||[U.S.A.] Pluto discovered by C.W.Tombaugh. (see
||[Germany] Discovery of radiation which penetrates a
leadblock by Walter Bethe. (Received 1954 Nobel prize.)
||[France] Proton emission from beryllium irradiated by
alpha-ray, discovered by Frederick Joliot and Irene Curie.
||[England] Neutron discovered by James Chadwick,
verifying Rutherford's Baker Lecture. (Received 1935 Nobel prize.)
||[U.S.A.] Cyclotron developed by Ernest Orlando Lawrence
and M.S.Livingston of California University, 27.5 inch size developing
one million electron volts. (Received 1939 Nobel prize)
||[England] Conversion of element by John Douglas
Cockcroftand Ernest Thomas Sinton Walton. Emergence of helium by
irradiating highspeed proton to lithium, based on Gamow's tunnel effect.
(Received 1951Nobel prize)
|1932. 8. 2
||[U.S.A.] Positron discovered by Carl David Anderson,
detecting a cosmic-ray shower using a cloud chamber. (Received 1936
||[U.S.A.] Deuterium discovered by Harold Clayton Urey.
(Received1934 Nobel prize)
||Albert Einstein seeks refuge in Belgium.
||[Germany] Adolf Hitler becomes the Fuehrer of the Third
||Leo Szilard escapes from Berlin to Vienna.
|1933. 4. 7
||[Germany] Promulgation of anti-Judish law by Nazi
||L. Szilard moves to England.
|1933. 9. 9
||A. Einstein moves to England.
||[England] Idea of chain reaction via neutron by
L.Szilard.He took a hint on the Times' report of Rutherford's lecture
about atomic transition. The idea of atomic bomb was patented in 1934.
The patent was transferred in secret to England's navy, 1936.2.
||Albert Einstein moves to U.S.A.
||The 7th Solvay meeting. M. Curie, E. Rutherford, N.
Bohr,L. Meitner, W. Heisenberg, W. Pauli, E. Fermi, J. Chadwick, G.
Gamow, F.and I. Curie, P.M.S. Blackett, R.E. Peierls. In Brussels. On
the structure of proton.
||G. Gamow escapes from Soviet Union, seeks refuge in
U.S.A. after the Solvay meeting.
||[Italy] Weak interaction and beta-decay theory by Enrico Fermi.
(Received 1938 Nobel prize.)
||Rudolf Ernst Peierls seeks refuge in England.
||[Germany] Project of rocket development; by v.Brown.
||[France] Artificial radioactivity. F. and I. Curie
detected radioactive phosphorus and positron by means of a Geiger
counter after irradiating aluminum with alpha-rays from polonium.
Blessed by M.Curie who was suffering from leucaemia caused by
irradiation. (Recieved 1935Nobel prize)
||[Italy] Transuranic elements assumed by E.Fermi based
on experimental results of irradiation of proton from radon and
beryllium to uranium
||[Germany] Possibility of nuclear fission proposed by
Ida Noddack, a feminine scientist, not attracting attention.
||[Italy] Radioactivity induced by slow neutrons
discovered by E.Fermi.
||[United Kingdom] Hydrogen fusion reaction discovered by
Marcus Oliphant and Paul Harteck, Cavendish Laboratory. Bombarding
hydrogen2-deutreum, in the form of concentrated heavy water- with
||[U.S.S.R.] A small cyclotron was built by Abram I.
Alikhanov and Igor Kurchatov. The first cyclotron operating outside
||Hans Albrecht Bethe seeks refuge in U.S.A.
||Edward Teller seeks refuge in U.S.A.
||Eugene Paul Wigner and Johann Ludwig von Neumann seek
refuge in U.S.A.
||[Japan] Meson predicted by Hideki Yukawa. Pi meson is a
hadron involved in alpha-decay and nuclear force. (Received 1949 Nobel
||[Denmark] Liquid-drop model of atomic nucleus proposed
by Niels Bohr.
||[England] Energy production by conversion of hydrogen
to helium proposed in a lecture by Francis William Aston.
Ｅ＝ｍｃ2. A glass of water is enough for a full speed cruise
of the Queen Mary in Atlantic Ocean.
||[Germany][SPAIN] Guernica. Indiscriminate bombing by
German air force assisting Franco army. Protested by P. Picasso in
||[U.S.A.] Cyclotron with 60 inches diameter and 220 tons
magnet; Planed by E.Lawrence as a medical appliance, depending on
||[Germany] Austria annexed.
||[Italy] Jews banned from public office.
||L.Meitner with a help by N.Bohr escapes carrying an
expired passport from Germany to Stockholm via Copenhagen.
||Emilio Gino Segre seeks refuge in U.S.A.
||[France] Radioactivity with a half life of 3.5 hr
produced by neutron irradiation of uranium is from lanthanum, reported
by Curie and Savitch.
||[U.S.A.] Uranium 235 and uranium238(ratio of
1:139 in natural uranium), analyzed by Alfred Nier by means of
Dempster's mass spectrometer.
||[Germany] Isotope-separating device developed by Klaus
Cladius and G.Dicker employing a gas thermal diffusion method.
||[Germany] Uranium nuclear fission: Barium is
detected by Otto Hahn and Fritz Strassmann after irradiation by neutron
of uranium at Kaiser Wilhelm Institute. They asked L.Meitner's comments
by a letter. Beginning of the Barium Fantasy. (Received 1944 Nobel
|1939. 1. 2
||E.Fermi travels to U.S.A. Awarded Nobel prize and seeks
refuge in U.S.A with a help of N. Bohr. Fermi's wife is a Jew.
|1939. 1. 6
||[Denmark] A theoretical explanation of nuclear fission
of uranium written by L.Meitner and Otto Frisch employing a liquid drop
model and theory of relativity. Next day N.Bohr brought a copy of the
paper to U.S.A. Conversion of one fifth of the mass of a proton to
energy is plausible.
||[Denmark] Detection of uranium nuclear fission by a
cloud chamber by Otto Frisch. Later nuclear fission of thorium was
verified. Thorium nuclear fission is triggered with fast neutron.
||[Denmark] Nuclear Fission named by Otto Frisch, an
analogy of bacterial cell division called binary fission, suggested by
William Arnold, an American Biologist.
||[U.S.A.] N.Bohr travels to New York.
Bohr did not wish to make the nuclear fission story public, but John
Feurer announced the news at a meeting at Princeton University.
||[Denmark] Otto Frisch submits a paper of the theory and
experiments on nuclear fission of uranium.
||[U.S.A.] Verification of the uranium nuclear fission by
means of an oscilloscope by Herbert Anderson, a student of Fermi.
Emission of neutron by irradiating hydrogen with deuteron accelerated by
means of cyclotron at Columbia University. Failure in previous
experiment by Fermi in Rome was due to an obstruction by aluminum
||[France] Verification of uranium nuclear fission by J.
and I. Curie. They failed to detect neutron emission.
||[U.S.A.] The fifth Washington meeting sponsored by
American Physics Society. N. Bohr, E. Fermi, Otto Stern, H.C. Urey,
Gregory Bright, Issidor Isaac Rabi, G. Gamow, E. Teller, Merle Tuve.
