1925 Physician, Martland, describes pathology of bone changes and anemia in radium dial painters.
1925 William Bailey introduces Radithor, a quack radium potion to cure sexual dysfunction and everything else.
1925 International Congress of Radiology organized; establishes International Commission on Radiological Units.
1925 Rhenium discovered by Walter Noddak, Ida Takke, and Otto Berg (Germany).
1925 Neodymium discovered by C. Aver von Welsbach (Austria).
1925-1929 The saga of radium dial painters and iatrogenic cases unfolds.
1926 (July) "Radium Treatment of Carcinoma of the Lower Lip" is published in Radiology, Vo. VII, No. 1.
1926 (Aug) "Radiation of Cancer of the Cheek" is published in Radiology, Vol. VII, No. 2.
1926 (Oct) "Treatment of Lingual Cancer by Radiation" is published in Radiology, Vol. VII, No. 4.
1926 (Oct) "The Treatment of Bladder Tumors with Metal Seeds Containing Radium Emanation" by Dr. Edward L. Keyes is published in The Journal of Medical Society of New Jersey.
1926 (Nov) "Radium Therapy in Rhinology" is published in Radiology, Vol. VII, No. 5.
1926 (Dec) "Radiation of Malignancy of the Maxillary Sinus" is published in Radiology, Vol. VII, No. 6.
1926 (Dec) "Irradiation of Diseased Tonsils" is published in Medical Journal & Record, 124:873.
1926 Erwin Shrodinger publishes the wave theory of matter demonstrating that matter at the atomic level behaves as it consists of waves.
1926 E. Quimby devises film badge dosimeter with energy compensating filters.
1927 (Feb) Werner Heisenberg realizes that it is impossible to establish at any given instant both the momentum and location of a subatomic particle. This is published as his Uncertainty Principle.
1927 (Sept) "Malignancy of the Larynx and Esophagus Treated by Radium Emanation" by Dr. Frank Richard Herriman is published in The Laryngoscope.
1927 Dutch Board of Health recommends tolerance dose equivalent to 15 R/year.
1927 H. Muller shows genetic effects of radiation.
1927 Herman Blumgart, a Boston physician, first uses radioactive tracers to diagnose heart disease.
1928 Organization and first meeting of International Committee on X-ray and Radium Protection (predecessor of ICRP).
1928 Description of basis for Geiger-Mueller counter by Hans Geiger and Walter Mueller at the Physics Institute in Kiel (Germany).
1928 Second International Congress of Radiology establishes International Committee on X-ray and Radium Protection (predecessor of ICRP) and publishes first set of international radiation protection standards; Roentgen unit accepted.
1928 Organization of US Advisory Committee on X-ray and Radium Protection (predecessor of NCRP).
1929 R. d'E. Atkinson and F. G. Houtermans (Germany) theorize that energy from stars is a result of nuclear fusion.
1929 "The energy available through the disintegration of radioactive or any other atoms may perhaps be sufficient to keep the corner peanut and popcorn man going in our large towns for a long time, but that is all." --Dr. Robert A. Millikan (hedging a bit on his statement of 1923).
1929 "Free air" ionization chambers used as primary standards.
1929 Nuclear track photographic plates developed.
1929 Osteogenic sarcoma (bone cancer) is proven in the dial-painter population.
1929-1930 Fifty percent of miners dying at Joachimsthal have carcinoma of lung.
1929-1933 Collaborative work by Schlundt, Failla, et al, on radium metabolism in patients at Elgin State Hospital in Illinois.
1930 Bothe and Becker find that after bombarding beryllium with alpha particles a very penetrating, uncharged type of radiation is produced. They assume, wrongly, that it must be an electromagnetic wave. It is later proven by Chadwick to be the neutron.
1930 Invention of the cyclotron by E. O. Lawrence & MS Livingston at Berkeley.
1930s Vacuum-tube electrometers gradually replace mechanical ones.
1930 Early count rate meter invented.
1931 Van de Graaff electrostatic generator constructed.
1931 Linear accelerator is constructed by Sloan & Lawrence at Berkeley.
1931 "Alpha particles are probably the most potent and destructive agent known to science"--Martland
1932 (Feb 17) Chadwick discovers the neutron using Bothe and Becker's experimental set up. He scoops the Joliot-Curies who believed their "beryllium rays" were another form of electromagnetic radiation.
1932 (Mar) Eben Byers, prominent Pennsylvania industrialist and playboy millionaire, dies of the effects of drinking "Radithor." Others follow.
