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MICROCOPY RESOLUTION TEST CHART
NATIONAL BUREAU OF STANDARDS - 1963
O2VB -
Cont: 660581
S
JUN 27 1966
THE U. S. ATOMIC ENERGY COMMISSION DEVELOPMENT
PROGRAM FOR HIGH-SPECIFIC-ACTIVITY ISOTOPES
FOR RESEARCH AND INDUSTRIAL APPLICATIONS
1.00
Physics
C. $ ....8
50
MIN
P. S. Baker
Isotopes Information Center
Oak Ridge National Laboratory*

RELEASED FOR ANNOUNCEMENT
IN NUCLEAR SCIENCE ABSTRACTS
I.
INTRODUCTION
-=
.
In the nuclear energy program there has been a continuing need for
increased specific activities of many isotopes for numerous applications.
The requirement for "point" sources has never been completely satisfied.
For heat sources a maximizing of activity concentration is usually highly
desirable. For tracer work mure nuclides are often more effective than
impure sources. To these ends the U. S. Atomic Energy Commission is
sponsoring a number of development programs directed toward making avail.
able very high-specific-activity radioisotopes produced by fission, by
reactor activation, and by charged particle bombardment in accelerators.
The USAEC has considerable capability for producing large quantities
LES
of a wide variety of high-specific-activity ralioisotopes. However, for
the past several years, in keeping with the Atomic Energy Act of 1954,
the production of many isotopes (33 as of May 1, 1966) has been assumed
by private industry in the U. S. (Table I). To take the place of routine
production, many of the facilities and technical personnel are redirecting
their efforts into special develcpmental programs. It is the purpose of
this paper to indicate some of these programs and the isotopes involved.
In general, high-chemical-purity as well as high-isotopic-purity
targets are usually preferred for radioisotope production in both reactors
and accelerators since 1) more efficient use of neutrons or charged-particle
beams results; 2) higher specific activities (or activity concentrations)
T
.
.
1
result; and 3) unwanted side activities, resulting from the activation of
*Operated by Union Carbide Corporation for the U. S. Atomic Energy Commission.
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WITHDRAWN ISOTOPES
124 Sb 12556
109ca 115ca
58c0b4cu
55fe595€
32P 426
859 1135n
7EAS 77AS 82Br 45ca
115mca 142ce 234cs 51cr
198A4 199A4 2251 1311
1401a 197Hg 203H8S90
755e 220mAg 24Na 8558
652
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TEGAL NOTICE
This report ni prepurod u wa N.count of Government sponsored work. Neither the traited
Statos, por the Commission, dor hay person ucting on behalf of the Comaalaston:
A. Wekas any warruty or represcatation, exprused or implied, with respect to the accr-
racy. coapstoners, or watulacan of the laformation contatood ta dhuis report, or this the ne
of any information, appuntos, method, or proces daclound to fide report may not betstaga
prinitaly mond rietta; or
8. Anremos uv labaudies with respect to them was of, or for damage maaltter f.om the
une of any buformation, uuritus, method, or process discloud ba the reports
As und in the abon, "parroa acting a balall of the Countertop" lacluded my mo-
plogna or contractor ata Commisson, or employee of cha anatracte, to the atunt that
pesca saplogue or cotractor of the Commission, or maployo al rock contactar propria
diumenabrates, or provides ascolto, my taformadoa permanent to Ho caplogans or contract
with the Commissia', or to amploymeat with such contracto .
1
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other isotopes of the target element, are reduced or almost entirely elimi.
nated. However, the added cost of an enriched target must be balanced
against these advantages as well as against the economic advantages resulta
ing from more eficient use of neutrons or charged particles.
II. REACTOR-PRODUCED ISOTOPES
Among the reactor-produced isotopes involved in developmental efforts
are 60Co, 244Cm, 192 Ir, 198Au, several fission products, and a number of
isotopes not ordinarily obtainable, or available only as accelerator-
produced products.
A. Cobalt-60
The desirability of high-specific-activity 6oCo for point sources
18 well recognizai. Buü its use for heat sources has only recently been
pursued (1-3). Specific activities up to 700 c/g are currently being
produced in the high-flux (4 x 1025 n/cm2.sec) (4,5) reactors at the Savan-
nen River Plant of the USAEC, although typical production is 50-500 c/g.