Lectures by N.Bohrand E.Fermi on the uranium nuclear fission called
||[U.S.A.] Verification of uranium nuclear fission by
Richard Roberts and Robert Meyer. Emission of neutron on irradiating
lithium with deutron accelerated by a van de Graaff accelerator, was
employed for irradiation of uranium. Demonstration to members in the
Washington Conference. Delayed neutron was detected in later
experiments, a discovery suggesting a possibility of reactor control.
||[U.S.A.] Verification of uranium nuclear fission by
Phillip Abelson. Luis Walter Alvarez transferred the news of nuclear
fission of uranium to Abelson. They found tellurium-52 and zirconium-40
as the fission products. J.R.Oppenheimer, as noted by Alvarez,
predicted neutron emission and possibility of developing atomic bomb.
||[U.S.A.] Nuclear fission of 235uranium is
caused by slow neutron, a theory proposed by N.Bohr and John Archibald
||[U.S.A.] The first meeting on nuclear energy for
military purposes. The first proposal by scientists (G.P. Pegram and
E.Fermi) of the development of atomic bomb to Navy. E. Fermi talked on
the controlled reaction by slow neutron, explosion by fast neutron and
reaction in the supernova.
||[France] More than one neutron emitted with nuclear
fission of uranium observed by J. Curie, Hans Halban and Lew Kowarski.
||[U.S.A.] About two neutrons emitted with nuclear
fission of uranium verified independently by L.Szilard and Walter Zinn.
||[France] Number of neutrons emitted with nuclear
fission of 235uranium is 3.5 /fission. Later corrected to
2.6/fission.By F.J.Curie, H.Halban and L.Kowarski.
||[Germany] A secret conference about a research program
on the nuclear bomb in Berlin. A trade embargo on uranium and radium.
Letter of Paul Harteck.
||[U.S.A.] John Dunning's request to Alfred Nier to
||N. Bohr returns to Copenhagen in order to support
||[U.S.A.] Idea of nuclear reactor (pile) by E.Fermi and
L.Szilard.Natural uranium as fuel and graphite as moderator of neutron
|1939. 8. 2
||[U.S.A.] A letter of A.Einstein to President
Roosevelt.L. Szilard, E. Teller and E. Wigner persuaded Einstein to
warn President Roosevelt of German menace. The letter suggested the
possibility of uranium bomb.
||Otto Frisch seeks refuge in England.
|1939. 9. 1
||World War II begins with the German
invasion of Poland. Blitzkrieg by tanks.
|1939. 9. 3
||England and France go to war against Germany.
||[Germany] A secret conference in Berlin on Bohr's paper
about nuclear fission.
||[Germany] The second Berlin meeting. Start of German
nuclear bomb project: Kurt Diepner, Erich Bagge , W. Heisenberg and
||[U.S.A.] Einstein's letter to President Roosevelt,
presented by Alexander Sachs.
||[U.S.A.] The 1st uranium advisory committee. Financial
aid to development of nuclear reactor rather than to yet uncertain
atomic bomb.[A. Lyman, J. Briggs, A. Sachs, L. Szilard, E. Teller and E.
||[England] An idea by J. Chadwick for an atomic bomb
utilizing natural uranium based on a paper by R.Peierls, mass needed
for critical state: 30-40 tons.
||[Germany]Report by W.Heisenberg of the possibility of a
uranium bomb to Germany Department of War.
||[U.S.A.] A discovery by Edwin Mattison McMillan of the
existence of the radioactive substance that stays in uranium on nuclear
||[U.S.A.] A theory of energy production in stars by Hans
Albrecht Bethe, the carbon cycle. (Received 1967 Nobel Prize.)
||[England] An idea by O.Frisch and E.Peierls of
highly enriched uranium bomb presented in a 3 page memo describing
the critical mass as 600 g. Presented via Mark Oliphant of Birmingham
University to Henry T. Tizard.
||[U.S.A.] Separation of uranium235 by A.Nier.
1/1,000,000,000gon a nickel film was sent to John R.Dunning in a letter.
Uranium chloride(IV)or uranium fluoride(IV) was used. Minnesota
||[U.S.A.] Uranium research budget of $6000 authorized:
the purchase cost of graphite for E.Fermi and L.Szilard.
||[U.S.A.] Verification of uranium235
fission with slow neutron by J.Dunning (irradiation by a cyclotron
of a sample separated by A.Nier. (Colombia University)
||[Germany] Invasion and occupation of Denmark.
||[England] George Paget Thomson committee. Small scale
separation experiments utilizing uranium fluoride(VI) agreed.
||[England] The 2nd George Paget Thomson committee.
||[U.S.A.] The 2nd uranium advisory committee. Necessity
of basic research admitted. George B. Pegram and E. Fermi sit in.
||[U.S.A.] President Roosevelt's appeal for cooperation
of The American Scientists Federation. E. Teller decides to participate
in nuclear weapon research.
||[U.S.A.] A new 93rd element is discovered through
irradiation of uranium oxide using deutrons accelerated by a cyclotron.
Called Neptuniumby E.McMillan. (Received 1951 Nobel Prize)
||[U.S.A.] The possibility of nuclear fission of
transuranic elements proposed by Louis A. Turner.
||[France] H. Halban and L. Kowarski escape to England
carrying180 L heavy water with all the data of J.Curie. An test of a
chain reaction utilizing the heavy water carried out at the Cavendish
||[France] Paris falls to the German army.
||[U.S.A.] National Defense Research Committee(NDRC)
swallows up uranium advisory committee. Project for enriching 235uranium
and elimination of refugee scientists discussed.
||[England] A gas dispersion method experiment by Franz
Simon, utilizing a copper partition for separating vapor and carbon
||[England] Renaming of George Paget Thomson committee to
||[Soviet Union] Uranium Committee established in Academy
of Science by Igor Kurchatov. Interrupted due to German invasion in
||[Japan] Army commander Suzuki's report of the
possibility of developing an atomic bomb based on a survey of uranium
deposit in Chinese and Burma.
||[U.S.A.] E. McMillan moves to radar research at MIT.
||[U.S.A.] Start of experiment on gas dispersion method
for enriching uranium-235 by H.Urey and J.Dunning. Uranium fluoride(VI)
vaporizes at 56 deg C.
||[U.S.A.] Nuclear fission of the new element 94239foreseen
by E.Fermi and E. Segre. The possibility of a new element produced in a
||[U.S.A.] A new element 94239. A plan for
production utilizing the 60-inchs cyclotron proposed by E. Lawrence, E.
