Matthew Fraser

Machine development studies for PSB extraction at 160 MeV and PSB to PS beam transfer

This paper collects the machine development (MD) activities for the beam transfer studies in 2016 concerning the PSB extraction and the PSB-to-PS transfer. Many topics are covered: from the 160 MeV extraction from the PSB, useful for the future commissioning activities after the connection with Linac4, to new methodologies for measuring the magnetic waveforms of kickers and dispersion reduction schemes at PS injection, which are of great interest for the LHC Injectors Upgrade (LIU) [1] project.

JACoW : Phase Space Folding Studies for Beam Loss Reduction During Resonant Slow Extraction at the CERN SPS

The requested number of protons slow-extracted from the CERN Super Proton Synchrotron (SPS) for Fixed Target (FT) physics is expected to continue increasing in the coming years, especially if the proposed SPS Beam Dump Facility is realised. Limits on the extracted intensity are already being considered to mitigate the dose to personnel during interventions required to maintain the extraction equipment, especially the electrostatic extraction septum. In addition to other on-going studies and technical developments, a reduction of the beam loss per extracted proton will play a crucial role in the future performance reach of the FT experimental programme at the SPS. In this paper a concept is investigated to reduce the fraction of beam impacting the extraction septum by folding the arm of the phase space separatrix. Beam dynamics simulations for the concept are presented and compared to the phase space acceptance of the extraction channel. The performance potential of the concept at SPS is evaluated and discussed alongside the necessary changes to the non-linear optical elements in the machine.

Analysis of the SPS Long Term Orbit Drifts

The Super Proton Synchrotron (SPS) is the last accelerator in the Large Hadron Collider (LHC) injector chain, and has to deliver the two high-intensity 450 GeV proton beams to the LHC. The transport from SPS to LHC is done through the two Transfer Lines (TL), TI2 and TI8, for Beam 1 (B1) and Beam 2 (B2) respectively. During the first LHC operation period Run 1, a long term drift of the SPS orbit was observed, causing changes in the LHC injection due to the resulting changes in the TL trajectories. This translated into longer LHC turnaround because of the necessity to periodically correct the TL trajectories in order to preserve the beam quality at injection into the LHC. Different sources for the SPS orbit drifts have been investigated: each of them can account only partially for the total orbit drift observed. In this paper, the possible sources of such drift are described, together with the simulated and measured effect they cause. Possible solutions and countermeasures are also discussed.

Beam Commissioning of the HIE-ISOLDE Post-Accelerator

Phase 1a of the High Intensity and Energy ISOLDE (HIE-ISOLDE) project [1] was completed in 2015. The first cryomodule and two High Energy Beam Transfer lines (HEBT) were installed. In addition, many of the subsystems of the normal conducting part of the postaccelerator (REX) were renovated or refurbished. Following the hardware commissioning of the different systems [2] and, in preparation for the start of the physics program, many tests and measurements were conducted as part of the beam commissioning program. The results of these tests and the plan for the next beam commissioning campaign are discussed in this paper.