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محمد
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MASTER
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Analytical Electron Microscopy
**Past and Present at
Oak Ridge National Laboratory
I Ylillnaich
Analytical electron microscopy, as opposed to research electron microscopy,
for the purpose of this talk, can be defined as the use of the electron
microscope and kindred techniques, such as electron diffraction, for the
purpose of providing primary knowledge of ultrastructure, not available
by other means, for projects or experiments done by researchers not connected
with a microscopy group. Microscopy of this type 18 frequently referred
to as a service operation; we prefer to call it, in keeping with its true
worth, research Assistance. Of the thirteen electron microscopes now at
Oak Ridge National Laboratory, the three, located with my group in the
Analytical Chemistry Division, provide research assistance to the Chemistry,
Chemical Technology, Instrumentation, Isotope, Operations, Physics, Reactor
Chemistry and Reactor Engineering Divisions. On occasion, support 18, or
has been given to divisions equipped with their own electron microscopes,
when an overflow occurred. These include the Biology, Health Physics,
Metallurgy, and Solid States Physics Divisions. To provide a background
for our work, a few historical highlights may prove interesting.
The group originated in New York City in 1943 as part of the Manhattan
Project. Its basic instrument was an RCA EMB, one of the first production
models, equipped with a diffraction lens. This was located in the basement
of Pupin Hall, the physics building, at Columbia University. The sad
fact that it was flooded out of this location by a week-end cloudburst a
*Research sponsored by the U. S. Atomic Energy Commission under contract
with the Union Carbide Corporation.
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month after it became operative, caused near consternation at the time, and,
on my part, an abiding suspicion of basement installed electronic equipment.
Moved to S. A. M. Laboratory, a renovated former Dodge showroom and garage
on Broadway above 125th St., it was reinstalled on the first floor. Here
it did stellar work, within its capacity, aiding in the development of
the barrier material that was to separate the uranium 180 topes in the then
unbuilt gaseous diffusion plant, K-25, at Oak Ridge, Tennessee. As I recall,
molded styrene-collodion, gold-manganin shadowcast replicas were used almost
exclusively in these studies. At one stage in the project, it was decided
to make use of the Polaroid Vectograph process, for presenting stereo
electron micrographs. Dr. William Ladd, and his wife, Margaret, had
made use of the method in their study of carbon blacks at the Columbian
Carbon Company in Brooklyn.
I was sent to them to learn the technique.
Their willingness to pass on their technical knowledge and adaptions of
this method, and their assistance in other ways since that time have
proved Invaluable. At the close of the New York project in 1946, I and
Dr. L. T. Newman, who had worked under Dr. Burton at the University of
Toronto on the first electron microscope made in North America, were
invited by the Union Carbide Company to set up a microscopy section at
K-25, Oak Ridge, Tennessee. We accepted, and shortly thereafter the RCA
EMB with suosidiary equipment was shipped to the Tennessee hills.
Unfortunately, a suitable location could not be found for it at the K-25
plant because of stray magnetic fields, line noise, and vibration problems,
60, on orders from the U. S. Army, still in charge of the overall project,
It was transferred to X-10, the Oak Ridge National Laboratory operated
then by the Monsanto Chemical Company. Newman and I went along with the
instrument. Space was made available in a wartime constructed wooden building
used by the Chemistry and Chemical Technology Divisions. Because doors were
narrow, ceilings low, and corridors winding, a hole had to be cut in a side
wall to get the instrument into the laboratory; to insure working mechanical
stability, free of vibration, a concrete pier was poured for the microscope,
resting on solid rock, and insulated from the surround with cork dust.