Power source outputs of up to 60 kw(e) are contemplated. Since SRO has
the capacity for producing in excess of 450 kw/t) per year as merely inci-
dental production, and a stated (6) capacity of many tens of megacuries
per reactor per year if the reactor charge is designed for 60Co production,
such sources are not at all unreasonable. The total capacity from power
reactors is hundreds of megacuries, equivalent to several thermal mega-
watts (7). Table II shows some physical data for 60Co sources.
A possible advantage of 80Co over other potential heat-power sources
is econocy in expense and development time. There are also some advantages
(characteristic of isotope sources in general) over nuclear reactors as
space-power sources: 1) greater reliability resulting from the elimination
of reactor-associated problems of control, startup, and fuel failure;
ET
2) elimination of neutron activation of coolants and space stations;
-
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.
Talle I. PHYSICAL DATA FOR 60CO SOURCES
Output, kw
Diameter of
(15% Efficiency).
Amount Spherical
Electrical Thermal Mc l b Source, in.
67' 4.3 23.8
13.0 71.5 7.55
.60 400 26.0 143.0 9.5
.
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10
67
5.2
5.2
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3) reduction or elimination of problem of coolant freeze-up, since source
cannot be shut down.
A limitation to the specific activity of BºCo 16 the nickel content
of the source material. As shown in Fig. 1, both stable Boni and stable
FidNi are produced during the activation of 5900, and the BONI continues
to "grow in" due to Boco decay after irradiation has ceased (8). The
nickel content at the completion of irradiation is, of course, a function
of the reactor neutron flux level and the irradiation time; ultimately it
is a function of decay time. For example, a 600 c/g source which contains
8% nickel at discharge would contain ~ 34% nickel when the source had
decayed to an activity level of 300 c/g.
A technique developed at ORNL for alleviating this problem involves
dissolving the source, removing the nickel as the dimethylglyoxime complex,
electroplating the resiäual cobalt into mercury, and then hot-die pressing
the Hg-Co product to squeeze out the mercury and leave a metallic cobalt
pellet.
.
An interesting extension of this technique permits the use of cobalt
oxide as the target material for irradiation, since the activated product
can be dissolved, freed of nickel, and then electrolyzed to give a metallic
cobalt source.
B. Curium-244
Also made possible by the high fluxes at Savannah River is the
production of ~ 3 Kg 244 cm (9-11) from 239Pu by successive neutron capture
(Fig. 2). Curium-244 has a half-life of 18 y and a specific power of
2.65 watts/8, making it suitable for thermionic and thermoelectric power
T
!
-
conversion and hence for use in isotopic power sources. Several stages
siya
and intermediate separations are necessary.
In the first stage the 239 Pu
charge is converted to higher isotopes.
In the second stage, the isotopes
.
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ORNL-DWG 65-2238
60mco
.
I.T. > 99 %
15
Ant
ray 11. T. >99%
59c0n; Yn 60com, Y 6100
2242
60NI INI
Fig. 4.1. Production of 60Co from $9 Co.
.
.
.
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PRODUCTION
CURIUM-244
Fig. 2.
240 *
Fission
40P
• 24²c
112 h -
2AA Amst
, 244nu
Fission
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243Arn
on
(13 h
243Y *
24P,
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of plutonium are converted to a mixture of 242 Pu, 243Am, and 244cm.
Succeeding stages involve a series of steps designed to optimize the burnup
of 242 Pu and avoid burnup of both the 243 An intermediate product and 244 Cm
final product. A rather detailed chemical procedure assures recovery of
-
-
- -
the plutoni un and separation of the americium and curium. The final curium
product is ~ 95% 244 cm.
C. Iridiun-192
The usual specific activity for commercially availabla 192 Ir varies
froin 100-200 c/g. Interestingly enough, one reason for this low value is
the high cross-section of the 192 Ir target (%100 b). The usual target
material is massive iridium metal, and the high neutron absorption at the
surface precludes any appreciable activation near the center of the piece
of metal. The result is a source with very high surface activity, but
-
-
-
-
-
rather low avera e activity.