Segre, E.Fermi and G. Pegram.
||[England] A new idea of heavy water nuclear reactor by
H.Halban. A method for separation of element 93, discovered by Pletcher
was conveyed to U.S.A.
||[England] A plan for a factory for separation of uranium235by
F.Simon. (MAUD committee, gas dispersion method.)
||[England] A possibility of nuclear fission of new
element94 reported to MAUD committee.
||[Japan] A measurement of cross-section started by
Yoshio Nishina. Blueprint of 60-inch cyclotron was a gift of E.
||[Soviet Union] Spontaneous fission of uranium
discovered by George Flerov.
||[U.S.A.] P.Abelson moves to Navy Research Institute in
order to develop a small size nuclear reactor for submarine.
||[U.S.A.]A new element 94238discovered by
E.Segreand Glenn T. Seaborg. Uranium oxide was irradiated by deutrons
accelerated with a cyclotron. (Received 1951 Nobel prize.)
||[U.S.A.] New element 94 chemically separated as a
solution by E. Segre, G. Seaborg and Arthur Wall.
||[U.S.A.] New element 94239 by irradiation of
1.2kg uranium oxide with neutrons emitted from beryllium irradiated by
deutron.1 microgram of element was obtained. E. Segre and G. Seaborg.
||[U.S.A.] E. Lawrence proposes promotion of "uranium
plan" based on conviction of the enriching method of uranium-235
||[U.S.A.] Verification of nuclear fission of new element
94239by E.Segre,G.Seaborg and Joseph Kennedy. Irradiation of
new element 94by paraffin-decelerated neutron emitted from beryllium
irradiated by deutron. About 1.5 times of that by uranium irradiation.
||[U.S.A.] Improved measurement of cross section of
uranium235by M.Tuve (the result was transmitted to England).
||[England] Critical mass of uranium235
calculated by R.Peierls.
||[U.S.A.] Lend-Lease Act. President Roosevelt proposed to
help Britain and other countries defend themselves against Germany.
||[Japan] Army approves atomic bomb research.
||[United Kingdom] Klaus Fuchs, a German emigre
theoretical physicist, a student of R. Peierls, started research of
atomic bomb. A stalwart communist and Soviet espionage agent.
||[Germany] Invasion by Hitler into Soviet Union.
|1941. 7. 3
||[U.S.S.R.] Formation of State Defence Committee (GKO)
[Stalin,Molotov,Voroshilov,Malenkov and Beria]
||[U.S.A.] Cross section of new element 94239
assessed by E.Segre and G.Seaborg. Nuclear fission caused by slow
neutron is 1.7times of that in uranium235.
||[Japan] A lecture by Tokutaro Hagiwara of explosive
||[England] George Paget Thomson and MAUD committee
reports convincing evidence of developing uranium235bomb.
||[England] The conclusion of MAUD committee transmitted
||[U.S.A.] A memorandum regarding a nuclear fission of
the94th element by E.Lawrence. (Possibility of plutonium bomb)
||[U.S.A.] The cross section of new element 94239:The
nuclear fission caused by slow neutron is 3.4 times of that of uranium238.
||[England] Encouragement by M.Oliphant to nuclear power
project in U.S.A.
||[U.S.A.] Triggering by atomic bomb of hydrogen bomb
studied by E. Fermi and E. Teller.
||[U.S.A.] Construction of a graphite pile started by E.
Fermiand L. Szilard.
||[U.S.A.] MAUD report brought to President Roosevelt by
Vannevar Bush. Atomic bomb development project started with
transferring the focus from nuclear reactor to atomic bomb.
||Discussion by N. Bohr and W. Heisenberg of a heavy
water type pile in Copenhagen.
||[U.S.A.] The 3rd NSA report of Compton committee.
(Uranium bomb possible within 3-4 years. Fifty to one hundred million
dollars for uranium enriching plant.)
||[U.S.A.] Submission of the 3rd NAS report to President
||[U.S.A.] Separation of uranium235 by
J.Dunning and U.Booth. (A gas dispersion method using uranium
||[U.S.A.] Data of nuclear fission of new element 94239given
to A.Compton by E.Lawrence.
||[U.S.A.] Separation of 100 micrograms uranium235by
||[U.S.A.] Submission of plutonium bomb project by
||A counterattack to Germany corps by Soviet Union in
||[Japan] A surprise attack on Pearl Harbor. (In U.S.A.
date was 12.7)
||[U.S.A.] A plutonium bomb project started by A. Compton
and V. Bush without report to President Roosevelt.
||[U.S.A.] V. Bush required participation of Engineering
Brigade in atomic bomb project.
||[U.S.A.]OSRD creates the S-1 committee, a special
committee created by V.Bush. [Connant, Briggs, Pegram, Compton,
Lawrence, Urey, Samuel Allison, G.Bright, Edward Condon and Henry
||[U.S.A.] Budget for developing atomic bomb of $651,000
(half year portion) authorized.
||[U.S.A.] Calutron built by E.O. Lawrence: A 184-inch
cyclotron to separate U235. By the summer of 1942 most of
the design problems had been solved. The new machine was named Calutron
after the University of California.
||[U.S.A.] Concentration of the atomic power research
(Pile Plan) to the Chicago's Metallurgical Laboratory. [A. Compton, E.
Lawrence,L. Szilard and others]
||[U.S.S.R.] Soviet Atomic Bomb Project started. Led by
Igor Vasilievich Kurchatov（40 years old）.
||[U.S.A.] Naming of new elements by G.Seaborg: Neptunium
for93 and Plutonium for 94. (Named for planets Uranus, Neptune and
||[Soviet Union] Beria, the director of secret police,
reports western situation of the nuclear development to Stalin, based on
||[U.S.A.] The first bombing of Tokyo by several B-25
bombers taking off an aircraft carrier "Hornet" in the Pacific Ocean.
||[U.S.A.] Chemistry Conference at Chicago Metallurgical
Laboratory[G.Seaborg,E.Wigner,J.Wheeler and others] on
plutonium-separation technology including precipitation method.
||[U.S.A.] An experimental facility for ultra-micro
chemical analysis established at Chicago Metallurgical Laboratory.
||[Soviet Union] A letter from G. Flerov to Stalin
estimating western development of nuclear fission technology from the
fact that papers relating to nuclear fission were gone from scientific
||[U.S.A.] J. Conant's report of the atomic bomb
development research presented to V. Bush, director of the Carnegie
Institution of Washington.
||[U.S.A.] Delayed neutrons are below 1% of prompt
neutrons. K (criticality factor) of prompt neutron is 1 or less and K
including delay neutron is 1 or more.
||[U.S.A.] G. Bright resigned the person in charge of
nuclear fission study using fast neutron claiming insufficient secrecy.
He required a new research institute.
||[U.S.A.] Magnets for cyclotron of 184 inches that
develops Calutron completed. Gross weight was 4000 t.
||[U.S.A.] The designing of Chicago Pile number 1 (CP-1)
||Japanese corps defeated at Midway naval battle.
||[U.S.A.] R. Oppenheimer named as successor of G.Bright:
Arrived at Chicago to research nuclear fission caused by fast neutrons.
||[U.S.A.] 'Nuclear fission bomb' report to the president
submitted by V. Bush and J. Conant. Scientists are convinced of
feasibility of plutonium plan.
||[U.S.A.] The production of plutonium started. 45-inch
cyclotrons of St. Louis University and Washington University were used.
136 kg uranium nitro-oxide(VI) was irradiated continuously for one
||[U.S.A.] President Franklin Roosevelt authorized the
atomic bomb development plan.
||[U.S.A.] The 1st S-1 committee meets. Participants:
Conant,Briggs, Compton, Lawrence, Urey, Murphrey, Major General Wilhelm
D. Styer,Colonel George C.Marshall, Colonel Kenneth D. Nichols.
Centrifuge separation method and gas dispersion method were unfinished.
Electric power required was estimated as 108,000 KW.
||[U.S.A.] Conference at Chicago's Metallurgical
Laboratory.[Compton, Allison, Fermi, Seaborg, Szilard, Teller, Wigner,
Walter Zinn].Start of feasible nuclear warfare study encouraged by
||[U.S.A.] S-1 committee approves construction of heavy
water factory at Canada Trail. Order given to Consolidated Co.
||[U.S.A.] Plutonium arrives at Chicago from St. Louis.
||[U.S.A.] The Berkley summer study. A. Compton had asked
theoretical physicist J. Robert Oppenheimer of the University of
California-Berkleyto study the feasibility of a nuclear weapon.