Once more in operation, we became involved in the study of beryllium and
beryllium oxide, the latter, a project originated by Dr. J. Farrington
Daniels. At that time the extreme toxicity of beryllium and Its compounds
had not been established. In retrospect, considering our handling methods,
Newman and I were and are very fortunate. The following year, Union Carbide
became prime contractor, under the A.E.C. for all Oak Ridge installations,
and soon plans began shaping up for a new modern laboratory complex at X-10
with ample provision for optical and electron microscopy. During the
interim period while the new facility was being designed and built, one of
the major projects at Oak Ridge National Laboratory was the development of
a chemical homogeneous reactor using aqueous uranyl sulfate as fuel. Our
contribution to this project was extensive corrosion stud les on the effect
of this solution, under a great variety of conditions, on various metals
including the 18-8 series stainless steels. Dr. Harold Urey, of the
University of Chicago, was a consultant in this investigation, and because
of the value he placed on stereomicrographs, due possibly to his interest
at that time in astrophysical studies of the moon surface, he insisted all
pictures of corroded surfaces, including both optical and electron micrographs,
be done in stereo. We had many interesting arguments over what were hill.
and what were valleys. Those of you who have ueed stereo techniques, are
aware that interpretation of this type micrograph can sometimes be very
misleading, especially if the viewer does not have well-developed stereo
vision.
With the new laboratory complete, we moved into what has been our
difficulties, such as having no drain or water lines for one darkroom, and
light leaks in all darkrooms, we were soon back in operation. A new Pl.ilips
100, ordered some months before, arrived, and was installed. The chief
feature that brought about its purchase was the need for selected area
election diffraction, a feature rot available in other microscopes at
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the time. Identification of the components of multi-layered corrosion
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films from metals of interest in nuclear engineering was then and has
continued to be of great importance. The lay-out of the section 18 shown
in the next two slides. (Slides 2 & 3). Darkroom traffic problems were
averted by including a negative development darkroom for each major instru.
ment where photographic processing was necessary. This feature has been a
timesaver, especially when many samples are procesned. Today we have a
Philips 75, a converted 100B and a 200, all in operation everyday. In
addition, for reflection diffraction work we use a modified G. E. Diffracto-
>
graph with a Philips gun, lens, and 100KV power supply. Shortly, the 100B
will be moved to a hot area to be employed exclusively in the investigation
of irradiated materials.
The problems of the past two years have been typical, and because of
their broad range of subject material, some of them may be of interest to
members of this group. I present these for your approval and comment.
Ant
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Metal Eating Bacteria?
The sample material in this study was an off white gelatinous scum removed
from the surface of the swimming pool or bulk shielding reactor. Optical
observation indicated the presence of rod shaped bacteria. Preparations
for electron microscopy showed chains formed of encapsulated bacillus
(511de 4). Spectrographic and wet chemical analysis indicated the bulk
of the gelatinous material was an aluminum compound. Electron diffraction
gave broad 11ne patterns identifying the mass as aluminum hydroxide. Because
aluminum was present in the reactor, we cultured miniecule amounts of the
gelatinous material in the presence of aluminum in the form of small wires.
After a few days, colonies, as seen in this slide, (slide 5) developed on
the wire. Droplets removed from these colonies were teeming with swarma
cells. (slide 6) After several weeks, examination of the wire, at colony
Bites, indicated cavitation attack. Our tentative conclusion was that
the bacteria belonged to the order chlamydobacteriales with a sheath
possibly composed of colloidal aluminum hydroxide. Of interest also, may
be the unidentified spirochete (slide 7) existing in a column, containing
a corrosion inhibitor, potassium dichromate, attached to the experimental
homogeneous reactor. The only bulk organic, present in this case, was a
teflon control rope for certain health physics equipment.
2.
Properties of Fission Product Aersol Produced
by Sver-heated Reactor Fuels
In connection with a safety program undertaken because of the increasing
number of commercial power reactors, we have, and are making studies of the
f188lon product aerbols produced by over-heated fuels. Emphasis has been
placed on finding a method for the collection of particles which will give
$
a true representative sampling. This slide (Slide 8) illustrates one phase
of this study. Here the nature of the particles collected by polypore filters
at position 16 are compared with particles collected directly on electron
microscope grids by an electio-static precipitator designed by us. The
modification was the insertion of a small diameter teflon tube to cut down
the throat diameter of the entry tube. As you can see, the physical nature
of the particles collected appear quite different.
