A new set of magnetic septa in the CERN PS complex

Over the last few years the CERN PS Complex has been upgraded to fulfill the requirements of two major projects : (i) - producing and transferring lead ions to the SPS for high energy physics experiments and (ii) raising the PSB to PS transfer energy from 1 to 1.4 GeV to generate the high brightness beam for the LHC. To cope with the tight demands imposed by these upgrades, ten magnetic septa, operating under vacuum in the PSB and the PS have been redesigned and progressively replaced. The new devices are bakeable, better suited to high vacuum operation and with higher performance. This paper reports the main characteristics and technological advantages of these magnets together with their present performance

Consolidation project of the electrostatic septa in the CERN PS ring

After almost two decades of reliable service, the electrostatic septa of the CERN PS complex need to be upgraded. This is to fulfil the increased requirements on vacuum performance and the need to reduce the time spent on maintenance interventions. Two electrostatic septa are used in the PS ring: septum 23 is used for a resonant slow extraction, while septum 31 is used for the so-called 'continuous transfer' (CT) 5-turn extraction. This paper describes the experience gained with these septa over the years. We report the main characteristics and technological advantages of the new septum 23 together with its present performance

The Septa for LEIR Extraction and PS Injection

The Low Energy Ion Ring (LEIR) is part of the CERN LHC injector chain for ions. The LEIR extraction uses a pulsed magnetic septum, clamped around a metallic vacuum chamber. Apart from separating the ultra high vacuum in the LEIR ring from the less good vacuum in the transfer line to the PS this chamber also serves as magnetic screen and retains the septum conductor in place. The PS ion injection septum consists of a pulsed laminated magnet under vacuum, featuring a single-turn water cooled coil and a remote positioning system. The design, the construction and the commissioning of both septa are described

Injection and extraction magnets: septa

An accelerator has limited dynamic range: a chain of accelerators is required to reach high energy. A combination of septa and kicker magnets is frequently used to inject and extract beam from each stage. The kicker magnets typically produce rectangular field pulses with fast rise- and/or fall-times, however the field strength is relatively low. To compensate for their relatively low field strength, the kicker magnets are generally combined with electromagnetic septa. The septa provide relatively strong field strength but are either DC or slow pulsed. This paper discusses injection and extraction systems with particular emphasis on the hardware required for the septa.Comment: 18 pages, presented at the CERN Accelerator School CAS 2009: Specialised Course on Magnets, Bruges, 16-25 June 200

PS2 Beam Transfer Systems: Conceptual Design Considerations

The replacement of CERN's existing 26 GeV Proton Synchrotron (PS) machine with a separated function synchrotron PS2 has been identified as an important part of the future upgrade of the CERN accelerator complex [1,2]. The PS2 will require the design of a number of beam transfer systems associated with injection, extraction, beam dumping and transfer. The different requirements are briefly presented. A first iteration of the conceptual design aspects of these systems is presented, based on the initial PS2 parameter set [3] and assuming a simple 90-degree phase advance FODO lattice. The required equipment sub-system performance is derived and discussed, and possible limitations are analysed. The impact on the overall design and parameter set is discussed, together with some recommendations for the direction of the continuing studies

Septa and Distributor Developments for H- Injection into the Booster from LINAC4

The construction of Linac4 requires the modification of the existing injection system of the CERN PS Booster. A new transfer line will transport 160 MeV H- ions to this machine. A system of 5 pulsed magnets (BIDIS) and 3 vertical septa (BISMV) will distribute and inject the Linac pulses into the four-vertically separated Booster rings. Subsequently the beam will be injected horizontally, using a local bump created with bumpers (BS magnets) to bring the injected H- beam together with the orbiting proton beam onto the stripper foil. To accommodate the injected H- beam, the first of the BS magnets will have to be a septum-like device, deflecting only the orbiting beam. This paper highlights the requirements and technical issues and describes the solutions to be adopted for both the BIDIS and BISMV. The results of initial prototype testing of the BIDIS magnet will also be presented

Fast Injection into the PS2

The conceptual considerations of a fast injection system for protons and ions in the proposed PS2 accelerator are presented. Initial design parameters of the injection septum and kicker systems are derived, taking into account rise and fall times, apertures and machine optics. The requirements for an injection dump used for failures are described. Possible limitations and technical issues are outlined

Operational considerations for the PSB H- Injection System

For the LINAC4 project the PS Booster (PSB) injection system will be upgraded. The 160 MeV Hbeam will be distributed to the 4 superimposed PSB synchrotron rings and horizontally injected by means of an H- charge-exchange system. Operational considerations for the injection system are presented, including expected beam losses from unwanted field stripping of H- and excited H0 and foil scattering, possible injection failure cases and expected stripping foil lifetimes. Loading assumptions for the internal beam dumps are discussed together with estimates of doses on various components

Layout considerations for the PSB H- injection system

The layout of the PSB H- injection system is described, including the arguments for the geometry and the required equipment performance parameters. The longitudinal positions of the main elements are specified, together with the injected and circulating beam axes. The assumptions used in determining the geometry are listed

Development of an Eddy Current Septum for LINAC4

A linear accelerator (linac) is the first stage of the CERN accelerator complex. The linac defines the beam quality for subsequent stages of acceleration and the reliability has to be high as a fault of the linac shuts down all other machines. The existing linacs at CERN were designed 30 or more years ago: recent upgrades allowed the linacs to reach LHC requirements but also showed that they are at the limit of their brightness and intensity capabilities. A replacement Superconducting Proton Linac (SPL) has been proposed; the initial part of the SPL is termed LINAC4. The LINAC4 injection bump would be made up of a set of four pulsed dipole magnets; the first of these magnets (BS1) must act as a septum with a thin element dividing the high-field region of the circulating beam from the field-free region through which injected $H^{-}$ beam must pass. The initial specifications for BS1 required; a deflection of 66 mrad at 160 MeV, achieved with a peak field of 628 mT and a length of 250 mm: the field fall time was $40 \mu$s with a flattop of at least $100 \mu$s. The ripple of the flattop should be below ±1%. This paper discusses the design of an eddy current septum for BS1