Battles & Wars › World War II › Radar (and Britain's Chain Home)
MIT Radiation Laboratory
October 1940 – December 1945· Arms maker, factory or program· Arms makers & war industry
Well documentedSolid records, physical evidence or scientific consensus.
The MIT laboratory in Cambridge, Massachusetts, that turned Britain's cavity magnetron into about 100 types of working radar.
See it on the Battles & Wars map →What happened
Set up in October 1940 after the Tizard Mission, the Radiation Laboratory was paid for by the government's National Defense Research Committee and run by MIT, with Lee DuBridge as director. Its name was a cover, suggesting nuclear physics. Staff grew to nearly 4,000. It designed about 100 radar systems, including airborne sets for hunting submarines, the SCR-584 that aimed anti-aircraft guns, and the LORAN navigation system. Firms such as Western Electric, Raytheon and General Electric mass-produced them.
Why it matters
It became the model for government-funded university science, a template for the Manhattan Project and Cold War labs; several of its scientists later won Nobel Prizes.
How we know
The lab's own 28-volume Radiation Laboratory Series of technical books (1947–53), MIT archives, and government research records, summarized in Henry Guerlac's history Radar in World War II.
Still debated
The popular line 'the atom bomb ended the war, radar won it' is a slogan, not a measured verdict.
Connections (3)
▸MIT Radiation Laboratory turned into working radars the Cavity magnetron and the Tizard MissionWell documented
The connection
The Tizard Mission's magnetron worked, but turning it into radar sets needed receivers, antennas, displays and factories. The Rad Lab, founded weeks after the mission arrived, had a working microwave radar by early 1941 and went on to design many of the microwave radars the Allies used.
When and how
Cambridge, Massachusetts, from late 1940; physicists such as Lee DuBridge, Luis Alvarez and I. I. Rabi, advised by Britain's Edward 'Taffy' Bowen.
How we know
The Rad Lab's own reports and technical series, and British and US records of the Tizard Mission's handover.
Debates and open questions
How much Britain gained in return, beyond American factory capacity, is debated; some British scientists felt the US later took the credit.
▸MIT Radiation Laboratory designed microwave radars that hunted U-boats in the Battle of the AtlanticWell documented
The connection
Rad Lab designs such as the SCR-517 and ASG airborne radars let US patrol planes find surfaced U-boats at night or in fog. Fitted to escort-carrier aircraft and long-range Liberators, they helped close the mid-Atlantic air gap in 1943. The lab also developed LORAN radio navigation, giving ships and aircraft accurate positions at sea.
When and how
Western and mid-Atlantic, 1942–43; US Navy and Army Air Forces anti-submarine squadrons.
How we know
Rad Lab histories and Navy records link specific radars to U-boat detections and sinkings.
Debates and open questions
British and American radars both claim credit, and with codebreaking and new tactics arriving in the same months, the radar share is hard to isolate.
▸Raytheon (radar magnetrons to the Patriot missile) built radar sets designed by MIT Radiation LaboratoryWell documented
The connection
The MIT Radiation Laboratory, a wartime team of several thousand scientists and staff, designed about half the radars the US used in World War II. It did not mass-produce them. Raytheon, near Boston, was one of the firms that did, building magnetrons and shipboard radar sets such as the SG surface-search radar.
When and how
Cambridge and Waltham, Massachusetts, 1940–45; Rad Lab director Lee DuBridge; Raytheon's Laurence Marshall and Percy Spencer.
How we know
Rad Lab and Navy contract records, the lab's 28-volume technical series, and company histories.
Debates and open questions
Which designs were the Rad Lab's and which were improved by industry engineers is often blurred in the histories of both.