Oppenheimer convened a summer study at UC-Berkley. [Oppenheimer, H.Bethe,
E.Teller, John Van Vleck, FelixBloch, Richard Tolman, Emil Konopinski,
Robert Serber, L.Alvarez, J.Lawson,Robert Thornton, Robert Becker]
Feasibility concluded. The chief uncertainties lay in the experimental
values for neutron cross-sections, numbers of neutrons that would be
produced in fission and cause other atoms to fission in a rapid chain
reaction. The scientists suggested that such a reaction could be
initiated by assembling a critical mass--an amount of nuclear explosive
adequate to sustain it--either by firing two subcritical masses of
plutonium or uranium 235 together or by imploding (crushing) a hollow
sphere made of these materials with a blanket of high explosives (Tolman).
Teller saw another possibility: by surrounding a fission bomb with
deuterium and tritium, a much more powerful "superbomb" might be
constructed. This concept was based on studies made by Bethe before the
war of energy production in stars. When the detonation wave from the
fission bomb moved through the mixture of deuterium and tritium nuclei,
they would fuse together to produce much more energy than fission, just
as elements fused in the sun produce light and heat. The summer
conferences, the results of which were later summarized by Serber in
"The Los Alamos Primer" (LA-1),provided the theoretical basis for the
design of the atomic bomb, which was to become the principal task at Los
Alamos during the war, and the idea of the H-bomb, which was to haunt
the Laboratory in the postwar era. Seldom has a physics summer school
been as portentous for the future of mankind. By Robert Seidel.
||[U.S.A.] Manhattan Engineering District (MED) created by
Colonel James C. Marshall.
||[U.S.A.] Plutonium separated as a solid by Burris
Cunningham and Louis B.Werner.
||[U.S.A.] Purchase of the uranium ore advised by S-1
||[U.S.A.] Colonel Leslie R. Groves (46 years old) is
appointed to the commander of MED and the director Manhattan Project.
||[U.S.A.] Uranium ore purchased: 1250 tons stored in
open-air on Staten Island since 1940.
||[U.S.A.] The highest priority of supply given to
Manhattan Project by War Production Board.
||[U.S.A.] L. Groves and J. Marshall visit the Navy
||[U.S.A.] L. Groves promoted to Brigadier General.
||[U.S.A.] Trouble at Chicago: Repellence by L.Szilard,
E.Fermi, J.Wheeler and others to Stone & Webster Co.
||[U.S.A.] Clinton, Tennessee (Site X): 5200 acres site
purchased for factory of separation of Uranium235. Oak Ridge
is the name of residence area. For full-scale production of enriched
uranium and for the pilot-scale production of plutonium.
||Anglo-French atomic power accord.
||[U.S.A.] L. Groves visits Chicago's Metallurgical
||[U.S.A.] L. Groves, V. Bush and J.R. Oppenheimer talk at
||[U.S.A.] Construction of production plant with the
electromagnetic separation method ordered by L. Groves to Stone and
Webster Co. [Electric supply by General Electric; magnets by Allice
Chalners; container by Westinghouse.]
||[U.S.A.] L. Groves generally entrusts the "PlutoniumProject"
to DuPont Corp. (Carpenter, president of DuPont, proposed another
plutonium production factory site than Clinton.)
||[U.S.A.] Construction of uranium-235 production plant
decided by Military Policy Committee. Without construction of small
scale testing pilot plants.
||[U.S.A.] Pilot plant omission approved by MED Review
Committee. Plutonium plan is entrusted to DuPont, not to Stone &
||[U.S.A.] Looking for a suitable site for a new
laboratory to design nuclear weapons: [Groves, Oppenheimer, McMillan and
Major John Dudley.] Los Alamos was recommended by Oppenheimer rather
than Jemes Springs the place Dudley, an officer entrusted with search,
||[U.S.A.] The construction of Chicago Pile number 1
||[U.S.A.] Self-sustaining chain reaction in Chicago
Pile number 1 ( Critical State) [Fermi, Zinn, Anderson] Output 50W,
4.5minutes operation. 350 t pure graphite, 35 t metallic uranium. Eugene
Wignerhanded Fermi a bottle of Bertolli Chianti and passed around paper
cupsto the crew. Arthur Compton called the head of the NDRC, James
Conant, and told him cryptically, " the Italian navigator has just
landed in the New World," the secret phrase agreed to, signaling
success. On12.12 output rose to 200W.
||[U.S.A.] L.Szilard opposed by L.Groves for a security
clearance because he is a foreign citizen. Finally Szilard, because of
his earlier brilliant works, was treated like E. Fermi and E. Wigner.
||[U.S.A.] Feasibility of plutonium plan reported by
A.Comptonto L.Groves. The first atomic bomb was scheduled to be
completed by 1945.Later, it would be possible to produce one per month.
||[U.S.A.] DuPont Corp. takes charge of the plutonium
plan. he reward other than the necessary expense was 1 dollar.
||[U.S.A.] Construction of a plant with gas dispersion
method(K25) entrusted to Kellex Co. by L.Groves. An independent power
supply was also constructed not relying on TVA.
||[U.S.A.] Uranium enrichment by liquid thermal dispersion
method is reported by R.Gunn and P.Abelson. Navy was not told of the
critical state of Chicago Pile.
||[U.S.A.] Pile design at Clinton commenced. Water cooling
was suggested by E.P. Wigner.
||[U.S.A.] L.Groves entrusts the operation of the
production plant with the gas dispersion method to Union Carbide Co.
||[Soviet Union] Development of nuclear weapons is
||[U.S.A.] Plutonium plant site at Hanford(Site W) outside
of Richland ,Wash. Cost: $5,100,000.
||[Soviet Union] German army corps surrenders in
||[U.S.A.]. Construction of uranium235
separation factory (Queen Mary) at Clinton starts.
||[England] Explosion of German heavy water factory in
Norway by Norwegian resistance. German nuclear research was greatly
||[Japan] Navy gives up atomic bomb development. Priority
shifted to the radar research.
||[U.S.A.] J.Robert Oppenheimer (38 years old) arrives at
LosAlamos as the director.
||[U.S.A.] Design specification of Calutron decided
||[U.S.S.R.] Kurchatov made attention to Plutonium. Study
of back numbers of Physical Review. Asking to set Soviet intelligence to
find out British and the American progress.
||[U.S.A.] A American officer named George Racey Jordan in
charge of expediting deliveries through the Gore Field, Air Port for
Lend-Lease to Soviet Union, suspected Soviet's transport of US
confidential contained in many black suitcases. His report to Washington
was ignored. Transport of nuclear materials was later revealed.
||[U.S.A.] XA magnet for Calutron completed: The radius of
gyration: 3-4 feet. Magnetic field: 3410 oersted.
||[U.S.A.] N-A barrier for the gas dispersion method
entrusted by L.Groves to Widell Hershey Co.