1932 (Aug 2) Carl Anderson using a specially prepared cloud chamber discovers a particle with the same mass and opposite charge as an electron (positron) in cosmic rays. He wins the Nobel Prize for his discovery in 1936.
1932 "There is not the slightest indication that nuclear energy will ever be obtainable. It would mean that the atom would have to be shattered at will." --Dr. Albert Einstein
1932 G. Failla suggests limit of 0.1 R/day to whole body and 5 R/day to fingers; introduces concept of higher permissible dose to limited portions of body.
1932 Roentgen unit is defined as producing one E.S.U. of either sign in 1 cc of air at STP.
1932 Werner Heisenberg proposes that the nucleus is composed only of protons and neutrons.
1933 DuBridge and Brown compensating circuit, vital for gas-filled radiation detectors, is invented.
1933 First effort to reduce radium body burden by manipulation of diet and administration of parathyroid hormone.
1933 (Sept 12) "The energy produced by the atom is a very poor kind of thing. Anyone who expects a source of power from the transformation of these atoms is talking moonshine." --Lord Ernest Rutherford (after splitting the atom for the first time)
1933 (Oct) The 7th Solvay Conference in Brussels, Belgium is devoted to nuclear physics for the first time. Attendees include: Marie Curie, Rutherford, Bohr, Lise Meitner, Heisenberg, Pauli, Enrico Fermi, Chadwick, George Gamow, Irene and Frederic Joliot-Curie, Patrick Blackett, Rudolf Peierls, Ernest Lawrence.
1934 (Jan 11) First artificially produced radionuclide (P-30 from aluminum bombarded with Polonium alpha particles) by Irene Curie and J. F. Joliot, Paris.
1934 (Mar 12) Szilard applies for a patent, "Improvements in or Relating to the Transmutation of Chemical Elements," stating "In accordance with the present invention radio-active bodies are generated by bombarding suitable elements with neutrons... Such uncharged nuclei penetrate even substances containing the heavier elements without ionization losses and cause the formation of radio-active substances."
1934 (June 28 & July 4) Szilard amends his patent to add "the liberation of nuclear energy for power production and other purposes through nuclear transmutation." He hypothesizes, "a chain reaction in which particles which carry no positive charge and the mass of which is approximately equal to the proton mass or a multiple thereof (i.e. neutrons) form the links of the chain." He describes the concept of critical mass and of reflecting neutrons back into the mass. Further, "if the thickness is larger than the critical value... I can produce an explosion."
1934 (July 4) Marie Curie (born Nov 7, 1867) dies in Sancellemoz, France. The disease is aplastic pernicious anemia of rapid, feverish development.
1934 Fermi mistaken reports new element after bombarding uranium with neutrons. Ida Noddack suggests Fermi split the atom; this is ignored.
1934 Evans at MIT starts whole body counting.
1934 Production and use of radiosodium.
1934 "Tolerance Dose" of 0.1 R/day, measured in air, recommended by Advisory Committee on X-ray and Radium Protection.
1934 "Tolerance Dose" of 0.2 R/day, measured at the surface of the body, recommended by the International Committee on X-ray and Radium Protection.
1934 Enrico Fermi works out theory for beta minus decay.
1934 H. Urey discovers deuterium.
1934-1939 Measurements begin on radium content of natural waters.
1935 G. von Hevesy performs first radioisotope tracer studies using P-32 to measure water turnover rates in goldfish.
1935 Hans Bethe reports new ideas on the prospect of capture by the uranium nucleus of a neutron slowed by collision with hydrogen.
1935 Neils Bohr conceives the "water droplet" model of the nucleus.
1935 Irene and Frederic Joliot-Curie win the Nobel Prize in Physics.
1936 Bragg-Gray principle of charged particle radiation interaction with matter formed.
1936 Victor Hess receives Nobel Prize for cosmic rays.
1936 First use of radioisotopes in therapy by John Lawrence (Berkeley); produced in 37 inch cyclotron; P-32 used on polycythemia vera.
1936 H. Yukawa and S. Sakata (Japan) predict electron capture process to compete with positron emission.
1936-1940 Use of radioiodine from MIT cyclotron. Patients at Mass. Gen. Hosp.
1936-1941 Rat work at MIT on radium but rats more resistant than man to radium effect.
1937 (Oct) Sir Ernest Rutherford (born 1871) dies, his ashes are placed in a corner of Westminster Abbey next to the grave of Isaac Newton.
