Celebrating Building 20: History

Building 20 was completed in December 1943 to house part of the Radiation Laboratory (Rad Lab), the successful collaboration between scientists and the military that focused on improving the radar technology that greatly contributed to the Allies' victory in World War II. The Rad Lab designed approximately 50% of the radar used to shoot down enemy bombers and guide Allies' planes during the war.

The Radiation Laboratory was one division of the National Defense Research Committee (NDRC). In June 1940, President Franklin D. Roosevelt authorized Vannevar Bush to chair the NDRC. In early July 1940 Bush formally established five divisions, Armor and ordnance (Division A); Bombs, fuels, gases, chemical problems (Division B); Communications and transportation (Division C); Detection, controls, instruments (Division D); and Patents and inventions (Division E). Karl T. Compton headed Division D, and the detection section focused investigating existing microwave technologies. At the end of the summer, the Microwave Committee found that they were prevented from developing radar that worked on higher frequencies by the absence of equipment that could generate short wavelengths of about 10 cm. However, in September 1940 a British team arrived in the U.S. with a 10cm cavity magnetron. Soon after this, the Radiation Laboratory was established to concentrate on the following three projects: microwave AI (aircraft interpretation), high-accuracy gunlaying radar, and aircraft navigation. L. A. DuBridge was selected to be the director, and MIT was selected to be the location of the Rad Lab.

When the first 48 Rad Lab employees began working on the high priority radar projects, the lab was located in MIT's Building 4 in room 133. By December 1940, a radome had been constructed on the top of Building 6 and the number of employees was increasing. The lab continued to expand and temporary structures were built. In 1941, Building 24 went up. Building 22 was completed in May 1942. (Operations expanded off-campus too, and the Rad Lab used various field stations and air strips.) In the spring of 1943, once again, the Rad Lab faced the need for more space on the MIT campus.
Building 20 and
Building 22
Building 20, as it looked circa 1946. Building 22 is visible in the upper right corner of the image. Photograph courtesy of the MIT Museum.

The Radiation Laboratory made contact with the Boston architectural firm McCreery & Theriault. On 2 April 1943, George McCreery, one of the principals of the firm, sent a letter outlining three schemes for the new building to the attention of Dr. A. J. Allen, Director of the Rad Lab. In the letter (now in the MIT Institute Archives), McCreery refers to the new structure as the "Building 22 Annex." All of the schemes propose a three- story building similar to Building 22 with concrete footings, an "all wood frame...consisting of wood columns and wood girders," and an exterior covered with grey asbestos shingles. The schemes only differed in the size (and, subsequently, the cost) of the new building; scheme A would contain 192,420 square feet, scheme B, 174,320 square feet, and scheme C, 128,400. The location of the proposed building required the relocation of MIT's squash courts, "Board Track," and "the Flame Thrower."
Site of Building 20, circa 1936
Detail of campus plan, circa 1936, showing the Squash Courts (the rectangular building to the right of the Board Track), and the north end of the Athletic Field, the eventual site of Building 20.

By early May, McCreery & Theriault had refined the scheme for Building 20, and according to two letters dated 1 May 1943, had completed the design for the building, and the PD200, a form required by the federal government. One of the letters clearly outlines the project:

The construction of a three story temporary wood frame building meeting with the requirements of the Radiation Laboratories to be located east of the Radiation Laboratory Building #22, and north of the present M.I.T. Swimming Pool. This structure together with its connecting bridges has a total floor area of 196,200 sq. ft.

The estimated cost of the project totalled $1,044,750. This included the cost of Building 20, $848,513, and the estimate for the related projects, $196,239. (The related projects included the relocation of a few campus athletic facilities and the construction a garage and tower section.) Because of the zoning laws of the City of Cambridge, the architects were required to apply to the Cambridge Board of Appeals for a variance to construct the wooden building. A letter from George McCreery from 1946 described the decision of the board:

We received the decision for the Cambridge Board of Appeal on May 5, 1943 allowing us to construct the building as a war measure, the life of said building to be for the duration of the war and six months thereafter.

Construction was completed quickly and in December 1943, when Building 20 was ready for occupancy, portions of nine different divisions of the Radiation Laboratory moved in. These divisions included Transmitter Components, Receiver Components, Ground and Ship, Beacons, and the Business Office.