||[U.S.A.] Los Alamos starts: [J.R. Oppenheimer, John
Manley,H. Bethe, E. Teller, E. Kopinowsky, Felix Bloch, Stanley Frankel,
Eldred Nelson, Robert Serber, Robert Wilson, Richard Feynmann, John
Williams and many others]. Average age, 26 years old. Finally 3000
people. Edward Condon left soon after opening hating militaristic
||[U.S.A.] Implosion Method for firing A-bomb proposed by
Seth Neddermeyer. Blowing a sphere of uranium-235 or plutonium would
assemble these materials so rapidly that they explode.
||U.S.A.- England talks at the White House on Churchill's
request for information of atomic bomb.
||[U.S.A.] William Parsons, Commander (43 years old)
arrived at Los Alamos. A technology officer dealing with radar, he later
engaged in dropping of Little Boy.
||[Japan] Yoshio Nishina reports the feasibility of A-bomb
to army. Employing thermal diffusion method.
||[U.S.A.] Number of secondary neutrons from fission of
plutonium assessed as 2.9 by Robert Wilson with material obtained by
184-nch cyclotron at Los Alamos.
||[U.S.A.] Starting of test shot of gun-type ignition. [W.Parsons]
||England - U.S.A. talk of about A-bomb at Downing Street
10.[Churchill, Sir John Anderson, Lord Cherwell, Henry H.Stimson, V.
Bush, Harvey H. Bandy]. Bush promised Churchill to convey his concern
for Soviet Union's threat.
||Indiscriminate bombing of Hamburg: the first carpet
bombings with 7.28 bombs per second. A huge fire storm developed.
||[Italy] Mussolini is arrested and executed.
||Quebec Conference. [Winston Churchill, Franklin
Roosevelt].Without mentioning about an international agreement regarding
to atomic bomb development or Anglo-French atomic power accord.
||[Germany] Disarmament of Denmark corps.
||[U.S.A.] John von Neumann arrives at Los Alamos to
support S.Neddermeyer's implosion group with a mathematics division.
||Niels Bohr escapes to Sweden by a motor boat. Protection
of Denmark- residing Jews was appealed to Swedish government.
||[England] N. Bohr seeks refuge in England on the flight
of a Mosquito bomber. Due to altitude anoxia he fainted. His son Aage
Bohr arrived at London after one week . R. Tolmann, as a visitor to
England, transmits an invitation by L. Groves to the Manhattan Project.
||[U.S.A.]. Calutron constructed. Due to shortage of
copper for coil of electromagnet, silver owned by Department of Treasury
was used. To the request of 5 - 10 tons, Department of Treasury replied
that they weigh silver by troy ounce. 395,000,000 Troy ounce, worth
$300,000,000dollars. A race-truck on the 2nd floor; vacuum pump room on
the 1st floor; operation personnel 4800 people.
||[U.S.A.] Start of construction of Hanford pile (100-B)
for production of plutonium.
||[U.S.A.] Critical state produced by the implosion
method.[J.V. Neumann, E. Teller] Critical state produced by compression
of explosive substance less than critical mass because of less escape of
||[U.S.A.] The critical state of Clinton Pile (Oak Ridge,
X-10):800 KW; air cooling with blower; A graphite atomic pile; 7.5KW:
1944 Feb.,1800KW 1944. June, 3800ＫＷ: Owed greatly to G.Seaborg.
||[England] Bombing of German heavy water factory in
Norway by B-17 bombers. Heavy water factory exploded previously was
repaired April. Germany decided to move the factory to Germany.
||[U.S.A.] Start of separating plutonium at Clinton,
processing with a remote control plant of 5 tons of uranium bombarded by
||[U.S.A.] Start of remodeling B-29 bomber for A-bomb.
[Norman Ramsey. External size of bomb decided. Thin Man (for Roosevelt)
and Fat Man (for Churchill)]. (N.F.Ramsey received Nobel Prize in 1989.)
||British Mission: English scientists join Manhattan
Project(Quebec accord) [Wallace Ackers, Otto Frisch, R. Peierls, William
J. Penny,George Placzek, P.B. Moon, James L. Tuck, Egon Bretcher, Klaus
Fuchs, James Chadwick, Geoffrey Taylor, Niels and Aage Bohr]
||[U.S.A.] U. S. Army Special Corps (ALSOS) landed in
Italy: [Commander Boris T. Pash] Confirmation of improbable German
development of A-bomb. This was not passed on to the Manhattan Project
||[U. S. A.] Impossibility of production of N-A barrier
for gaseous diffusion method found in study by F. Simon and R. Peierls.
||[U. S. A.] Possibility of pile as a weapon considered by
R. Oppenheimer, N. Bohr and others.
||British Mission: English scientists join Manhattan
Project(Quebec accord) [Wallace Ackers, Otto Frisch, R. Peierls, William
J. Penny,George Placzek, P.B. Moon, James L. Tuck, Egon Bretcher, Klaus
Fuchs, James Chadwick, Geoffrey Taylor, Niels and Aage Bohr.]
||[U. S. A.] Nuclear fission of uranium235caused
by neutrons in cosmic rays discovered by E.Segre. Possibility of slowing
down of core reaction speed implied. Change to Little Boy from Thin Man.
The full length from 17 feet to 6 feet.
||[U. S. A.] A new type barrier for gaseous diffusion
method(J barrier) employed.
||[U. S. A.] George B. Kistiakowsky arrives at Los Alamos
for the chemical explosive division supporting Neddermeyer's implosion
||[U. S. A.] Start of navy liquid thermal diffusion plant
construction:300 columns. [P.Abelson]
||[U. S. A.] Separation of plutonium at Clinton plant
finished. A pilot test. 190 mg.
||[England] Sink of German heavy water, blasting of boat
transporting from Norway to Germany. End of German development of
||[U.S.A.] Klaus Fuchs met with Harry Gold, a Soviet
||[Japan] A report by Yoshio Nishina indicating difficulty
of production of uranium fluoride. The method considered was that had
been given up by P. Abelson.
||[U. S. A.] The first plutonium 239 from
Clinton arrives at Los Alamos.
||[U. S. A.] Start of test dropping of atomic bombs by
B-29.Dropping of mock bomb of Thin Man bomb failed due to hitting
against bomb-bay door.
||Belgium government sells the pre-emption of all the
uranium resource in Congo to U.S.A. and England. [Sir John Anderson,
Ambassador John G. Winant] for $375,000,000 dollars.
||[U.S.A.] Fuchs leaked data (including draft of his own
paper) of gaseous diffusion to Soviet agent.
||[U. S. A.] The first transportation of enriched uranium
235from Clinton to Los Alamos. 10% enrichment.
||[U. S. A.] Kenneth T. Bainbridge is assigned to the
responsible person of the first A-bomb test, Trinity. Trinity named by
||[U. S. A.] Peppermint operation: Portable Geiger
counters, X-ray films and so on for inspecting radioactivity were
prepared for Normandy invasion by Allied forces.
||[U. S. A.] Prediction of fireball associating with
A-bomb explosion by H.Bethe and Robert Christy. Emergence of a fireball
and impulse wave of air heated by soft X-rays given out in chain raction.
||[U. S. A.] Liquid thermal diffusion method for enriching
uranium235 is recommended by J.Oppenheimer to L.Groves.
||[U. S. A.] Explosive Lens for ignition of A-bomb: An
idea developed by James L. Tuck. Production of spherical impulse wave by
combinatorial ignition of explosives with various burning velocity.
||[U. S. A.] IBM computer arrival at Los Alamos. [J.
