Proton Synchrotron Booster

The Proton Synchrotron Booster ( Abbreviation: PSB ) is a synchrotron particle accelerator at CERN. He was put into operation in 1972 and consists of four stacked beamlines, each forming a ring with 25 m radius. The Proton Synchrotron Booster is the pre-accelerator of the larger proton synchrotron. Protons are conducted with an energy of 50 MeV in the PSB where they are accelerated to 1.4 GeV and then forwarded to the proton synchrotron. The construction of the PSB, the number of protons could be increased sixfold in the PS.

History

Construction began in 1968 and on 26 May 1972, the first protons were accelerated to the then maximum energy of 800 MeV. Reason for the construction of the Proton Synchrotron Booster was the need for a higher number of protons for the proton synchrotron, which increases by the chosen design of the four stacked rings of the PSB to 1013 protons per pulse (2.5 · 1012 per ring ) in the mid 1970s could be; until then the PS reached 1.6 × 1012 protons per pulse. Other improvements eventually the supply of a total of 4.25 · 1013 protons per pulse by the PSB has been reached.

From the early 1980s, the PSB was also used for the acceleration of deuterium, helium, sulfur and oxygen ions, which were fed by the then linear accelerator LINAC 1 in the PSB. With the commissioning of the supplies specifically designed for ion linear accelerator LINAC 3, heavier ions were accelerated as, for example, indium or lead in the PSB. Today, the PSB is to no longer used because the supply of ions in the PS from the LINAC 3 now on the Low Energy Ion Ring ( Leir ) is carried out.

1992, the maximum energy of the accelerated protons was increased to 1.0 GeV and due to the increased requirements of the Large Hadron Collider in early 2000 - to its Vorbeschleunigerkette the PSB belongs since 2008 - increased to 1.4 GeV on. In connection with the commissioning of the under construction new linear accelerator LINAC 4 that future particles with 160 MeV (currently with 50 MeV LINAC 2 ) is intended to feed into the PSB, a further conversion to a maximum energy of 2.0 GeV is planned.

From 1989 to 1992 moved to the device for the production of radioactive ion beams ISOLDE ( Isotope Separator On Line Device) to the PSB, which has been fed since the 1960s by former Synchro - Cyclotron (SC) with accelerated to 600 MeV protons. Today there proton beam of the PSB to 1.4 GeV is used to produce the radioactive ion beams.

Operation

Proton pulse of the linear accelerator is decomposed with the aid of successive pulsed magnets vertically in six sub-beams, wherein the first and last of the rising or falling edge of the pulse corresponds to the proton and is not used. The middle four beams are then directed ray tubes using other magnets in the individual vertically one above the other. For increasing the number of protons per packet or the number of packets per ring proton, the operation is repeated several times. In the past five packages were each filled per ring and today usually one or two packets in two to ten repetitions per package.

After the 1,2 -second acceleration and additional spatial synchronization of the proton bunches - these are then exactly in all ray tubes one above the other - these are again coupled with the help of special pulsed magnets successively that each revolution the existing proton packs a ring are extracted. The total extraction of four rings occurs at 1.4 GeV so within 2291.2 ns ( four times the orbital period of 572.8 ns). Depending on the requirement of the packet number and sequence only individual rings are used to accelerate or more than four proton bunches of two panels, each with one proton per packet ring in the PS fed ( eg for the LHC 4 2 packages).