AT ORNI, F. N. Case has developed a procedure to overcome this, which
consists of irradiating thin specimens of 191 1r to obtain specific activi.
ties of ~ 1000 c/8, then fusing the wire or foil into a dead to provide
an excellent "point" source.
D. Gold-1.98
High-specific-activity 198Au can be obtained by wrapping the 197 Au
target in cadmium prior to irradiation, to absorb thermal neutrons and
minimize the 198Au(n,r) 199 Au reaction. It is possible, then, to capital-
ize on the 4-ev rescnance-capture cross-section of the 197 Au(n,r)298 AU
reaction without any buildup of 199Au impurity. Figure 3 shows the neutron
P3
cross-section curve for the activation. A FORTRAI program (12) has been
set up to evaluate a large number of such reactions.
E. Fission Products
F:
7
For a number of years, the USAEC has been sponsoring programs
directed toward the development of methods for separation of gross quantities
ORNL-DWG 65-14434

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cf high quality long-lived fission-product isotopes. The work with 137Cs,
90Sr, 147pm, and 244 Ce is well known. In particular, the work with 147 PM
to give a product with near theoretical specific activity and extremely
high chemical purity has been exemplary (33). However, development work
in the areɛ of smaller quantities of short-lived fission isotopes has also
been going on.
1. Iodine-131. Several years ago an economic study was made to
compare four methods for the preparation of 1311: 1) from normal uranium,
2) from enriched uranium, 3) from normal tellurium (34% 130TE), 4) from
enriched tellurium (96% 1301e). The fission-product iodine from enriched
uri nium turns out to be not only cheaper to make, but to have a specific
activity higher than that by any of the other methods. (However, use of
99% 130Te would give a comparable, but more expensive, product.) For a
4-week irradiation, the percentage of 1311 is nearly 4 times that from
nornal tellurium. Furthermore, other fission-product isotopes can be re-
covered as by-products (14). For shorter ir. di&tions, of course, the
advantage is not so great. The process involves dissolution of the
A1_235U target in NaOH, acidification of the resulting solution with
H2SO4 and sparging with air to convert the iodide to elemental iodine and
to sweep the Iz into NaOH-Na2S03 traps, then separation of the resulting
iodide by sorption on platinum.
2. Xenon-133. Associated with the 1311 process discussed above is
the separation of 133 Xe during the NaOH dissolution of the All-235ų target
(15). The gas is passed through liquid nitrogen traps and a sulfuric
acid scrubber and is collected on activated charcoal cooled in liquid
nitrogen. In a normal a un, 300 curies of high-purity 133 Xe can be collected
in the same run producing 200 curies of 1321.
3. Krypton-85. The usual fission-product 85Kr contains < 6%
of the radioactive species; a typical analysis is 83Kr: 14%; 84Kr: 299" ;
-1).
85Kr: 6%; BeKr: 51%. However, for many contemplated applications (16),
a concentration of 40-50% is highly desirable. ORNL 18 currently enrich-
ing 85Kr by thermal diffusion and, on an experimental basis, expects to
prepare ~ 4000 curies/yr of ~ 45% 85Kr.
F. Non-Fission-Produced Inert-Gas Isotopes
In addition to fission-product 95Kr and 133xe, small quantities
of three other Inert-gas isotores have recently become feasible (17).
1. Xenon-13īm. This Isotope was prepared by Irrad:lating elemental
12812 for 3 months; the reaction 18
1281(n, y)2301 12:5 h 130 xeln, y)231mxe.
-
-
The product decays with a 12-de.y half-life by IT to 132 Xe.
2. Xenon-129. Normal 12712 18 irradiated for one month and 129m/e
-
-
results:
-
-
1271(n,y) 1281 2:5 m 128xe(n,y)229mxe.
The product decays with an 8-day half-life by IT to 128xe.
3. Krypton-79. Krypton-78, enriched to w7% (natural abundance, 0.35%),
is irradiated for 3 days to produce 78Kr. It decays to 79Br by positron
emission.
G. Phosphorus-33
The availability of suitable 33P (free of 32p) depends essentially
on the availability of the highly enriched stable 338 target (recently,
82% 335; natural abundance 0.74%). This makes possible high specific
activity, high purity 337.
