Exhibits: End of a War; Beginning of a Laboratory
Z DIVISION
1945-1949

By March of 1949, personnel had increased to over 1400 and the Sandia technical area rang with the sound of construction and a flurry of engineering work. The University of California, manager of Los Alamos, became increasingly uncomfortable about being associated with the engineering aspects of nuclear weapons work. The Atomic Energy Commission began to look for an industrial firm to manage the engineering facility. On May 13, 1949, President Harry Truman asked AT&T to accept managerial responsibility of Sandia. It was agreed that AT&T's manufacturing arm, Western Electric, would accept the management role on a no-profit, no-fee basis. Sandia Corporation, a wholly owned subsidiary of Western Electric, was formed to manage the lab. On November 1, 1949 the official change occurred. AT&T maintained the contract until 1993 when Martin Marietta (now Lockheed Martin) took over. Sandia continued to evolve over the years, becoming Sandia National Laboratories in 1979 and continually expanding into new areas of research as its expertise allows

	Aerial view of the Albuquerque Airport looking east c. 1930. There is a certain peace in the vast emptiness of this area. By mid-1945, the silence had been replaced by construction and bustle.
	Future Sandian Ben Benjamin at Los Alamos. Benjamin enlisted in the Army and, because of his technical background, was assigned to the Special Engineering Detachment stationed at Los Alamos along with several other future Sandians. His experience with prisms placed him in the technical photographic group. After the war, Benjamin mustered out of the Army and returned to college to get his degree before returning to Sandia for a 39-year career. (Photo courtesy of LANL)
	The dawn of the nuclear age. This sequence of photographs shows the Trinity fireball beginning to form as clouds gather in the sky above the explosion. (Photo courtesy of LANL)
	The scars of the Trinity Test. The lighter circle was made by the practice blast of 100 tons of TNT in May of 1945. The darker circle is the mark of the Trinity shot. (Photo courtesy of LANL)
	Glenn Fowler's 1945 notebook indicates the variety of tasks involved as Z Division settled and expanded at Sandia Base. With Dale Corson, Fowler organized Z Division's testing group. This was the first group to move to Albuquerque, and Fowler's concerns covered everything from his own rent through the removal of equipment from the Wendover site.
	At war's end, thousands of the planes built in America's wartime factories were worn out and slated for destruction. The government's Reconstruction Finance Corporation was in charge of disposing of war surplus. The Albuquerque base served as one collection and destruction point. (Photo courtesy of J. J. Miller)
	Early Sandians approach a security gate. Dirt roads and wooden buildings marked the Z Division working environment.
	Bob Henderson took over as temporary Director of Z Division in January 1947. As Chief Engineer, he played a crucial role in the Manhattan Project and in establishing Z Division at Sandia Base. After Paul Larsen became Director, Henderson continued his high-profile role at Sandia, retiring as a Vice President in 1974.
	The security system at the Laboratory included guard towers until the 1950s.
	Felix Padilla's cartoons graced the cover of the early Sandia Laboratory Weekly Bulletin. Only 4 pages long, the early editions were mimeographed. In 1951 the first letterpress copies were produced and the Bulletin appeared every other week. On January 1, 1954, the Bulletin became the Sandia Lab News.
	Paul Larsen became director of Z Division in December of 1947. He presided over the promotion of Z Division to Sandia Laboratory, a separate branch of Los Alamos. He was director of Sandia until 1949. During his tenure a $25 million construction effort was begun to build permanent structures on the site.
	In 1948 Z Division became Sandia Laboratory, a branch of Los Alamos.
	Building 800 opened in 1949. A symbol of the transfer from a rapidly growing, war-minded operation to a stable, permanent engineering laboratory, 800 houses Sandia's main administrative offices.

The Trinity test and the massive destruction at Hiroshima and Nagasaki left little doubt of the effectiveness of atomic weapons against land targets. At the war's end, however, there was still speculation about what this powerful new weapon meant for the world's naval fleets. As a result, plans were made to test the fourth and fifth atomic devices against a target fleet in the lagoon of Bikini Atoll in the Pacific during the summer of 1946. Dubbed Operation Crossroads, this operation was a joint effort of the military services. Los Alamos was responsible for furnishing the atomic devices, assembling them, and running practice tests. As the ordnance and assembly arm of Los Alamos, Z Division provided personnel for the tests and Sandia Base temporarily became a ghost town as much of its population headed for the Pacific. There were two test shots. The Able test was an airdrop of a Fat Man-style bomb on June 30, 1946 that sank five of the target vessels. The Baker detonation on July 25, 1946 was the first underwater nuclear explosion. It sank nine vessels, including a battleship and an aircraft carrier. But the radioactive contamination spread over the target vessels by the spray from the blast kept inspection parties from boarding most of them four days after the test. This was not taken as an indication of naval obsolescence but of the need for some design changes and for the installation of radiation washdown systems. The atomic bomb was not yet considered an efficient weapon for use against a fleet at sea.

	Roger Warner at his shipboard command post during Operation Crossroads. Warner served as director of Z Division after Zacharias left in 1945. He himself left late in 1946 to join the Atomic Energy Commission as director of engineering.
	Members of the Z Division Assembly Group in the Pacific during Operation Crossroads. Seated in the front row, left to right: Phil Dailey, Kenneth O. Roebuck, Arthur Machen, Ira "Tiny" Hamilton, and Bryan Arthur. Back row, left to right: Roger S. Warner, Major Robert L. Roark, Colonel Jack Sutherland (seated), Glenn Fowler (kneeling), Alvin Van Vessem, William O. McCord, and Gene Eyster (seated).
	Dave's Dream being loaded for the Able test drop during Operation Crossroads in the Pacific. Secrecy required the white canvas screens to block observation of the bomb-loading operation. The B-29 dropped a Fat Man-style bomb at the test.
	An aerial view of the Baker shot of Operation Crossroads. The underwater blast formed the familiar mushroom cloud. Nine of the ships placed in the area for the test were sunk while mist and spray covered other target vessels with radioactive contamination.

From 1905-1907 the Colorado River changed its course, flooding part of southern California's Imperial Valley and forming the inland sea now called the Salton Sea. The sea proved a useful water target for practice bomb drops during World War II. After the war, efforts to continue refining atomic weapon designs required the use of an adequate field-test range and it was recommended that the Los Alamos Laboratory continue using Salton Sea. Responsible for ordnance design and field testing, Z Division was placed in charge of technical activities at the Sea. Although Salton Sea continued to be a useful water target, the need for a land target became increasingly obvious through the 1950s and a new site was selected near Tonopah, Nevada. A gradual transition was made out of Salton Sea and Sandia gave up responsibility for the Sea in 1961.

	The Instrument Lab was the center of test operations at Salton Sea Test Base. Dave Tarbox, project engineer, designed the building. Salton Sea was used by Z Division and then Sandia from 1946 to 1961.
	Tommy Thompson running a Mitchell camera at Henry Station (a temporary station) at Salton Sea Test Base in 1948. Used primarily for Hollywood filmmaking, the Mitchell Camera had a 1,000 ft. magazine and was adopted for test filming because it was the best available.