Operational performance of the CERN injector complex with transversely split beams

Abstract

With the progress made in 2015, the beams produced by the CERN Proton Synchrotron using multiturn extraction (MTE) have been delivered to the Super Proton Synchrotron (SPS) for the fixed-target physics run. Operation successfully started in the second half of September 2015 and continued until the end of the proton physics program by mid November. In this paper the overall performance and beam quality is discussed in detail considering the complete chain of accelerators, from the PS-Booster to the SPS. Moreover, a thorough comparison of the global performance of the MTE scheme against the previously used technique, the so-called continuous transfer (CT), is also carried out.

Numerical simulations of electron cloud build-up in circular accelerators in the presence of multimode distribution beams

“…The bunch intensity and the bunch length also influence the EC dynamics, as they change the force acting on the electrons from the beam, whereas the transverse emittances have a milder impact [6]. This, does not exclude that special transverse beam distributions might have a strong impact on EC phenomena, which is the aspect addressed by our study and profits from the recent studies on the PS Multi-Turn Extraction (MTE) [16,17,18,19,20,21,22,23,24], where transverse beam splitting by means of adiabatic resonance crossing is performed. Indeed, beam splitting can be used to generate multimode beam distributions in the horizontal plane, which in turn can be used to manipulate the EC generation thus contributing to a more efficient surface conditioning.…”

“…Indeed, beam splitting can be used to generate multimode beam distributions in the horizontal plane, which in turn can be used to manipulate the EC generation thus contributing to a more efficient surface conditioning. The generation of charged particle beams with multimode transverse distribution was pushed with MTE [16] that was studied at the CERN PS [17,18,19,20] and became recently fully operational [21,22,23,24] for the transfer of proton beams from the PS to the SPS in the framework of the fixed-target physics programme. The original idea [16] discussed the possibility of splitting a single-Gaussian beam into a multi-Gaussian one by means of particles' trapping into stable islands of phase space.…”

Numerical investigation of space charge effects on the positions of beamlets for transversely split beams

“…However, it is also possible to consider special configurations in which the intensity sharing between the outer beamlets and the central one is not even. This generates another class of configurations that can be classified by means of the socalled MTE efficiency [10][11][12]…”

“…In the course of experimental studies aimed at preparing the operation of MTE at the PS [8,9] (see also [10][11][12] for a summary of the MTE performance since it became operational in the second half of 2015), the impact of space charge on the beam characteristics was considered and a measurement campaign was carried out, whose results are reported in [13]. The observations can be summarized as follows (see Fig.…”

Transverse beam splitting made operational: Key features of the multiturn extraction at the CERN Proton Synchrotron

“…Since then, it has successfully replaced the CT extraction. It is worth mentioning that a complete account of the performance analysis of MTE in the PSB, and the PS and SPS rings has been carried out and can be found in [8,9], respectively. This paper addresses the aspects related to the transverse splitting and its fluctuations in Sec.…”