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Title: Improved measurement of the {sup 44}Ti half-life from a 14-year long study

Abstract

The half-life of {sup 44}Ti was determined by following the decay of {sup 44}Ti and {sup 60}Co for 14 yr. Mixed sources containing {sup 44}Ti and {sup 60}Co and pure sources of {sup 44}Ti and {sup 60}Co were prepared and their {gamma}-ray spectra were measured with a Ge spectrometer once or twice a year. Counts in the 1157.0-keV {gamma}-ray photopeak of {sup 44}Ti and the 1173.2- and 1332.5-keV {gamma}-ray photopeaks of {sup 60}Co were used for this measurement. From the decay of the {sup 44}Ti and {sup 60}Co activity ratios, the half-life of {sup 44}Ti was determined. Using a value of 5.2711{+-}0.0004 yr for {sup 60}Co half-life, we determined the half-life of {sup 44}Ti as 58.9{+-}0.3 yr. Special efforts were made to check for systematic errors and these were found to be negligible within the quoted uncertainty.

Authors:
; ; ; ; ; ;  [1];  [2];  [3]
  1. Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
  2. (Israel)
  3. (VERA), Institut fuer Isotopenforschung und Kernphysik, Universitaet Wien, Waehringer Strasse 17, A-1090 Vienna (Austria)
Publication Date:
OSTI Identifier:
20864245
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 74; Journal Issue: 6; Other Information: DOI: 10.1103/PhysRevC.74.065803; (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; COBALT 60; ELECTRON CAPTURE; ENERGY LEVELS; ERRORS; GAMMA RADIATION; GAMMA SPECTRA; GAMMA SPECTROSCOPY; HALF-LIFE; KEV RANGE; LIFETIME; NUCLEAR DECAY; TITANIUM 44

