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<!--HTML--><br />This klystron has been specially designed to be used as an RF source in particle accelertators. It is a five-cavity, high-gain, sealed-off klystron amplifier, able to deliver 17.5 kW of minimum average power and 35 MW minimum peak power at 2998.5 MHz. The maximum RF pulse duration available from this high-power klystron is 4.5 µsec. This klystron includes an ion pump, which ensures a continuous high vacuum. <br />Used in the LEP injector LP1.

Prototype of UA1 central detector inside a plexi tube. The UA1 experiment ran at CERN's Super Proton Synchrotron and made the Nobel Prize winning discovery of W and Z particles in 1983. The UA1 central detector was crucial to understanding the complex topology of proton-antiproton events. It played a most important role in identifying a handful of Ws and Zs among billions of collisions. The detector was essentially a wire chamber - a 6-chamber cylindrical assembly 5.8 m long and 2.3 m in diameter, the largest imaging drift chamber of its day. It recorded the tracks of charged particles curving in a 0.7 Tesla magnetic field, measuring their momentum, the sign of their electric charge and their rate of energy loss (dE/dx). Atoms in the argon-ethane gas mixture filling the chambers were ionised by the passage of charged particles. The electrons which were released drifted along an electric field shaped by field wires and were collected on sense wires. The geometrical arrangement of the 17000 field wires and 6125 sense wires allowed a spectacular 3-D interactive display of reconstructed physics events to be produced.

A full box of small light guides A full box of small light guides.Light guides like this are used to carry signals to the electronics for recording.

The SC (synchro-cyclotron) was the first accelerator built at CERN. It operated from August 1957 until it was closed down at the end of 1990.

First proton source used at CERN's Proton Synchrotron (PS) which started operation in 1959. The PS was CERN’s first synchrotron. Activated in 1959, it was initially CERN's flagship accelerator, but when the laboratory built new accelerators in the 1970s, the PS’s principal role became to supply particles to the new machines. In the course of its history, it has juggled many different kinds of particles, feeding them directly to experiments or to more powerful accelerators. It is CERN's oldest accelerator still functioning today (2025). It is part of the accelerator chain that supplies proton beams to the Large Hadron Collider. With a circumference of 628 metres, the PS has 277 conventional (room-temperature) electromagnets, including 100 dipoles to bend the beams round the ring. The accelerator operates at up to 26 GeV. In addition to protons, it has accelerated alpha particles (helium nuclei), oxygen, sulphur, argon, xenon and lead nuclei, electrons, positrons and antiprotons. The source is a Thonemann type. In order to extract and accelerate the protons at high energy, a high frequency electrical field is used (140Mhz). The field is transmitted by a coil around a discharge tube in order to maintain the gas hydrogen in a ionised state. An electrical field pulse, in the order of 15kV, is then applied via an impulse transformer between anode and cathode of the discharge tube. The electrons and protons of the plasma formed in the ionised gas in the tube, are then separated. Currents in the order of 200mA during 100 microseconds have been obtained with this type of source.

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<10>photomultiplier tubes. A device to convert light into an electric signal (the name is often abbreviated to PM). Photomultipliers are used in all detectors based on scintillating material (i.e. based on large numbers of fibres which produce scintillation light at the passage of a charged particle). A photomultiplier consists of 3 main parts: firstly, a photocathode where photons are converted into electrons by the photoelectric effect; secondly, a multiplier chain consisting of a serie of dynodes which multiply the number of electron; finally, an anode, which collects the resulting current.

Engineering model used for the construction of the OPAL detector at the LEP accelerator.Scale=1/10

Model of the LEP tunnel as it is in the 1990's. LEP(Large Electron Positron collider) was the world biggest accelerator.

This is a collision region from the world’s first proton collider, the Intersecting Storage Rings. The ISR was used at CERN from 1971-84 to study proton-proton collisions at the highest energy then available (60GeV). When operational, ISR collision regions were surrounded by detectors as shown in the photo. In 1972, the surprising discovery of fragments flying out sideways from head-on proton-proton collisions was the first evidence of quark-quark scattering inside the colliding protons . This was similar to Rutherford’s observation in 1911 of alpha particles scattering off the tiny nucleus inside atoms of gold. The ISR beamtubes had to be as empty as outer space, a vacuum 100 000 times better than other CERN machines at the time.