Neumann, Stanislaw Ulam] For the hydrodynamics of implosion, and
interference of impulse waves.
||Churchill - N.Bohr talk: Bohr's suggestion on
international cooperation of A-bomb development, treatment of Soviet
Union. His apocalyptic viewpoint was not understood.
||[U. S. A.] R. Peierls moved to theory division by
||[U. S. A.] Calutron completion: A new plant for uranium235high
enrichment: radius, 2 feet.
||[U. S. A.] Alamogordo Bombing Range chosen for Trinity
by J.Oppenheimer and K.Bainbridge.
||D-day: Normandy invasion by allied forces. D.Eisenhower
commanding.1500 tanks, 12,000 airplanes, 156,000 soldiers, 1200
||[U. S. A.] A liquid thermal diffusion plant at Clinton
||[Germany] V-1 rocket bombs London: 8070 rockets were
launched by 1944.9.4. 29% of them flew to London.
||[U. S. A.] G. Kistiakowsky as director of explosive
section. S.Neddermeyer withdrew as an adviser.
||[U. S. A.] Highly enriched uranium 235 from
Clinton arrived at Los Alamos.
||[U. S. A.] Absence of feasibility of Plutonium bomb,
concluded.[Midsummer Crisis] Too much plutonium240 was
detected in Clinton sample by E.Segre. J.Oppenheimer was persuaded not
to resign by RobertF. Backer.
||[U. S. A.] The highest priority is given to "IMPLOSION"by
J.Oppenheimer. The abandonment of THIN MAN. Implosion at 10 km/sec is
required in Plutonium bomb. Feasibility was considered of an implosive
type uranium bomb in order to obtain multiple bombs.
||[U. S. A.] Tinian Is. occupation: 6 runways for B-29
bombers were made for attacking Japan.
|1944. 8. 5
||[U.S.A.] David Greenglass, a communist, joined Los
Alamos for supporting development of implosion lens.
||[U. S. A.] Time table of A-bomb production presented by
L.Groves. Several bombs may be made until March-June ,1945 if implosion
method is effective. Otherwise, one bomb is produced by August, 1945.
||[U.S.A.] Klaus Fuchs joined Los Alamos. Chadwick
informed Fuchs that his service was requested.
||[U. S. A.] Advance into Paris by U. S. Army. Special
unit(ALSOS) advanced into Paris next to tanks. [B.Pash, Samuel A.
Goutsmit].They questioned F.J. Curie at the Radium Research Institute
and confirmed the absence of German A-bomb development.
||Roosevelt - N.Bohr talk. Suggestion by Bohr on
international cooperation of A-bomb development , treatment of Soviet
Union. His apocalyptic viewpoint was not understood.
||[U. S. A.] Colonel Paul W. Tibbets (29 years old) made
commander of the 509th Composite Group. He was a test pilot of B-29
||[U. S. A.] General Curtis LeMay made commander of the
20thbomber corp. A strategy of taking off Chinese base for bombing Japan
||[Germany] V-2 rocket bombing of London: 4320 rockets
were launched till March 27, 1945. 1050 of them dropped on England.
||[U. S. A.] Start of charging of metal uranium at Hanford
Pile: 250 t uranium, 100,000 rods of graphite,11m* ×8.5mH)
||Hyde Park Accord reached. [F. D. Roosevelt and W.
Churchill]A secret accord deciding atomic bombing of Japan.
||[U. S. A.] A note of post-war strategy: Sent by V.Bush
andJ.B.Connant to Henry L.Stimson, the secretary of war. Danger of
making A-bomb secret. Participation of Soviet Union to any accord is
||[U. S. A.] Seizure by ALSOS of German uranium ore (68
tons). [B.Pash] 30 tons were found in Toulouse, October ,1944.
||[U. S. A.] The critical state achieved in Hanford Pile.
Operation with 9MW. Rising of cooling water temperature from 10 to 60
deg C. It was due to absorption by xenon135, a fission
product, of neutrons. Cross section of xenon135 of
neutron-absorption is 150 times of cadmium. Critical state in the 2nd
Pile in December 1944. Critical state in the 3rd Pile in 1945.
||[U.S.A.] Robert Christy proposed a bombing core not a
shell of plutonium but a nearly solid subcritical ball (in the form of
two fitted hemispheres). The imploding detonation wave would simply
squeeze the solid mass to criticality.
||[U. S. A.] Start of Calutron operation: 100 g daily
production of 10% enriched uranium.
||[Japan] Kamikaze commando at Layte naval battle.
||[U. S. A.] Start of operation of Navy liquid thermal
diffusion plant at Philadelphia navy arsenal.
||[U.S.S.R.] Production of plutonium(several micrograms)
by Boris Kurchatov [a brother of Igor Kurchatov]
||[U. S. A.] Bombing Japan by B-29 bombers from Northern
Mariana base with a large formation of 100 bombers. The high altitude
bombing failed due to a high speed air current. The discovery of jet
||[U. S. A.] Taking out of irradiated slugs from Hanford
||[U.S.S.R.] Metallic uranium refined.
||[U. S. A.] Start of operation of Calutron: 90 g daily
production of 80% enriched uranium.
||[U. S. A.] Start of implosion experiment with shaped
explosives. Implosive process was examined by X-ray camera taking
hi-speed successive pictures.
||[U. S. A.] Separation of irradiated slugs from Hanford
||[U. S. A.] A balloon bomb from Japan cuts the power
supply to Hanford Pile.
||[U.S.A.] David Greenglass's contact with Julius
Rosenberg, a Soviet intelligence agent, handing a sketch of implosion
lens and a list of asset candidates.
||[U. S. A.] Start of plutonium separation at Hanford.
||[U. S. A.] Start of operation in the gaseous diffusion
plant using a supply of poorly enriched uranium to Calutron. Development
of teflon as a sealant.
||[U. S. A.] Low altitude incendiary bombing of Japan
proposed by C.LeMay, Commander of B-29 bombers corps.
||[U. S. A.] Verification of critical mass of uranium235by
Otto Frisch. Named Dragon experiment by R. Feynman. Accident in February
of neutron irradiation. A victim died.
||[U. S. A.] An ignition device for implosion completed by
Luis W. Alvarez.
||Yalta talk. F. Roosevelt, W. Churchill and Y. Stalin.