1937 Lauritsen electroscope used to measure dose.
1937 Extrapolation chamber invented by Failla.
1937 Technetium discovered by Carlo Perrier and Emillo Segre (Italy).
1938 (Dec) Nobel Prize awarded to Enrico Fermi (Italy) for his work on transuranics. The Fermi family (Laura, Enrico's wife, is Jewish) escapes from Italian Nazi persecution to New York.
1938 Electron capture radionuclides discovered by L. W. Alvarez (USA).
1938 Tritium discovery by Alvarez & Cornog; produced in accelerators.
1938 Hahn and Strassman split the atom repeating Fermi's work.
1939 (Jan 6) Hahn and Strassman's experimental results of fissioning uranium published in "Die Naturwissenschaften."
1939 (Jan 13) Frisch offers experimental proof of fission in a Geiger counter.
1939 (Jan 26) Bohr announces uranium releases a few neutrons on splitting. Fermi may have also made the same announcement. He speculates upon the possibility of a chain reaction.
1939 (March 3) Szilard and Zinn prove possibility of chain reaction by performing experiment in Pupin Hall, Columbia University which shows many neutrons are released during fission of uranium.
1939 (March 16) Hitler annexes Czechoslovakia, richest known source of uranium.
1939 (April 29) First official conference on fission is held in Berlin Germany by the Reich Ministry of Education.
1939 (April) The Joliot-Curies publish a report confirming Szilard and Zinn's finding of neutrons released by uranium fission.
1939 (April) Uranverein ("uranium club") founded in Berlin to do work on uranium fission.
1939 (Aug 2) Einstein signs letter, drafted by Leo Szilard and Eugene Wigner, to Roosevelt alerting him to the feasibility of building an atomic bomb and the threat of Germany building one.
1939 (Sept 3) Germany declares war on Great Britain.
1939 (Oct 21) Uranium Committee, appointed by Roosevelt, holds first meeting.
1939 Igor Kurchatov alerts the USSR government of the military significance of nuclear fission.
1939 Correct description of phenomena of nuclear fission by Meitner and Frisch (Germany).
1939 Enrico Fermi patents first reactor (conceptual plans).
1939 Binary scaler introduced as auxiliary pulse-counting equipment.
1939 More useful count rate meter developed.
1939 Francium discovered by Marguerite Duray (France).
1940 (Nov 8) First contract is signed with Columbia University to develop bomb material.
1940 Neptunium-239 discovered by E.M. MacMillan and P.H. Abelson (United States) at Berkeley.
1940 George Flerov of the USSR discovers the spontaneous fission of uranium.
1940 Photomultiplier tube is developed by Larson and Salinger which makes scintillation radiation detectors much more useable.
1940 Astatine discovered by D.R. Corson, K.R. MacKenzie, and E. Segre (United States).
1940s Enormous strides in ion chambers, vacuum tube electrometers, improved G-M tubes, pulse counting, discriminators, linear amplifiers, autoradiography, etc., taken under Manhattan Engineering District (MED) auspices.
1940 Radiation pneumonitis is described by Warren & Gates.
1941 (Feb) Pu-238 isolated by G.T. Seaborg, J.W. Kennedy, E.M. MacMillan, and A.C. Wohl (United States) at Berkeley from products of neptunium decay.
1941 (Sept 18) Werner Heisenberg meets with Neils Bohr to try to convince Bohr and the Western Allies that atomic bomb production is unfeasible and should be stopped. Bohr is unconvinced and suspects Heisenberg's, now working for the Nazis, motives.
1941 Max Permissible Body Burden set at 0.1 uCi for radium recommended by Advisory Committee on X-ray and Radium Protection based on radium dial painters.
1941 First standard for radon (10-11 Ci/l), Evans and Goodman National Bureau of Standards report.
1941 Pecher (Berkeley) finds that radiostrontium behaves like calcium and deposits in bone.
WW 2 Animal work at U. of Rochester on rat with radium excretion.
1942 (Jan 24) A. H. Compton, chairman of the Physics Department at University of Chicago, announces his decision to site the first self-sustaining chain reaction at University of Chicago. This is over the objections of Szilard (Columbia U.) and Lawrence (Berkeley).
1942 (June 23) Werner Heisenberg's fourth experimental atomic pile, the L-IV, explodes spewing burning particles of uranium twenty feet in the air and catching the lab on fire. Heisenberg and Robert Doepel are nearly killed.
1942 (Aug 25) Entire world's supply of plutonium spilled and recovered from soggy copy of Chicago Tribune (Met Lab).
