Luis W. Avarez (c. 1940s). The Nobel Laureate made
significant contributions to the Manhattan Project.

National Hispanic Heritage Month (September 15 to October 15, 2015) provided an opportunity to remember Luis W. Alvarez’s involvement in the Manhattan Project. The U.S. Department of Energy Office of Legacy Management (LM) has responsibilities at several sites where Alvarez contributed to the Manhattan Project, including the Site A/Plot M, Illinois, Decommissioned Reactor Site; the Chicago South, Illinois, Site; and the Bayo Canyon, New Mexico, Site.

Alvarez began his Manhattan Project work at his alma mater, the University of Chicago, in the fall of 1943. The university was home to the project’s metallurgical laboratory—referred to as Met Lab—which led research into plutonium-production reactors. Shortly after arriving, Alvarez was told to report to the inconspicuously named Site A in the Argonne Forest, 20 miles south of Chicago. On his first trip out, he was escorted by a bodyguard from the U.S. Army. Over the next 6 months, he made the hour-long commute to Argonne aboard Met Lab’s small, blue school bus that Manhattan Project scientists had nicknamed the Blue Flash.

Before Alvarez’s arrival, the world’s first reactor, named Chicago Pile-1 (CP-1), was constructed at Met Lab on a squash court under a University of Chicago stadium. CP-1 was dismantled in early 1943 and moved to Site A’s remote location. The rebuilt reactor was renamed CP-2. Alvarez described it as “a 30-foot cube of graphite bricks set with slugs of uranium oxide and metal surrounded by a thick concrete shield.”

Site A in the 1940s. Alvarez traveled an hour by bus to reach Site A in the
Argonne Forest outside Chicago.

At the time, CP-2 was used to test the purity of graphite and uranium components before sending them to the newer and larger production reactors at Hanford, Washington, and Oak Ridge, Tennessee. It did not take Alvarez long to learn how to operate CP-2, a task he found tedious despite its significance. He later recalled his work as dull, “but an essential service to the cause.” Still, Met Lab gave him a chance to decompress. Having spent the early war years performing an increasing amount of administrative work at a radar laboratory, he was glad to get back to theoretical physics and hands-on research.

During Alvarez’s time at Met Lab, General Leslie Groves of the U.S. Army Corps of Engineers, tasked him with determining a way to detect if Germany was operating nuclear reactors. Taking up the assignment, Alvarez moved his office from Site A to Eckhart Hall on the University of Chicago campus. To fulfill the General’s request, Alvarez designed instruments that could be flown over enemy territory to collect air samples, which could then be tested for radioactive gas. The equipment did not detect anything when it was eventually put to use. Unknown to the U.S., the German atomic bomb program had largely stalled, so there was nothing to detect.

Chicago Pile-2 (CP-2) in 1943.

In spring 1944, Alvarez left Met Lab to join the work at Los Alamos. Compared to Hispanic Americans in New Mexico, the Alvarez family were relative newcomers to North America. Louis Alverez’s paternal grandfather had arrived in the U.S. from Cuba during the 1870s. In contrast, Spaniards had arrived in what became New Mexico during the sixteenth century. In fact, Hispanic American homesteaders had been among those displaced by the creation of the Los Alamos Laboratory.

Ethnicity reinforced social divisions at Los Alamos. Hispanic Americans from nearby towns, such as Española and Chimayó, took on much of the service work for the new community in contrast to the technical work performed by the predominantly non-Hispanic laboratory staff. In his autobiography, Alvarez recollected that “Chicano” crews had the dirty job of shoveling coal into furnaces. He also encountered prejudice when, for example, the wives of fellow scientists protested after discovering that a family with the Hispanic name “Alvarez” had been assigned to their apartment building. He later observed that “they certainly did not count Spanish-Americans among their best friends.”

Nevertheless, Alvarez found the Los Alamos work stimulating. J. Robert Oppenheimer—theoretical physicist assigned as scientific director of the Manhattan Project by General Groves—charged him with testing the implosion method for setting off atomic bombs. Due to the dangers, Alvarez conducted the tests outside of Los Alamos in nearby Bayo Canyon, observing the initial test from within an army tank. The precautions proved well-founded when the test sent scorching-hot shrapnel in all directions and caught the surrounding woods on fire. Alvarez went on to enjoy a long and distinguished career after the war, winning the 1968 Nobel Prize in Physics.

An engraved stone marks the location of Site A today.

Today, Alvarez’s journey through the Manhattan Project can be retraced at LM sites. Although the structures are gone, an engraved stone marks Site A’s location within the Forest Preserve District of Cook County. Eckhart Hall is now home to the University of Chicago math department. And hikers can traverse Bayo Canyon along Los Alamos County’s trail network. LM honors and remembers the important work that Alvarez and the many other nuclear weapons and uranium workers performed at its sites.

Eckhart Hall on the University of Chicago Campus. While working
out of Eckhart Hall, Alvarez designed a way to detect German
reactors. The hall is part of LM’s Chicago South, Illinois, Site.


Implosion testing in Bayo Canyon (c. 1940s).


Bayo Canyon Today.