Ranges in air of plutonium fission fragments as a function of their mass

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Material Information

Title:
Ranges in air of plutonium fission fragments as a function of their mass
Series Title:
United States. Atomic Energy Commission. MDDC ;
Physical Description:
3 p. : ill. ; 27 cm.
Language:
English
Creator:
Katcoff, S
Miskel, J. A
Los Alamos Scientific Laboratory
U.S. Atomic Energy Commission
Publisher:
Atomic Energy Commission
Place of Publication:
Oak Ridge, Tenn
Publication Date:

Subjects

Subjects / Keywords:
Plutonium   ( lcsh )
Fission products   ( lcsh )
Mass spectrometry   ( lcsh )
Genre:
federal government publication   ( marcgt )
technical report   ( marcgt )
non-fiction   ( marcgt )

Notes

Restriction:
"Date Declassified: March 6, 1947"
Statement of Responsibility:
by S. Katcoff and J.A. Miskel.
General Note:
Manhattan District Declassified Code
General Note:
"LADC-316"
General Note:
"Date of Manuscript: October 16, 1946"

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 005024616
oclc - 288524553
System ID:
AA00009291:00001


This item is only available as the following downloads:


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60


MDDC 812
LADC 316


UNITED STATES ATOMIC ENERGY COMMISSION


RANGES IN AIR OF PLUTONIUM FISSION FRAGMENTS AS A

FUNCTION OF THEIR MASS



by


S. Katcoff
J. A. Miskel



Los Alamos Scientific Laboratory


This document consists of 3 pages.
Date of Manuscript: October 16, 1946
Date Declassified: March 6, 1947


This document is for official use.
Its Issuance does not constitute authority
for declassification of classified copies
of the same or similar content and title
and by the same authorss.



Technical Information Division, Oak Ridge Directed Operations
Oak Ridge, Tennessee


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RANGES IN AIR OF PLUTONIUM FISSION FRAGMENTS AS A

FUNCTION OF THEIR MASS


By S. Katcoff and J. A. Miskel


It is possible to effect a partial separation of fission products by taking advantage of the varia-
tion in the range of fission fragments as a function of their mass. The same phenomenon can be
used to determine the mass numbers of previously unassigned fission products. In the experiments
reported here, the ranges in air of seven plutonium fission products have been determined and mass
numbers have been assigned to two of these. The straggling in the range has been determined for
each of these also.

The apparatus consists of a beryllium tube about 8 inches long and one inch in diameter, which
contains a thin flat plutonium foil at one end. Starting at about 4 inches from the plutonium, there
is a series of 14 zapon films (about 7 ?g, cm2 thick) spaced 1. 8-inch apart. The tube is ordinarily
evacuated to an air pressure of 12.0 cm Hg and then irradiated in a high neutron flux at the center
of the Los Alamos water boiler. The zapon films are so situated that all fission fragments in the
mass range being studied, which do not strike the walls of the tube, are stopped in the region of
the zapon films. They then diffuse to the nearest film where they remain. Nearly all of the stopping
material is air.

After irradiation, each zapon film (except the first and last), is radiochemically analyzed for a
few fission products. The activities found on each film are corrected to the same solid angle and
then plotted against distance of dry air traversed by the fragments, as in Figure 1. The distance


4
S__'4.2n Sb29

33n M Ce"



4-


0 0.2 0.4 0.6 0.8 4.0 4.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6
RANGE IN AiR (CM AT NTPI

Figure 1. Differential range curves.


MDDC 812










MDDC 812


S4.2h Sb9


0 +



0--------------------------------------------------



0 0.2 0.4 0.6 0.8 1.0 1.2 4.4 4.6 1.8 2.0 2.2 2.4 2.6 2.8

RANGE IN AIR (CM AT NTP)




Figure 2. Integral range curves.


is corrected to 76.0 cm Hg pressure, to 15"C, and account is taken of the thickness of zapon trav-
ersed. By integrating the area under these curves, integral range curves are obtained, as in
Figure 2. The straight portions of these are extrapolated to zero activity to give extrapolated
ranges.

So far, 8 fission products in the heavy group have been investigated. The extrapolated ranges
and widths at half height of the differential range curves are listed in the following table. The re-
sults for 85 m Ba'39 are considerably distorted because of diffusion of its 41 sec Xe ancestor
through, or around, the zapon films; therefore, they are omitted from the table.



93 h 4.2 h 77 h 60 m 43 m 12.8 d 33 h
Sb'" Sb'" Te' Te1" Te"' BaHO Ce"4

Extrapolated
range 2.317 2.296 2.253 2.232 2.210 2.108 2.084
cm

Straggling 13.2% 11.7% 11.9% 10.8% 9.6% 10.4% 11.5%


The results for 60 m Te'" and 43 m Te'" were obtained by analyzing for their 22 h I and 54 m I
daughters, respectively.

In Figure 3, the ranges are plotted against the mass numbers. A straight line has been drawn
through the points in the absence of a better approximation. Masses 132 and 134 were previously
unassigned, but it is now obvious from Figure 3 that they should be assigned to 77 h Te and 43 m Te,
respectively. The results reported here should be considered only as tentative because the experi-
ments are still in progress.





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MDDC 812


4"D


444


142 -_-- -


440 ------s--- --


438


436


434- -


132


130


128 -- -


426



2.08 2.40 2.12 2.14 2 6 2.L8 2.20 2.22 2.24 2.26 2.28 2.30 2.32

RANGE IN AIR (CM AT NTP)


Figure 3. Ranges of Pu fission fragments in air as a function of mass.


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UNIVERSITY OF FLORIDA


3 1262 08910 5505


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