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In page SLAC National Accelerator Laboratory:

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Founded in 1962 as the Stanford Linear Accelerator Center, the facility is located on 172 ha (426 acres) of Stanford University-owned land on Sand Hill Road in Menlo Park, California, just west of the university's main campus. The main accelerator is 3.2 km (2 mi) long,[1]: 55  making it the longest linear accelerator in the world,[citation needed] and has been operational since 1966.