H. Others
Only a few neutron-deficient isotopes are produced in reactors.
F
-
One that shows some promise of success is 1261 by the 127I(n,2n)1261
reaction. The specific activity can be greatly enhanced by using the
.
.
W
12-
Szilard-Chalmers effect. Another reactor-activated neutron-deficient
isotope 18 37 Ar (decays by electron capture), prepared by the (ngo)
reaction on 40ca.
A number of other reactor-production methods are being studiet for
1sotopes not ordinarily available, or available in low yield only by
accelerator irradiations. In general, transmutation reactions as well
as enriched targets are being emphasized in order to give high yields of
high-specific-activity products. Table III 118ts several of these 18otopes
-
-
-
which have been produced successfully. Others have been reported else.
where (18,19).
The 151 Sm, which can be prepared from either normal or enriched 150Na
targets, is potentially a very useful isotope, since it decays with a
90-year half-1.1-e, giving off 22-kev y rays and 76-kev Ba particles.
III. ACCELERATOR-PRODUCED ISOTOPES
Neutron-deficient isotopes are prepared by a number of reactions, most
of which occur in accelerators such as cyclotrons, e.g., (1,n), (p,pn),
(p,2n), and (a,n). Charged-particle reactions have an advantage over most
neutron-induced reactions in that transmutations result and the products
can be separated carrier free. Moreover, energies of the bombarding
particles can be controlled to give selective reactions. Unfortunately,
yields are usually lower than for neutron-induced reactions. However,
there are some instances where no neutron-induced reaction is available
*
for a particular product (e.g., 7Be and 48V). In these cases, relative
yields are of no significance, of course. In other cases, the relative
importances of yield and specific activity must be evaluated for any
particular nuclide.
Early work with cyclotron isotopes was reported by Martin et al. (20).
.
-
-
.
.
Since then, a considerable amount of effort at ORIIL has gone into the
-.
development of improved techniques for production of carrier-free
73
+
-
-
.
. .
- -
-
.
-
-
.
- -
-
ill : SPECIAL, REACTOR ISOTOPES
sre(n,6)37Ar 82Ni(n,a)58Fe
1 43 Ca(n,p)43K
745e(n,p)74AS
58Ni(n,p)58C0 84 Sr(n,p)84 Rb •
59coln,p)59 122re(n,y) 123mme
1981a(n,x)24014(n,r)24212 252 ce
150xa(n,r)251.pa 251 pm 1545m
-
:
:
--
-
-
-
-
-14-
cyclotron products.
The results of some of this work have been reported
by Pinajian (18,21). Table IV lists information about a few of these
isotopes. It will be apparent that a nuclide such as 52Cr, already capa
-
-
-
**
able of production as a neutron product with a specific activity > 1000 c/8,
..
.
**
3
.
.
will have an even higher activity when prepared by the transmutation of
-
-
-
*
-
-
-
vanadiun.
-
-
- - .
-
...
..
IV..
IMPROVED RADIO::SOTOPE GENERATORS
v
.
--
-
A radioisotope generator, or "milker," has the property of providing, .
continuously, small quantities of a daughter by separation from a parent,
---
I
The purity depends upon a number of jactors, and can be greatly enhanced
by proper choice of parameters.
Both Brookhaven National Laboratory and ORNL have been working on the
development of new isotope generators as well as on improvements in the
more conmonly used generators (Mo-99MTc; 132Te-1321; 995r-987; 95Nb_852r;
877-87m$r; etc.). BNL has reported on much of the early work (22,23) and
both BNI and ORNL have covered more recent work (24-28). Table V lists
some of the newer or improved generators being worked on by BNL and ORNL.
A report of the 44Sc generator should be available shortly, the tellurium
:
.
.
Y
-:
*
generators are being reported on elsewhere at this conference, and the
42K generator needs a good source of 42Ar.
i tauern.,
L
the
An interesting article by Brucer* (29) considers 118 possible generators.
V. FUTURE WORK
The availability of the High Flux Isotope Reactor later this year for
activations at fluxes > 1025 n/cm • sec will open up a whole new field of
development work, from economic considerations as well as from the stand-
point of better products. Research quantities of all radioisotopes can
are in
be produced with activities approximately ten times those now available;
*Former Director, Medical Division, of AEC's Oak Ridge Institute of Nucle:10
Studies.
