Nuclear History archive — page 23

A polished vintage brass-and-black telegraph key on a light oak desk beside a blank telegram slip and a curl of blank paper tape, in bright daylight

The Einstein Letter & the Manhattan Project Begins

The MAUD Committee Report (1941)

Named after the line "Maud Ray Kent" in a 1940 telegram, Britain's MAUD Committee reported in July 1941 that a uranium bomb was practicable, and Mark Oliphant carried the case to the United States.

A black 1940s typewriter with a blank sheet of paper and a small glowing glass sphere above it, beside a slide rule on a sunlit desk

The Einstein Letter & the Manhattan Project Begins

The Frisch–Peierls Memorandum (1940)

In March 1940 Otto Frisch and Rudolf Peierls estimated that the critical mass of pure uranium-235 might be about a kilogram, warned of fallout and civilian deaths, and urged Britain to act, leading to the MAUD Committee.

A small stack of black graphite bricks tied with a red ribbon beside a jar of yellow uranium oxide powder and a brass desk bell on an oak desk

The Einstein Letter & the Manhattan Project Begins

The Briggs Uranium Committee (1939–1941)

In October 1939 a three-man committee under Lyman Briggs began the US government's uranium work, recommending 4 tons of graphite and 50 tons of uranium oxide and spending a first $6,000 before the NDRC absorbed it in June 1940.

A brass-and-mahogany model of an early paddle-wheel steamboat served on a silver tray at a sunlit 1930s breakfast table, with toast, a silver coffee pot and a cup of coffee

The Einstein Letter & the Manhattan Project Begins

Alexander Sachs Briefs Roosevelt (1939)

Alexander Sachs read the Einstein letter to Roosevelt on 11 October 1939 and, by his account, persuaded him at breakfast the next day; Roosevelt's reply of 19 October created the Advisory Committee on Uranium.

A plain cream envelope held down by a beach pebble on a sunlit wooden dock, with a small wooden sailing dinghy moored on a calm bay behind it

The Einstein Letter & the Manhattan Project Begins

The Einstein–Szilard Letter (1939)

In summer 1939 Leo Szilard twice visited Einstein's holiday cottage; the resulting letter of 2 August warned Roosevelt of extremely powerful uranium bombs and of German moves on uranium.

An open navy velvet medal case with two round recesses: one holds a gold medal with a laurel wreath, the other is empty and lit by a soft beam of light, with a green sprig beside it

The Discovery of Fission

Hahn's Fission Nobel and the Exclusion of Lise Meitner

Otto Hahn alone won the 1944 Nobel Prize in Chemistry for fission; Lise Meitner, nominated 49 times, was left out for reasons historians later traced to committee structure, wartime isolation and haste.

A wooden coat stand in a sunlit 1930s physics laboratory holding a single jacket that is half white lab coat and half olive military tunic with brass buttons

The Discovery of Fission

World War II Begins: Fission Research in Six Countries (1939–1940)

When war broke out on September 1, 1939, no country yet treated fission as a top-priority weapon, but German Army Ordnance, France's Ministry of Armament, a US uranium committee, a Soviet commission and Japan's RIKEN were all drawing the research toward the state.

A stack of thin translucent cigarette papers on a filter-paper disk dusted with pale yellow uranium oxide, beside a brass orrery holding a pale cyan planet and a deep blue planet

The Discovery of Fission

McMillan and Abelson Discover Neptunium (1940)

In spring 1940 at Berkeley, McMillan and Abelson showed that a 2.3-day activity grew from 23-minute uranium-239 and was element 93, submitting "Radioactive Element 93" on 27 May 1940.

A dented vintage aluminium canister lashed with rope to a wooden pallet on the deck of an old cargo ship at sunrise, with a hazy harbour behind

The Discovery of Fission

Smuggle the 26 Cans: Norway's Heavy Water, 1940

In March 1940 Jacques Allier took Norsk Hydro's 185 kg of heavy water to Paris; in June Halban and Kowarski shipped it from Bordeaux to Britain on the SS Broompark.

A vintage stack of thin metal plates coated in yellow uranium oxide on a wooden table in an empty marble-pillared metro hall, with one tiny spark between the plates

The Discovery of Fission

Splitting on Its Own: Spontaneous Fission, 1940

In 1940 Flerov and Petrzhak, working under Kurchatov, found spontaneous fission of uranium, ruled out cosmic rays in Moscow's Dinamo metro station and reported it in Physical Review 58, 89, while Zeldovich, Khariton and a new uranium commission laid the first Soviet groundwork.