Demanded unconditional surrender of Japan: A secret agreement of
attacking of Japan by Soviet Union.
||[U. S. A.] Transport of plutonium239 from
Hanford to Los Alamos as nitric acid solution.
||[U. S. A.] Implosion lens completed by G.
||[U. S. A.] Schedule of Trinity test decided. Implosion
will be employed only in plutonium bomb.
||[U. S. A.] Start of operation in Liquid Thermal
Diffusion plant, supplying poorly enriched uranium to Calutron. After
June, uranium was processed in the order of liquid thermal diffusion
plant, gaseous diffusion plant and Calutron. Improvement of enrichment
with gaseous diffusion plant.
||[U. S. A.] Tinian recommended as the Dispatch base for
A-bomb B-29 by commander Frederick L. Ashworth.
||[U.S.A.] Klaus Fuchs handed Soviet intelligence agent
data of implosion system. He refused to receive 1500 dollars reward.
||[U.S.A.] Leaders of Manhattan Project including Groves,
Office of Scientific Research and Development section head and Harvard
President James Bryant Conant, Hans Bethe, George Kitiakowsky and
Richard Tolman met in Oppenheimer's office and decided tentatively to
develop the lensed, solid-core Christy implosion design as a combat
||[U. S. A.] 100,000 victims killed in large air attack on
Tokyo: 234 B-29 bombers with 1665 tons of incendiary bombs.
||[U.S.A. Germany] US air force attacked Metal-refining
plant in Oranienburg (15 miles north of Berlin) to prevent German
production of metallic uranium.
||[Germany] Start of experimental operation of B-8 nuclear
reactor by W. Heisenberg, K. Diebner, Carl F. von Weizsaocker, Hans
Bethe and others. A cylinder type reactor employing graphite as neutron
reflector and heavy water as modulator. Did not achieve the critical
||[U. S. A.] Verification of critical mass of Plutonium
239 by O.Frisch in Dragon Experiment.
||[Japan] Riken Scientific Institute destroyed: End of
Japanese A-bomb project.
||[U. S. A.] Sudden death of President Roosevelt. Replaced
by Harry S. Truman, the vice president. H. Stimson first explained
Manhattan Project to President Truman in the evening.
||[Germany] German uranium ore found by commander John
Lansdale, Jr. of US army special unit (ALSOS). At a shed in Stuttgart.
Supplied to Manhattan Project
||[Germany] Reactor at Heigerloch seized by U.S. army (ALSOS).
Commanders B. Pash and Samuel A. Goudsmit. Goutsmit is Heisenberg's
friend. Goutsmit's parents had been killed by Nazi in a gas chamber.
||[Germany] German atomic scientists arrested in Hebingen.
[C. Weizsaecker, O. Hahn, Max von Laue]
||[U. S. A.] Truman and Stimson discuss details of
||[Germany] Metal uranium and heavy water found by ALSOS.
||[U. S. A.] The 1st Target Committee meets. [L.Groves,
Thomas F.Farrell,J.Neumann and William G.Penny] Japan, July or August.
Visual flying by a B-29 bomber with the range of 2500km or less.
||[Germany] Death of Adolf Hitler.
|1945. 5. 2
||[Germany] Berlin occupied.
||[U. S. A.] W. Heisenberg arrested by U. S. army ALSOS in
||[Germany] Germany surrenders to allied forces.
||[U. S. A.] Interim committee on nuclear power meets:
Henry Stimson, Ralph Bard, Vannevar Bush, James Byrnes, William Clayton,
Karl Compton, George Harrison: By invitation: Harvey Bundy. Predicts
development of nuclear weapons by Soviet Union in 7 years.
||[U. S. A.] The second Target Committee meets in Los
Alamos: L. Groves, General Farrel, Colonel Seeman, Captain Parsons,
C. Lauritsen, Major Derry, Drs Ramsey, Dennison, Stearns, Tolman,
Oppenheimer, von Neumann, Wilson, Penny, Bethe, Robert. The first
choices of targets for nuclear weapons are: a. Kyoto, b. Hiroshima, c.
Yokohama, d. Kokura Arsenal.
||[U. S. A.] Operation of Kyushu invasion decided by
Douglas MacArthur (army), Chester Nimitz (navy) and Henry H. Arnold
(army air corps). Named " Operation Olympiad," scheduled for November 1.
||[U. S. A.] Joseph C. Grew, undersecretary of the State
Department, of predicts Japanese surrender to President Truman.
||[U. S. A.] L. Szilard expresses his opinion against use
of A-bomb to Presidential advisor J. Byrnes. Rejected.
||[U. S. A.] The third Target Committee meets. Given
report of test bombing carried out in Cuba by Colonel P. Tibbets.
||[U. S. A.] Stimson tells L. Groves to exclude Kyoto from
list of A-bomb targets.
||[U. S. A.] Recommendation on the immediate use of
nuclear weapons given by the Interim Committee: Byrnes, Stimson, G. C.
Marshall, Groves, Harvey H. Bundy, J. Conant, Compton, Lawrence, Fermi,
Oppenheimer. Inviting Soviet Union to Trinity proposed by Oppenheimer.
Decided not to notify Japan before dropping A-bomb. Objections by
||[U.S.S.R] German 130 tons uranium oxide found in a
tannery in Berlin right on the border of American-occupied territory was
seized by Soviet army and shipped to Soviet Union.
||[U. S. A.] Joseph Rotblat resigns of from Los Alamos
because of Germany's surrender. Later he founded Pugwash Conference.
||[Soviet Union] German uranium seized: over 100 tons in
||[U.S.A.] Confidential data including information of
Trinity, atomic bomb, explosive materials handed by Klaus Fuchs to a
||[U.S.A.] David Greenglass handed to the same agent
contacting with Klaus Fuchs the sketch of implosion lens and names of
asset candidates. Received 500 dollars reward.
||[U. S. A.] Recommendation of A-bomb use by Interim
Committee conveyed to President Truman by Stimson.
||[U. S. A.] The 509th Composite Group arrives at Tinian
with 11 B-29 bombers.
||[U. S. A.] James Frank committee recommends notification
before use of A-bomb: J. Frank, Leo Szilard, Eugene Rabinowitch. Seven
scientists in Chicago recommended a show of force demonstration.
||[U. S. A.] Estimation of 63000 war dead or wounded in
Operation Olympiad (Kyusyu invasion) by General G.C.Marshall.
||[U. S. A.] Assembly of the plutonium bomb for Trinity.
||[U.S.S.R.] Confidential data obtained by espionage
agents from USA were shown to Igor Kurchatov.）
||[U. S. A.] Casting of a warhead for uranium235
||[U. S. A.] Plutonium core arrives at Alamogordo.
||[U. S. A.] Explosive assembly arrival at Alamogordo.
||[U. S. A.] A preparatory implosive experiment for
Trinity failed. The defect explosive was replaced by hand work.
||[U. S. A.] Gadget for Trinity completed by Norris E.
Bradberry and others. Installed at top of 30m high tower.
||[U. S. A.] Preparatory implosion experiment declared
indecisive by H. Bethe.
||[U. S. A.] TRINITY test. After 90 minute delay
for bad weather, at 5:29:45. Explosive force of 18.6 kilotons of TNT.
||[U. S. A.] Shipping of Little Boy by cruiser
Indianapolis, 4 hours after Trinity.
||[U. S. A.] Petition to President Truman against the use
of nuclear weapons by L. Szilard and 70 scientists.
||[U. S. A.] Allied Commander D. Eisenhauer advises
President Truman not to use A-bomb; it is unnecessary.
||[U. S. A.] Report from L. Groves of successful Trinity
conveyed to President Truman staying in Potsdam: Later W. Churchill told
H. Stimson that Truman's reaction was clearly observable.
||[U. S. A.] Telegraph by George L.Harrison to Potsdam
informing that dropping A-bomb on Japan is possible after August 1.
||[U. S. A.] Completion of the 2nd plutonium core.
||[U. S. A.] H. Truman told Y. Stalin about A-bomb
experiment. Stalin was already informed by spy of Trinity but never
||[U. S. A.] Approval by President Truman staying at
Potsdam of the order to bomb Japan with A-bomb. The order was written by
||[U. S. A.] Cruiser Indianapolis arrives at Tinian.
