; HALF-LIFE; INTERNAL CONVERSION; MERCURY 204 TARGET; MEV RANGE; NUCLEAR DEFORMATION; QUADRUPOLES; ROTATIONAL STATES; SPIN

Citation Formats

Bastin, J.E., Herzberg, R.-D., Butler, P.A., Jones, G.D., Page, R.D., Jenkins, D.G., Amzal, N., Brew, P.M.T., Hammond, N.J., Humphreys, R.D., Ikin, P.J.C., Page, T., Greenlees, P.T., Jones, P.M., Julin, R., Juutinen, S., Kankaanpaeae, H., Keenan, A., Kettunen, H., and Kuusiniemi, P. In-beam gamma ray and conversion electron study of {sup 250}Fm. United States: N. p., 2006. Web. doi:10.1103/PhysRevC.73.024308.
Bastin, J.E., Herzberg, R.-D., Butler, P.A., Jones, G.D., Page, R.D., Jenkins, D.G., Amzal, N., Brew, P.M.T., Hammond, N.J., Humphreys, R.D., Ikin, P.J.C., Page, T., Greenlees, P.T., Jones, P.M., Julin, R., Juutinen, S., Kankaanpaeae, H., Keenan, A., Kettunen, H., & Kuusiniemi, P. In-beam gamma ray and conversion electron study of {sup 250}Fm. United States. doi:10.1103/PhysRevC.73.024308.
Bastin, J.E., Herzberg, R.-D., Butler, P.A., Jones, G.D., Page, R.D., Jenkins, D.G., Amzal, N., Brew, P.M.T., Hammond, N.J., Humphreys, R.D., Ikin, P.J.C., Page, T., Greenlees, P.T., Jones, P.M., Julin, R., Juutinen, S., Kankaanpaeae, H., Keenan, A., Kettunen, H., and Kuusiniemi, P. Wed . "In-beam gamma ray and conversion electron study of {sup 250}Fm". United States. doi:10.1103/PhysRevC.73.024308.
@article{osti_20771259,
title = {In-beam gamma ray and conversion electron study of {sup 250}Fm},
author = {Bastin, J.E. and Herzberg, R.-D. and Butler, P.A. and Jones, G.D. and Page, R.D. and Jenkins, D.G. and Amzal, N. and Brew, P.M.T. and Hammond, N.J. and Humphreys, R.D. and Ikin, P.J.C. and Page, T. and Greenlees, P.T. and Jones, P.M. and Julin, R. and Juutinen, S. and Kankaanpaeae, H. and Keenan, A. and Kettunen, H. and Kuusiniemi, P.},
abstractNote = {We report on a set of in-beam studies of excited states in {sup 250}Fm. We detected prompt {gamma} rays by using the JUROSPHERE IV array and conversion electrons by using the SACRED spectrometer. Both devices were used in conjunction with the RITU gas-filled recoil separator located at the University of Jyvaeskylae. {sup 250}Fm nuclei were produced through the {sup 204}Hg({sup 48}Ca,2n){sup 250}Fm fusion-evaporation reaction. An experimental excitation function gave a maximum reaction cross section of (980 {+-} 160) nb at an energy of 209 MeV in the center of the target. Tagging techniques were employed, and a number of E2 transitions were observed that connected the ground-state band levels from spin 4{sup +} up to 18{sup +}. The highly converted 4{sup +}{yields}2{sup +} transition is observed only by use of conversion electron spectroscopy. The observed ground-state band transitions indicate a rotational structure. We deduce a quadrupole deformation parameter of {beta}{sub 2}=0.28 {+-} 0.02. A low-energy background of apparent nuclear origin is observed in conversion electrons and postulated to arise from the decay of high-K bands. The half-life of {sup 250}Fm is measured to be 30.4 {+-} 1.5 0009m.},
doi = {10.1103/PhysRevC.73.024308},
journal = {Physical Review. C, Nuclear Physics},
number = 2,
volume = 73,
place = {United States},
year = {Wed Feb 15 00:00:00 EST 2006},
month = {Wed Feb 15 00:00:00 EST 2006}
}