During the first part of March, 1945, I was still in London with
the war in Europe essentially over and my work there completed. Dr.
Robertson, a Theoretical Physics Professor from Cal
Tech, was in charge of the London O.S.R.D. office. He
was a well known expert in "General Relativity
Theory". I was having interesting
discussions with him regarding the apparent difference in
the effect of a kinematic acceleration and a gravitational acceleration
on a light beam crossing a laboratory room. The
factor of two difference in these two cases seemed to me to
be contrary to Einstein's dictum that all
accelerations should be equivalent when geometrical
factors were properly accounted for. I was being
told that in General Relativity E was not always equal to Mc2
and that I was a bit too stupid to understand the real workings
of the theory. I was finding it difficult to
accept these dicta and wondering how to readjust the
theory to rid it of this and other contradictions.
Meanwhile, I was trying to arrange
transportation home to the U.S.A. The British
felt I had done my job and they had no real urgent. reason to upset air priorities for my personal
convenience. Our London Embassy was taking
essentially the same attitude.
A break came in the form of a cablegram addressed to me
at the O.S.R.D. Office. It was
brief but had approval of the Manhattan Project.
The cable read "come at once, you know where, signed
I was not officially supposed to know about the Manhattan Project,
but most U. S. Physicists knew much more about it than General
Groves would have approved. Especially those of us
connected with the O.S.R.D. The
general never seemed to catch on that his secrecy
system worked rather well by courtesy and patriotism of the
American physical society. In fact, the leaks which
finally occurred were due to official inadequacy and
official scorn of Physicist suggestions about
'Louis' was Dr. Louis Alvarez, my long time friend from Cyclotron times
in the Lawrence Lab at Berkeley. 'You know where' was
the lab at Los Alamos, New Mexico.
Armed with this I was able to get space on a Pan Am flying boat
which was going the long way to avoid head winds with a load of
It took me seven days to reach New York, and another day to
get priority back to Boston. In Cambridge at
the Harvard Radio Research Lab, I found that
although I had already agreed to go the Collins
Radio Company ad Director of Research after my war duties
Dr. Sam Goudsmidt was offering me a position on
his project A.L.S.O.S. to retrieve German War science for the U.S.A.
I turned this down on the basis that I had no real knowledge of the German language. I probably
missed a great adventure and a very different
The officials of Harvard Radio Research Lab agreed to keep paying
my salary and I went as rapidly as I could to Santa Fe, New
There, Louis Alvarez and Ed McMillan met me and shepherded me
through the security requirements and up to the Los Alamos laboratory.
There I found many old friends and acquaintances. Louis
proudly showed me all the facilities just as he had at my first
arrival at M.I.T. for the radar development. At
M.I.T. he explained the "new to me"
principles of Radar and quickly exposed me to all
the new problems requiring solution.
My tour of Los Alamos lab facilities was a nostalgic repeat of
M.l.T. One of the first things at Los Alamos
was Louis showing me the huge walk-in safe, to which
he had the combination. This was
important because I saw materials in size and form entirely new
The safe contained spheres of precious metals in extremely pure
form available for neutron cross section work. (Alvarez,
with my friend and associate at Harvard Radio Research Lab,
Prof. Felix Block, had been a pioneer in the study
of spin polarized neutron beams. In
the Lawrence Lab in Berkeley, I often was in charge
of running the cyclotron to produce neutrons for their experiments.)
So, I held in my hand at that Los Alamos safe a 7 cm. sphere of
solid gold and a similar one of Platinum, a small one of Iridium, also one
of Silver and one of U238. But most
impressive, I held a hemisphere (about a half
critical mass) of Plutonium (worth at that time at
least 1 billion dollars).
was silver plated for handling since plutonium is a strong poison
as well as being appreciably radioactive. In
fact,. while the other spheres had the usual cold
feel of room temperature metals, the plutonium was
evolving enough energy from continued radioactive decay
to feel quite warm to the touch, a considerable contrast to
the other spheres.
This was an exciting show for me that I will never forget. Alvarez
had insisted that Robert Oppenheimer have me there as "the"
expert on electronic warfare to assess the vulnerability of
the tail warning radars that had been assembled to trigger the
bombs to be dropped on Japan. These were
arranged to give an exact height above ground for
the explosion. Redundancy was built
in a very wise precaution.
Housing was tight and I was assigned to share a room with Robert's
brother, Frank Oppenheimer, whom I knew casually from the
time at the Lawrence Cyclotron Lab.
I rapidly found several weak points about the proposed system including
poorly shielded I.F. amplifiers and a weakness for Chaff interference.
We worked these problems out of the system rapidly and
Robert Oppenheimer seemed pleased that I had come.
Several interesting incidents occurred during the short time I
was there before going to my new job at Collins Radio Co.
A series of experiments were under way to determine the critical
mass for U238 and for Plutonium. This
represents a very small energy release of about
0.164 ergs per second or 1417 ergs per day.
This is insignificant as heat energy but because of the
high initial particle energy may represent the destruction
of a significant number of protein molecules or
DNA-RNA gene chains per day. (Some
arguments have been proposed that this is the primary cause of human aging.)
This is a body dosage [Ref. (2) ] of
0.0002 rad. per day. Admittedly a small dosage (0.07 rad. per year). In
other terms about 10-4 microcuries of radioactivity in
an average human body.
(3) Nevertheless, it is about half the dosage
observed outside the Three Mile Island disaster, and
is a fact of life for everyone.
There is a minimum radioactivity dosage we all must live
with. Human biology is so variable,
however, that a sensible accounting of threshold
effects appears unlikely.
During my short stay of a few weeks at Los Alamos, there were
a number of interesting events. My old friend
from Lawrence Lab, Robert Cornoy, was there and
later was credited as inventor on one of the patents
of one type of fission bomb. I had last seen
him at Princeton University where he had been working with Robert
Wilson on the Wilson method Uranium isotope separation. Robert
was a great athlete. He lived back of the cyclone
fenced compound where the Los Alamos research was
centered. He decided it was
unnecessarily far from his house at Los Alamos to the front
gate of the compound where everyone presented credentials and
picture badges to get in to work. So, Bob found
somewhere a vaulting pole and vaulted over the fence
at the back each morning on the way to work. Since
he had no pole in the compound he was forced to go
home by going through the gate. After about three
months of this, he was caught and reprimanded because some
one finally noticed a discrepancy between the number
of people going in and out of the gate.
Strangely, years later in a McCarthy probe,
the F.B.I. said this pole vaulting episode proved Robert was