The particles collected
on polypore or millipore filters are prepared for electron microscopy by
cutting the filters into 1/8" squares, vaporizing carbon on the collecting
surface, dissolving the filter in acetone, floating the carbon segments on
di-chlorethane, and capturing the squares on microscope grids. To date
after trying numbero!is collecting methods, including both electrostatic, and
thermal precipitators, and various types of impactors, we believe direct
collection on millipore or polypore
yields the most representative
samples. Identific'ition of particulate material has been made by selected
area diffraction, and we are are now attempting to use the new Kodak N.E.M.
gamma sensitive emulsion to differentiate between irradiated and non-irradiated
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particulates.
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3.
Air Pollution From Natural Sources
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Normally, in our thinking of air pollution; industrial gases, automobile
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exhausts, and the like are the chief offenders, yet it has been established
most conclusively by pollen induced allergies that nature is also a contributor.
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In this study by the Health Physics Division, it was determined that during
storms, the high potential existing between atmosphere and ground induces
the removal of a wax which covers pine needles. This wax becomes airborne.
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In this experiment (Slide 9) the nature of the material removed at various
potentials was studied. Particle replication was done with polyvinyl
alcohol-carbon, palladium-platinum shadowcast.
4. Radiation and Photolytic Effects on Silver Nitrate
A study was made of the effects of gamma and Alpha irradiation, and
photolytic reduction on aqueous silver nitrate. (81de 9) Dobeage was
supplied by Cobalt-60 for ganona, 20tassium-210, for alpha and a 100 watt
mercury lamp for photolytic reduction.
5. A Study of the Structure of Spherical Sol Gel Beads
Thoria sol gel beads of a size and shape suitable for being loaded into
fuel rods by vibratory compactions behind bulk shielding have been developed
at Oak Ridge National Laboratory. During the project many optical and
electron microscope studies were made to determine the effect of anionic,
cationic, and non-ionic surfactants. The next slide (Slide 10) shows the
physical nature of such a preparation where a non-ionic surfactant was
used. The surface and internal structure vary considerably from that
produced by cationic surfac-ants. (Slide 11).
The Corrosion of Niobium in Liquid Potassium
The surface structure and the nature of the film formed on niobium after
exposure to liquid potassium at high temperatures and oxygen pressure in
the pressence of certain contaminants were studied in detail. The
next slides shows the results from one sample.
(1)
The stripped film
appears to be a well-ordered mosiac type. (2) The diffraction pattern.
preferentially oriented No C. (3) The metal surface after stripping.Fax
film-carbon without shadowcasting were used for 1 & 2. 3 was shadowcast
with chromium.
The electron microscope has proved to be a most useful analytical toc. at
Ook Ridge Nacional Laboratory, and because of the wide deversification of
sample material, a constant challenge, a'u an ever interesting pursuit.
DATE FILMED
121/ 1 / 64




- LEGAL NOTICE
This report was prepared as an account of Government sponsored work. Neither the United
States, nor the Commission, nor any person acting on behall of the Commission:
A. Makes any warranty or representation, expressed or implied, with respect to the accu-
racy, completeness, or usefulness of the information contained in this report, or that the we
of any information, apparatus, method, or process discloved in who report may not Infringe
privately owned rights; or
B. Assumes any liabilities with respect to the use of, or lor damages resulting from the
use of any information, apparatus, method, or process disclosed in this report.
As used in the above, "personi acting on behall of tho Commission" Includes any em-
ployee or contractor of the Commission, or employee of such contractor, to the extent that
such employee or contractor of the Commission, or employee of such contractor prepares,
disseminates, or provides access w, any information pursuant to his employment or contract
with the Commission, or his employment with such contractor,

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