Building 22 and 20,
circa 1946

Detail of campus plan, circa 1946 includes Building 20 and Building 22.

The developments in radar technology made at Rad Lab directly aided the Allies efforts during WWII. At the height of the war, the Rad Lab employed 3,897 people. The press release dated 14 August 1945 states that during its five year existence, the Rad Lab "pushed research in this field ahead by at least 25 normal peacetime years."

In August 1945, the Rad Lab began making preparations for closing its doors. Plans were under way to bring projects to a close, settle personnel contracts, and publish the technological progress and research findings of the lab in the Radiation Laboratory Series. Throughout 1946, the spaces the Rad Lab occupied were cleaned out and the radomes on the roofs were dismantled. However, the buildings were not dismantled. MIT realized that the buildings would be helpful as enrollments increased dramatically. The MIT President Report, 1945- 1946, states, "the Institute space occupied by the war projects has been largely recaptured, and the temporary buildings...have been retained by the Institute to aid us in handling the postwar overload of students." Building 22 was converted into a dormitory, and by 1947 it housed approximately 600 students. Building 20 was to remain useful to MIT as the site of machine shops, research labs, and offices.

Even though the end of World War II necessitated the end of the Radiation Laboratory, individuals at MIT, in the military, and in the government, recognized the value of continuing scientific and technological efforts in the fields of electronics and microwave physics. The day after the Radiation Laboratory was officially terminated, 31 December 1945, the Basic Research Division was established, on 1 January 1946. Six months later, the Basic Research Division officially became part of MIT under the newly established Research Laboratory of Electronics (RLE).

A campus plan, dated June 1946, describes Building 20 as a "temporary war research building, now used for peacetime educational and research experiments." Building 20's A wing became the primary campus location of the Research Laboratory of Electronics (RLE). RLE was an interdisciplinary lab initially comprised of five groups: microwave electronics, microwave physics, modern electronic techniques, microwave communication, and electronic aids to computation. Each research group had space in Building 20 and the lab's headquarters were located in 20A-122. Building 20 also became the first home for another interdisciplinary research organization, the Laboratory for Nuclear Science (LNS). Various divisions of LNS were located in Building 20: cosmic ray group (20B-124), cyclotron group (20B- 115), theoretical group (20B-213), and the machine shop (20B- 021). Room 20B-119 was location of the headquarters for LNS, and its purchasing office was found down the hall in 20B-129.

RLE and LNS occupied significant portions of Building 20 until 1957, when Building 26 was completed. Then, the headquarters of both laboratories, and most of their research groups, moved into the Karl T. Compton Labs (Building 26). It is interesting to note that Building 22, a temporary structure (like Building 20), remained standing until the mid-1950s, when it was torn down to make room for Building 26. However, Building 20 continued to be occupied by a variety of departments. As space opened up in the building, it was filled by the expansion of the groups remaining in the building, or, by other labs or offices moving in.

Although RLE and LNS occupied many rooms in Building 20 after the end of World War II, some space in the building was made available to other labs and departments. The Radiation Laboratory was a collaboration between scientists and the military and, after the war, various offices of the armed forces continued to be located in Building 20. For example, the Navy Research Office, the Navy Auditor's Office, and the Navy Development Contractor all were housed in the building. During the 1950s the headquarters for all three ROTC (Reserve Officers Training Corps) programs (Army, Air Force, and Navy) moved into various rooms in E wing.

Building 20 was the site of the development of MIT's well- known linguistics program. Both Morris Halle and Noam Chomsky had offices in the building for over three decades. In 1976, the Philosophy department administratively merged with the Linguistics program to form the Department of Linguistics and Philosophy. Until the summer of 1997, this department was located in Building 20. Other notable longterm occupants of Building 20 include the Tech Model Railroad Club in 20E-214, the UROP offices (Undergraduate Research Opportunities Program), and Occupational Medical Services (this became the Environmental Medical Services). For several lists of Building 20 occupants (during a few specific years), and a nearly complete list of all Building 20 occupants, please see the Building 20: Occupants page.

History researched and written by Nancy Heywood, 4 March 1998, slightly revised 25 March 1998.
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