Citation Formats

Ahmad, I., Greene, J. P., Moore, E. F., Ghelberg, S., Ofan, A., Paul, M., Kutschera, W., Racah Institute of Physics, Hebrew University, Jerusalem, 91904, and Vienna Environmental Research Accelerator. Improved measurement of the {sup 44}Ti half-life from a 14-year long study. United States: N. p., 2006. Web. doi:10.1103/PHYSREVC.74.065803.
Ahmad, I., Greene, J. P., Moore, E. F., Ghelberg, S., Ofan, A., Paul, M., Kutschera, W., Racah Institute of Physics, Hebrew University, Jerusalem, 91904, & Vienna Environmental Research Accelerator. Improved measurement of the {sup 44}Ti half-life from a 14-year long study. United States. doi:10.1103/PHYSREVC.74.065803.
Ahmad, I., Greene, J. P., Moore, E. F., Ghelberg, S., Ofan, A., Paul, M., Kutschera, W., Racah Institute of Physics, Hebrew University, Jerusalem, 91904, and Vienna Environmental Research Accelerator. Fri . "Improved measurement of the {sup 44}Ti half-life from a 14-year long study". United States. doi:10.1103/PHYSREVC.74.065803.
@article{osti_20864245,
title = {Improved measurement of the {sup 44}Ti half-life from a 14-year long study},
author = {Ahmad, I. and Greene, J. P. and Moore, E. F. and Ghelberg, S. and Ofan, A. and Paul, M. and Kutschera, W. and Racah Institute of Physics, Hebrew University, Jerusalem, 91904 and Vienna Environmental Research Accelerator},
abstractNote = {The half-life of {sup 44}Ti was determined by following the decay of {sup 44}Ti and {sup 60}Co for 14 yr. Mixed sources containing {sup 44}Ti and {sup 60}Co and pure sources of {sup 44}Ti and {sup 60}Co were prepared and their {gamma}-ray spectra were measured with a Ge spectrometer once or twice a year. Counts in the 1157.0-keV {gamma}-ray photopeak of {sup 44}Ti and the 1173.2- and 1332.5-keV {gamma}-ray photopeaks of {sup 60}Co were used for this measurement. From the decay of the {sup 44}Ti and {sup 60}Co activity ratios, the half-life of {sup 44}Ti was determined. Using a value of 5.2711{+-}0.0004 yr for {sup 60}Co half-life, we determined the half-life of {sup 44}Ti as 58.9{+-}0.3 yr. Special efforts were made to check for systematic errors and these were found to be negligible within the quoted uncertainty.},
doi = {10.1103/PHYSREVC.74.065803},
journal = {Physical Review. C, Nuclear Physics},
number = 6,
volume = 74,
place = {United States},
year = {Fri Dec 15 00:00:00 EST 2006},
month = {Fri Dec 15 00:00:00 EST 2006}
}
  • A new method to produce and implant a well determined number of {sup 44}Ti has been developed. {sup 44}Ti samples were used to measure {sup 44}Ti gamma-emission spectra and to determine the half-life of {sup 44}Ti. The preliminary result is T 1/2=58{plus_minus}10 years (1{sigma} confidence level). By improving the experimental technique, the authors expect to reduce the uncertainty below 10%. (AIP) {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.
  • We report on a measurement of the {sup 44}Ti half-life aimed at lowering existing systematic uncertainties in this value, which is important to astrophysics. The half-life was measured by following the decay of {sup 44}Ti relative to {sup 60}Co for about 5yr and the measurements were performed independently in three laboratories{emdash}Argonne, Jerusalem, and Torino. We suggest to combine our result, 59.0{plus_minus}0.6yr, with the one from the accompanying Letter by G{umlt o}rres {ital et al.,} 60.3{plus_minus}1.3yr, to obtain a current {open_quotes}best value{close_quotes} for the half-life of {sup 44}Ti of 59.2{plus_minus}0.6 yr (1{sigma} error). {copyright} {ital 1998} {ital The American Physical Society}
  • Previous measurements of the {sup 44}Ti half-life display large uncertainties, and the reported half-lives range from 43 to 66 yrs. Since remnants of supernovae, especially SN 1987A, are expected to be partially powered by the decay of {sup 44}Ti it is important for predicting the abundance of available {sup 44}Ti to know the half-life to higher precision.
  • Recent measurements of galactic radioactivity with the Compton Gamma Ray Observatory reported {sup 44}Ti activity from the supernova remnant Cassiopeia A. The absolute amount of {sup 44}Ti provides a stringent test for current supernova models. The main uncertainty is presently the half-life of {sup 44}Ti . We report a new measurement of the half-life of {sup 44}Ti applying a novel technique using a mixed radioactive ion beam containing {sup 44}Ti as well as {sup 22}Na ions. This method allows the reliable determination of the half-life of {sup 44}Ti with high accuracy, t{sub 1/2}=(60.3{plus_minus}1.3) yr . The {sup 44}Ti abundance determinedmore » for Cassiopeia A with this half-life agrees with theoretical predictions within the observational uncertainties. {copyright} {ital 1998} {ital The American Physical Society}« less
  • We present the results of two separate measurements of the half-life of {sup 44}Ti relative to those of {sup 22}Na and {sup 207}Bi, respectively. By comparing the numbers of 1157-keV {gamma} rays from {sup 44}Ti to those of 1274-keV {gamma} rays from {sup 22}Na observed from a mixed source over a period of approximately 2 yr, we determined the half-life of {sup 44}Ti to be 61.5{plus_minus}1.0yr. From an approximately 1-yr-long study of another mixed source, where we compared the numbers of 1157-keV {gamma} rays from {sup 44}Ti to those of 1064-keV {gamma} rays from {sup 207}Bi, we determined the {supmore » 44}Ti half-life to be 62{plus_minus}5yr. From these two results, we have obtained a best value of 62{plus_minus}2yr for the half-life of {sup 44}Ti. The astrophysical implications of this result are discussed. {copyright} {ital 1998} {ital The American Physical Society}« less