Nuclear History archive — page 22

A vintage wooden slide rule and a stick of chalk on a sunlit attic window sill behind a diamond-pattern wire mesh

The Einstein Letter & the Manhattan Project Begins

The 1942 Berkeley Summer Study and the "Super"

In summer 1942 Oppenheimer's "luminaries" at Berkeley concluded a fission bomb was feasible but needed about twice the material once estimated, discussed Teller's fusion Super, and judged atmospheric ignition extremely unlikely.

A 1940s train compartment table with a blank notebook, fountain pen and coffee cup, and a sunlit flat-topped mesa seen through the window

The Einstein Letter & the Manhattan Project Begins

Why Groves Picked Oppenheimer (1942)

In October 1942 Leslie Groves settled on J. Robert Oppenheimer to direct the bomb laboratory despite concerns over his inexperience, politics and lack of a Nobel Prize, and on 16 November the two chose the Los Alamos Ranch School mesa as its site.

A blue engineering blueprint of a five-sided building on a bright drafting table, with a single silver star, a brass compass, a pencil and a small glowing atom diagram in one corner

The Einstein Letter & the Manhattan Project Begins

General Groves Takes Over the Manhattan Project (1942)

Appointed on 17 September 1942 and promoted to brigadier general six days later, Leslie Groves bought 1,250 tons of uranium ore, secured the Tennessee site and the top AAA priority, and brought in DuPont within weeks.

A pale carved wooden relief model of Manhattan island on a white drafting table with a brass pin at its southern tip, beside a folded blueprint and a red ribbon

The Einstein Letter & the Manhattan Project Begins

Why "Manhattan"? Creating the Manhattan Engineer District (1942)

In June 1942 Colonel James C. Marshall was told to form a special Army engineer district for the bomb project; on 13 August it became the Manhattan Engineer District, named after its first headquarters at 270 Broadway, New York.

A half-open honey-coloured oak laboratory door with a frosted-glass pane and an empty brass nameplate in a bright corridor, golden light spilling out, beside a small table holding a black graphite brick and a closed notebook

The Einstein Letter & the Manhattan Project Begins

The Birth of Chicago's Met Lab (1942)

Arthur Compton's January 1942 decision to centralise reactor and plutonium research in Chicago created the Metallurgical Laboratory, which grew from 153 to over 2,000 staff and became Argonne National Laboratory.

Desk-scale models of four uranium separation and reactor devices at the ends of a brass crossroads signpost on a polished wooden table

The Einstein Letter & the Manhattan Project Begins

Code Name S-1 — The Committee Behind the Bomb Research

Renamed S-1 in 1941 to hide the word uranium, the committee reorganized for an all-out effort in December 1941, chose in May 1942 to push all four production routes, and in June 1942 became a six-member executive committee as the Army took over construction.

A small olive-green vintage safe with brass fittings standing slightly open, a ribbon-tied folder glowing inside and a sprig of holly in front, on a bright background

The Einstein Letter & the Manhattan Project Begins

Pearl Harbor and the Bomb Decision (1941)

Roosevelt approved accelerated uranium research on 9 October 1941 and S-1 announced an all-out effort on 6 December; after Pearl Harbor the programme gained wartime urgency and money, and full-scale plants were approved in December 1942.

A slightly open black metal deed box with a brass lock, holding a softly glowing copper magnetron block, against a bright sky and sea

The Einstein Letter & the Manhattan Project Begins

The Tizard Mission (1940)

Between August and November 1940 the Tizard Mission shared the cavity magnetron, jet engine data and early MAUD Committee uranium work with the United States, founding the radar boom and the channel for later nuclear cooperation.

A blank sheet of cream paper on a sunlit walnut desk with brass and glass miniatures of a radar dish, a laboratory flask, a glowing vacuum tube and a proximity fuze linked by thin glowing blue lines, beside a black and gold fountain pen

The Einstein Letter & the Manhattan Project Begins

Vannevar Bush, the NDRC and the OSRD (1940–1941)

In June 1940 Vannevar Bush won Roosevelt's approval for the NDRC, which absorbed the uranium committee, and in June 1941 Executive Order 8807 turned it into the OSRD, home of the S-1 uranium section.

An open vintage wooden cigar box on a white laboratory bench, holding a tiny softly glowing metal disc on white cotton, beside a glass watch-glass dish and a slender glass pipette

The Einstein Letter & the Manhattan Project Begins

Seaborg and the Discovery of Plutonium (1941)

On the night of 23 February 1941 Seaborg's Berkeley team identified element 94; on 28 March a 0.5-microgram sample showed plutonium-239 splits under slow neutrons, about 1.7 times more readily than uranium-235.