Little Boy is unloaded.
||[U. S. A.] Shipping of uranium-235 warhead to Tinian: by
C-54 transport plane.
||[U. S. A.] Shipping of plutonium core and the initiator
to Tinian by C-54 transport plane.
||Potsdam Declaration announced, demanding unconditional
surrender of Japan.
||[U. S. A.] Cruiser Indianapolis sunk by a torpedo attack
from a Japanese submarine, only 4 days after unloading of A-bomb.
||[U. S. A.] Assembling Little Boy, waiting recovery of
||[U. S. A.] Parts of Fat Man arrive at Tinian.
||[U. S. A.] Briefing to crew of B-29 bombers of the 509th
corps. Presentation by William Parsons of documentary film of Trinity.
||[U. S. A.] Bombing date of August 6 decided by Curtis
LeMay. Installation of Little Boy in a B-29 bomber named Enola Gay,
after Captain Tibbets' mother.
||[U. S. A.] Bombing Hiroshima with Little Boy by
Paul W. Tibbets, Robert Lewis, Thomas Ferebee, William S. Parsons,
Morris Jeppson, and others, at 08:16: 45. Explosion equivalent to 12.5
kilotons of TNT from 60 kg uranium235. Bomb's gross weigh was
4 tons. 140,000 civilian citizens were killed. Hibakusya (survivors)
more than 300,000.Physical ailnesses due to radiation exposure, short
term and long term effects.
|1945. 8. 7
||[U.S.S.R.] Lavrenti Pavlovich Beria was appointed to the
head of Soviet atomic bomb project by Stalin.
||[U. S. A.] Statement by President Truman of A-bomb
attack from Cruiser Augusta in Atlantic Ocean on the way back from
||[Soviet Union] Declaration of war against Japan, just
after the German surrender, as promised in Yalta talk.
||[U. S. A.] Fat Man assembled and installed in a B-29
||[Soviet Union] Attacks Japan by invasion of Manchuria.
||[U. S. A.] Bombing Nagasaki with Fat Man by
Charles W.Sweeney, Frederick L.Ashworth, and others. Target changed from
Kokura to Nagasaki because of poor visibility. 20 seconds visibility
over Nagasaki. Time 11:02:00. Explosion equivalent to 22 kilotons of
TNT, using 8 kg plutonium 239. Bomb's gross weight 4.5 tons.
70,000 civilian citizens were killed.
||[Japan] Decision accepting Potsdam Declaration at
midnight meeting of ministers before Tennou Hirohito.
||[Japan] Sending word of acceptance of Potsdam
Declaration through Switzerland, requesting Tennou's position to be
kept. J. Byrnes wished to reject it, nevertheless, H. Truman accepted.
||[U. S. A.] Interruption of transport to Tinian of the
2nd Plutonium core and initiator by the order of G.C. Marshall. The next
plutonium bomb could possibly have been dropped on August 17 or 18.
||[Japan] Response of U.S.A. to Japanese request.
||[Japan] Unconditional Surrender by Japan. The end of the
World War II.
||[U.S.S.R.] Special Commitee on the Atomic Bomb formed. [Georgi
Malenkov, Boris Vannikov, Avrami Zavenyagin, Mikhail Peruvuhin, Peter
Kapitza and Igor Kurchatov]
||[Canada] Igor Gouzenko, a Soviet espionage, escaped from
Soviet Embassy carrying 109 reports, resulting in arrest of 22 Soviet
||[U. S. A.] Manufacturing A-bomb reported: Presented to
L.Groves by major Lauris Norstad. An estimation that 204 atomic bombs
are required if a hypothetical enemy is Soviet Union. The start of cold
||[U. S. A.] Scientific Panel of the Interim Committee
recommends against H-bomb development. [Compton, Lawrence, Germi,
||[U. S. A.] Resignation of R. Oppenheimer from Los
Alamos. Replaced by Norris E. Bradbury.
||[U. S. A.] " A Message to Los Alamos" speech by
Oppenheimer, his resignation lecture foreseeing the atomic age.
||Truman-Attlee-King declaration, the New Quebec
agreement. A doctrine that initiative relating with the knowledge of
atomic energy is kept by U.S.A., G.B. and Canada. Atomic Energy
Commission in United Nations proposed.
||[Czechoslovakia] Soviet Union concluded a secret
agreement with Czechoslovakia granting it exclusive rights to all
uranium mined within country. Jachymov ores is that from which Marie
Curie first extracted polonium and radium.
||[Japan] Cyclotrons destroyed by U.S. Army: 2 in Tokyo, 3
in Osaka and Kyoto.
||[England] Repatriation of German scientists to West
Germany by U.S.A.
||[Soviet Union] Start of developing A-bomb officially
notified to U.S. ambassador
||[U.S.A.] ENIAC (A computer with 18,800 vacuum tubes, 140
kw, 30 tons) ran a first rough version of the thermonuclear
calculations. Los Alamos prepared a half million punched cards of data.
||[U.S.S.R.] Atomic bomb project decided (imitating US-model).[Stalin,
Beria, Morotov, Kurchatov]
||[U.S.A. United Kingdom] Winston Churchill's speech of
Iron Curtain at a small Protestant men's college in Fulton, Missouri.
Nothing less than a call to an all-out atomic race.
||[U. S. A.] International Control of nuclear power
proposed: Dean Gooderham Acheson. Report by R. Oppenheimer.
|1946. 4. 2
||[U.S.S.R.] Atomic bomb laboratory site at Sarov, 400 km
east to Moskow. Soviet Los Alamos.
||[U. S. A.] First conference on development of "Super"
(h-bomb). Meeting of E. Teller, E. Konopinsky, J. Manley, P. Morrison,
von Neumann, S. Ulam, N. Bradberry and K. Fuchs at Los Alamos. Robert
Serber opposed the development. Propose a mixture of deuterium and
tritium in a cylindrical container ignited by the fireball of atomic
||[U. S. A.] Nuclear Control Plan by Bernard M. Baruch
presented in United Nations: International control of nuclear power. It
was counterattacked by a plan by Soviet Union of prohibition of
manufacturing atomic bombs.
||[U. S. A.] Stockpile of nuclear weapons: 9 Fat Man
bombs. Rate-limiting step is plutonium production.
||[U.S.A.] The Crossroads Series tests. The purpose of the
tests was to examine the effects of nuclear explosions on naval vessels,
planes, and animals. A fleet of surplus and captured ships anchored in
the Bikini Atoll lagoon in the Marshall Islands were used as targets.
The weapons used were Mk 3A ("Model 1561") Fatman-type atomic bombs,
essentially unmodified from the wartime designs. Test ABLE at 22:00 30
June 1946, height of burst 160 m. Dropped by B-29 "Dave's Dream", Fell
980 ft short and 1870 ft left of target. Test BAKER at 21:35 24 July
1946, Mk 3A fission bomb (23 Kt) sub-surface test, depth of burst 27.5
m. Wall of intensely radioactive spray contaminates target fleet.
||[Soviet Union] Start of operation of a nuclear reactor
(F-1): 100w, using 400 tons of graphite and 50 tons of uranium seized in
||[U.S.A.] Edward Teller invented a spherical, layered
design of nuclear thermal weapon, called "Alarm Clock" (it might wake up
new generation of nuclear explosives).
||[U.S.S.R.] "Utilization of the nuclear energy of the
light elements" by I.I.Gurevich, Y.Zeldovich, I.Pomeeranchuk, Y.Khariton.