.
15
53 d
TiO2
y ab's TT. EXPERIMENTAL YIELDS IN ORIL 86-INCH CYCLOTRON
Nuclide Half-life Target Yield, mc/hr
? Be
Li
16.1 à
27.8 a
54Mn 314 d.
2.6 y Mn
267 a Ni
245 a cu
4By
53 Cr
V.
54 Cr
Tc4
55Fe
5700
6521
84 RD
33 a
Kr
2231.
13
223 Te
ki. "
fi
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.
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1.16
Tarbie Ď POTENTIAL MILKING SYSTEMS
Daughter Half-life Parent
BNL 4480 4.0 h 44T1
1318Te
25 m
131mme
67 m
1272 Te
9.3 h
127me
42K 12.4 h
1288Te
220mTe
Half-life
~100 y
1.2 &
33 d
105 d
35 y
11.6 a
42 Ar
131 Ba
ORNL
13108
288 Re
113mIn
9.7 a
17 h
1.75 h
188W
69 d
1135n
118 d
-17-
those isotopes with very long half-lives are particularly interesting,
since activities are normally rather low (e.8., 36c1, 45ca, 55Fe, 63N1,
208ca, 110mAg, 113sn, 12556, 152Eu, 154 Eu, 270m, and 20471).
A few of the short-lived 1sotopes will also become more useful, since
the higher initial activities will allow an additional decay of several
half-lives (e.8., 42K, 24Na, 64cu, 724a, 187W, 184Ir, 18712Hg).
Also of potential significance 18 a "hot" calutron -- an electro-
magnetic separator for separating and concentrating appreciable quantities
of radioisotopes.
Its feasibility has been demonstrated, and it 18 hoped
that such a imit may become a reality in the next few years.
.
E
.
.
References
(1) DEXTER, A.H., 60 Co Heat Sources for 10-60 kwle) Generators,
USAEC report DP-974, Savannah River Laboratory (July 1965).
(2) KING, F.D.R., and ANGERMAN, C.L., Large-Scale Co-60 Heat
Sources, USAEC report CONF-660305-14, Savannah River Laboratory
(February 1966).
(3) JOSEPH, J.W., Jr., ALLEN, H.F., ANGERMAN, C.L., and DEXTER,
A.H., Radioactive Cobalt for Heat Sources, USAEC report DP-1012,
Savannah River Laboratory (October 1965).
(4) SMITH, J.A., HENNELLY, E.J., ICE, C.H., and. ALLEN, H.F., Isotope
Production in á Savannah River Reactor at Flux levels above 1015
n/(cm2 sec), Trans. Amer. Nucl. Soc. 8, No. 1 (1965).
(5) CRANDALL, J.L., Comp., The Savannah River High Flux Demonstra-
tion, USAEC report DP-999, Savannah River Laboratory (June 1965).
(6) ALLEN, H.F., Cobalt-60 Production at Savannah River, Nuclear
News 1, No. 6 (1964) 22.
(7) AEBERSOLD, P.C., USAEC. Advances in Radioisotope Production and
Utilization in Science and Industry, P/196. Conf. Peaceful Uses of
Atomic Energy, Geneva (August 31-September 9, 1964).
(8) RUPP, A.F., Cox, J.A., and BINFORD, F.T., Radioisotope Produc-
tion in Power Reactors, USAEC report ORNL-3792, Oak Ridge National
Laboratory (May 1965).
(99) OVERBECK, W.P., ICE, C.H., and DESSAUER, G., Production of
Transplutonium Elements at Savannah River, USAEC report DP-1000,
Savannah River Laboratory (November 1965).
(96) MCDONELL, W.R., SMITH, P.K., STURCKEN, E.F., LIVINGSTON, J.T.,
THOMPSON, M.C., and MOSLEY, W.C., Jr., Curium-244 for Radioisotopic Heat
Sources Work at the Savannah River Laboratory, E. I. du Pont de Nemours
and Co. (February 1966).
