ISABELLE

ISABELLE (also known later as Colliding Beam Accelerator, CBA) was a 200+200 GeV proton–proton colliding beam particle accelerator partially built by the United States government at Brookhaven National Laboratory in Upton, New York, before it was cancelled in July, 1983. Colliding beam accelerators A colliding beam, storage ring accelerator was first proposed by Gerard O'Neill of Princeton in 1956, who built an electron-electron system beginning in 1957 (operational in 1962, first collisions in 1964) with assistance from Burton Richter, William C. Barber and Bernard Gittelman. The AdA accelerator, an electron-positron system, stored its first beam in 1961 at Frascati National Laboratories, Italy and was later moved to Orsay Laboratory, France, where in 1964 it recorded first e+e− collisions. At the same time, two colliding-beam experiments were conceived and built by Budker and his group at the Institute of Nuclear Physics in Novosibirsk, Russia, Soviet Union: electron-electron VEP-1 (first collisions in 1964) and electron-positron VEPP-2 (first collisions in 1965). The idea of using alternating gradient synchrotron (AGS) technology to build storage rings for a proton-proton colliding beam accelerator was considered at a summer study held at Brookhaven in 1963. The Intersecting Storage Rings (ISR) facility at CERN, a 30+30 GeV proton-proton system, opened in 1971 and became the first high energy hadron collider. The SPEAR collider at the Stanford Linear Accelerator Center, a 3+3 GeV electron-positron system, was completed in 1972 and soon contributed to discoveries of the ψ meson and τ lepton, both recognized in Nobel Prizes. The ψ had previously been found in a fixed-target experiment at the Brookhaven AGS, where it was called the J, but it was better measured with SPEAR. The ISABELLE project A design study for a proton storage ring system was completed at Brookhaven in 1973. In 1974 the U.S. High Energy Physics Advisory Panel recommended that ISABELLE (the Intersecting Storage Accelerator + "belle") should be built at Brookhaven. It was to be a 200+200 GeV proton-proton system using superconducting magnets. New York politicians, spurred by the sometimes impetuous Sen. Moynihan, pushed through funding before development of magnet technology had been completed. Construction began in 1978. The following year a prototype magnet was successfully tested.