The BEBC coils created a strong magnetic field of 3.5 T over the sensitive volume of the chamber. The magnet coils were fabricated at CERN using copper-reinforced niobium–titanium superconductor cable. The chamber body was surrounded by the then-largest superconducting solenoid magnet of two coils in a Helmholtz arrangement. The BEBC project was launched in 1966 by CERN, France ( Saclay), and Germany ( DESY) and installed at CERN in the early 1970s. The conception and construction of giant bubble chambers such as Gargamelle and BEBC was based on know-how acquired through the construction and operation of smaller bubble chambers such as the 30 cm hydrogen chamber, which came into operation at CERN in 1960, and the 2 m hydrogen chamber four years later. The bubble chamber was then ready again for a new cycle of beam exposure. After each expansion, the pressure was increased again to stop the boiling. The stereo photographs were subsequently scanned and all events finally evaluated by a team of scientists. These tracks were photographed by the five cameras mounted on top of the chamber. ĭuring each expansion, charged particles ionized the atoms of the liquid as they passed through it and the energy deposited by them initiated boiling along their path, leaving trails of tiny bubbles. The piston expansion, synchronized with the charged particle beam crossing the chamber volume, caused a rapid pressure drop in consequence the liquid reached its boiling point. The liquids at typical operation temperatures around 27 K were placed under overpressure of about 5 standard atmospheres (510 kPa). The chamber body, a stainless-steel vessel, was filled with 35 cubic metres of superheated liquid hydrogen, liquid deuterium, or a neon-hydrogen mixture, whose sensitivity was regulated by means of a movable piston weighing 2 tons. The Big European Bubble Chamber ( BEBC) is a large detector formerly used to study particle physics at CERN. The Big European Bubble Chamber on display at the Microcosm museum
0 kommentar(er)