(9c) GROH, H.J., HUNTOON, R.T., SCHLEA, C.S., SMITH, J.A., and
SPRINGER, F.H., 2446m Production and Separation -- Status of the Pilot
Production Program at Savannah River, Nucl. Applications 1 (August 1965)
327-36.
(10) FERGUSON, D.E., ORNL Transuranium Program – the Production of
Transuranium Elements, Nucl. Sci. Eng. 17 (1963) 435-7.
(11) RUPP, A.F., Reactor By- Products, from Reactor Technology
Selected Reviews (1964+) 477-528, L.E. Link (Ed.).
-4.
19
(12) FRIEND, C.W., and KNIGHT, J.R., ISOCRUNCH – Modifications to the
CRUNCH Program for the IBM 7090, USAEC report ORNL-3689 (January 1965).
(13) ORR, P.B., PRESSLY, R.S., and SPITZER, E.J., Evidence of the
Absence of Long-Lived Isotopes of Promethium from Fission of Uranium,
and the Purification of Promethium for the Establishment of a Primary
Spectrographic Standard, USAEC report ORNL-3631 (January 1965).
(14) CASE, F.N., Coordinator, ORNL Radioisotopes Procedures Manual,
UEAEC report ORNL-3633 (June 1964).
(15) CASE, F.N., and ACREE, E.H., Large Scale Preparation of High
Purity I-131 and Xe-133 by Sorption Techniques, USAEC report ORNL-3840
(January 1966).
(16) CARDEN, J.E., Preparation, Properties, and Uses of Kryptonates
- Chemical Analyses, Isotopes and Radiation Technology 4, No. 3 (Spring
1966) in press.
(17) ACREE, E.H., Preparation of Xenon-131m, Xenon-129m, and
Krypton-79, USAEC report ORNL-3839 (May 1966) in press.
(18) PINAJIAN, J.J., ORNL 86-In. Cyclotron, Radioactive Pharmaceuti-
cals (May 1966) (AEC Symposium Series) 143-54.
(19) O'BRIEN, H.A., Jr., Reactor Production of Carrier-Free Manganese-
54 from Natural Iron, Intern. J. Appl. Radiation Isotopes 16, No. 12
(December 1965) 747-9.
(20) MARTIN, J.A., CROMPTON, R.S., MURRAY, R.L., and RANKIN, D.,
Radioisotope Production Rates in a 22-Mev Cyclotron, Nucleonics 13, No. 3
(1955) 28-32.
(21) PINAJIAN, J.J., Production and Medical Uses of 67Ga, Bega, and
720a, Isotopes and Radiation Technology 1, No. 4 (1964) 340-3.
(22) Brookhaven National Laboratory, Processed Isotopes Available
from Brookhaven National Laboratory (1960).
(23) GRHINE, M.W., DOERING, R.F., and HILLMAN, M., Milking Systemy:
Status of the Art, Isotopes and Radiation Technology 1, No. 2 (1963-4)
152-4.
(24) HILLMAN, M., Isotopes and Raliation Technology 2, No. 1
(1964-5) 92.
(25a) RICHARDS, P., Nuclide Generɛ.tors, Radioactive Pharmaceuticals
(May 1966)(AEC Symposium Series) 155-63.
2
.
.
.
02
I
(250) HILIMAN, M., GREENE, M.W., BISHOP, W.N., and RICHARDS, P.,
Production of y87 and a Sr87ın Generator, Intern. J. Appl. Radiation
Isotopes 17, No. 1 (January 1966) 9-12.
c
.
-
---
9
.
*
-
.
STE
.
(26) PINAJI.AN, J.J., The Evaluation of the Hydrous Zirconium Oxide/
Nitric Acid System for Use in a 98M0-9510TC Generator (May 1966).
(27) PINAJIAN, J.J., A 137Cs-137 Ba Isotope Generator (Submitted for
publication to J. Chem. Ed., April 1966).
(28) PINAJIAN, J.J., An 1321 Generator for 011 Soluble Systems (TO
be submitted for publication in intern. J. Appl. Radiation Isotopes).
(29) BRUCER, M., 118 Medical Radioisotope Cows, Isotopes and Radia-
tion TechnolocL 3, No. 1 (Fall 1965) 1-12.
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