1942 (Sept) The Manhattan Project is formed to secretly build the atomic bomb before the Germans.
1942 (Nov 16) Construction begins on Chicago Pile 1 (CP-1) begins.
1942 (Nov) Los Alamos is selected as site for atomic bomb laboratory. Robert Oppenheimer is named director.
1942 (Dec 2) First sustained and controlled chain reaction in an atomic pile at University of Chicago. Reactor is graphite moderated. Fermi oversees design and building. Fission products expected. Arthur Compton sends message to James Conant: "The Italian navigator has arrived at the shores of the new world and found the natives were friendly. It is a smaller world than he believed."
1942 Beginning of biomed work at Chicago's Michael Reese Hospital on uranium (cells & whole organism).
1942-1943 Concern develops at Metallurgical Laboratory (Chicago) about potential hazards of radioxenon & I-131 and fission products.
1942-1945 Concern over possible use of fission products in radiological warfare leads to Projects Peppermint and Gabriel (secret study on fallout effects).
1943 (Apr 1) The security gates begin operating at Oak Ridge, TN.
1943 (Apr) Ground broken for Hanford reactors, built to produce plutonium for Nagasaki bomb.
1943 Clinton reactor goes into operation at Oak Ridge.
1943 Uranium toxicology studies at U. of Rochester.
1943-1947 Polonium injected into incurable patients at Rochester, NY. Potential doses greater than occupational limits.
1944 Substantial group begins work at Met Lab (Chicago) on biomedical aspects of fission products.
1944 Air limits for plutonium-239 derived by H. Parker at Met Lab.
1944 Curium discovered by G.T. Seaborg, R.A. James, A. H. Ghiorso (United States).
1945 (May 14) Plutonium injected IV into human subjects at Los Alamos. Eighteen subjects injected that year.
1945 (June 6) Criticality accident at Los Alamos, 14 people exposed, some up to 3000 rem gamma and neutrons.
1945 (July 16) Trinity Test (Alamagordo, NM) cattle receive beta burns. 19 KT yield. First atomic bomb.
1945 (July) Szilard writes Roosevelt warning of arms race: "The development of atomic power will provide the nations with new means of destruction. The atomic bombs at our disposal represent only the first step in this direction, and there is almost no limit to the destructive power which will become available in the course of their future development. Thus a nation which sets the precedent of using these newly liberated forces of nature for purposes of destruction may have to bear the responsibility of opening the door to an era of devastation on an unimaginable scale."
1945 (Aug) Photographic film at Eastman Kodak fogged from contaminated packing paper (fallout from Trinity).
1945 (Aug 6 & 9) Hiroshima and Nagasaki atomic bombed.
1945 (Aug 21) Harry Daghlian, a Los Alamos lab tech, conducts an unauthorized experiment and is lethally irradiated; first North American to die of acute radiation sickness.
1945 (Sept 5) The ZEEP reactor achieves first self-sustaining fission chain reaction in Canada.
1945 (Sept) USSR occupies Czechoslovakia. Soviet commanders order all German plans, parts, models, and formulas regarding the use of atomic energy, rocket weapons, and radar be turned over to them. USSR infantry and technical troops occupy Jachimov and St. Jaochimstal (the only European source of uranium.)
1945 (Dec 24) An attaché at the US Embassy in Moscow warns that "the USSR is out to get the atomic bomb. This has been officially stated. The meager evidence available indicates that great efforts are being made and that super-priority will be given to the enterprise."
1945 Landmark paper published by Cantril and Parker on tolerance dose.
1945 K. Z. Morgan circulates first comprehensive calculations of maximum permissible body contents and concentrations in air and water for many radionuclides in a Met Lab Report called "Tolerance Concentrations."
1945 Standards developed for plutonium on basis of animal toxicity data. Earliest attempts are on basis of half-life relative to radium, but animal work proves this to be incorrect.
1945-1946 Inhalation experiments at Rochester made basis for revision of standard for uranium. Different levels recommended for soluble versus insoluble salts.
1945-1947 18 patients (one a five year old) injected with plutonium at Rochester, NY, Oak Ridge, TN., U. of Chicago, and UCSF. No informed consent; potential doses much greater than occupational limits.
1945 Promethium discovered by J. A. Marinski, L. E. Glendenin, C.D. Coryell (United States).
1945 Americium discovered by G.T. Seaborg, R.A. James, L. O. Morgan, and A. Ghiorso (United States).
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