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MICROCOPY RESOLUTION TEST CHART
NATIONAL BUREAU OF STANDARDS – 1963
ORN 0-1900
Conta651118-1
MOV 1 5 1985
RNL - AEC - OFFICIAL
Che Measurements for Use as Standards
in the Energy Range 800 to 1200 keV

**
J. H. Hamilton, S. R. Amtey,* B. van Nooijen** and A. V. Ramayya,
Vanderbilt University, Nashville, Tennesseet
and
RELEASED FOR ANNOUNCEMENT
IN NUCLEAR SCIENCE ABSTRACTS
J. J. Pinajian
Oak Ridge National Laboratory,++ Oak Ridge, Tennessee
In the study of nuclear energy levels, conversion coefficient
measurements have played an important role. With the development of
solid state detector systems for determining conversion coefficients,-)
such studies will be made on a more routine basis in many nuclei. The
use of solid state detectors, as well as some other systems, depends
on the availability of well determined conversion coefficients for use
as calibration standards. A literative search was made for conversion
coefficients measured with an accuracy 5%. Above 662 kev, only one
at 810 keV 18 known that accurately. Additional accurate conversion
coefficients of transitions with hv> 662 keV are needed for calibration
standards.
*on study leave from Tata Institute of Fundamental Research, Bombay, India.
**NSF Senior Foreign Scientist on leave from Delft Technical University,
Delft, Netherlands.
twork supported in part by a grant from the National Science Foundation.
** Research sponsored by the U. S. Atomic Energy Commission under contract
with the Union Carbide Corporation.
LEGAL NOTICE
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This report mo prepared as an account of Government sponsored work. Neither the United.
statai, nor the Commission, nor any person acting on behalf of the Commission:
A. Maken any warranty or reprosentation, expressed or implied, with respect to the accu-
racy, completeness, or usefulness of the information contained in this report, or that the vso
of any information, apparatus, method, or proceso disclosed in this roport may not Infringe
privately owned righto; or
8. Aonumes any liabilities with respect to the use of, or for damages resulting from the
Un of any information, apparatus, method, or proces diaclovod in the report.
A. und in the abovo, "person acting on behalf of the Commission" Includes any on-
ploys or contractor of the Commission, or employee of such contractor, to the extent that
ouch employs or contractor of the Commission, or employee of such contractor prepares,
disseminates, or provides access to any information pursuant to his employment or contract
with the Commission, or his employment with such contractor,
.
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The simple, long-lived decays of 54Mn, 88y, and 657n have sigh- ::
energy gamma rays which are used often for energy calibration and/or
for line shapes in unreveling gamma spectra. Thus they provide ideal
additional conversion coefficient standards. The K conversion coefficients
of the 2+ to 0+, 835.0, 3- to 2+, 898.2, and 5/2- to 3/2-, 1115.6 kev
transitions in"54Cr, 88sr, and 65Cu were measured by the internal-external
conversion (IEC) method.
The 54Fe(n,p)54Mn reaction was used for the production of 54Mn
activity. The 54mn was isolated from the target material by solvent
extraction of the iron and then was further purified by the use of anion
exchange chromatography. The 88y and 85zn were produced in the ORNL
86-Inch Cyclotron using the 885r(pen)Bey and 65cu(p,n)65zn reaction,
respectively. The B8y was isolated by radiocolloidal separation and
further purified by anion exchange chromatography and 5zn was isolated
by anion exchange chromatography -Each-of-the activities was carrier.
free and of very high chemical purity. Each source was liquid deposited
on aluminum coated Myler. A uranium converter, 3.71 $ 0.04 mg/cm,
was used. The f factor was calculated in Stockholm. The correction
for possible photoelectron scattering in the converter 18 less than 1%
in this work.
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The internal and external conversion lines of the 835.0 keV tran-
sition in 54Cr were each measured 5 times. Table 1 presents the results.
For comparison with theory, the conversion coefficients of Rose were
extrapolated to Z = 24. The photoelectric cross-sections of Pratt, et al.")
and of Hultberg, et al) were used. The assigned uncertainties in f, and
Tre are 2%. In other experiments at 605 keV and above, it was shown that
the accuracy of the IEC method is 5% or better.?)
The internal and external conversion lines of the 898.2 keV transition
in 685r were each measured twice. The K and L + M + internal conversion
lines are sufficiently separated at this energy and 2. Table 1 gives the
results along with the El conversion coefficients of Rose' and of Sliv
and Band. 8)
The internal and external conversion lines of the 1115.6 kev
transition in 65Cu were each measured 3 times. The K and L + M + internal
conversion lines were sufficiently separated. Table 1 presents the results
and the theoretical Ml and E2 values."
The accuracy of these conversion coefficients 18 sufficient to
qualify them as useful calibration standards in the determination of
spins, and parities of nuclear levels.
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References
1. H. T. Easterday, A. J. Haverfield and J. M. Hollander, Nucl. Instr.
and Methods 22 (1965) 333.
2. B. van Nooijen and J. N. Hamilton, Internal Conversion Processes,
ed. J. H. Hamilton, Academic Press, New York, 1965, Appendix 4.
3. E. F. Zganjar and J. H. Hamilton, to be published.
4. R. Pratt, R. D. Levee, R. C. Pexton and W. Aron, Phys. Rev. 134,
(1964) A898.
5. S. Hultberg, B. Nagel and P. Olsson, to be published.
6. T. Katch, M. Nozawa, Y. Yoshizawa and Y, Koh, J. Phys. Soc. Jap,
13 (1958) 1419.
7. M. E. Rose, Internal Conversion coefficients, North-Holland Publishing
Co. Amsterdam, 1958.
8. L. Sliv and I. M. Band, Alpha-, Beta- and Gamma-Ray Spectroscopy .
ed. K. Siegbahn, North-Holland Publishing Co., Amsterdam, 1965.
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Table 1
YA
f
O
Exp.
Oy Theory
Isotope:
hv (kev)
(x 108)
(x 108)
w..
2127)
DOMO
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24 C2.54
..7.34K
224 10*
301 21
166.4 £ 6.6
835.0
898.2
1115.6
:
2747)
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3887.08
282
182
290465
159
· "The K/L + Mt ratio of ref" was used to obtain are
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