SixTrack V and runtime environment

Abstract

SixTrack is a single-particle tracking code for high-energy circular accelerators routinely used at CERN for the Large Hadron Collider (LHC), its luminosity upgrade (HL-LHC), the Future Circular Collider (FCC) and the Super Proton Synchrotron (SPS) simulations. The code is based on a 6D symplectic tracking engine, which is optimized for long-term tracking simulations and delivers fully reproducible results on several platforms. It also includes multiple scattering engines for beam–matter interaction studies, as well as facilities to run the integrated simulations with external particle matter interaction codes. These features differentiate SixTrack from general-purpose, optics-design software. The code recently underwent a major restructuring to merge the advanced features into a single branch, such as multiple ion species, interface with external codes and high-performance input/output. This restructuring also removed a large number of compilation flags, instead enabling/disabling the functionality with runtime options. In the process, the code was moved from Fortran 77 to Fortran 2018 standard, also allowing and achieving a better modularization. Physics models (beam–beam effects, Radio-Frequency (RF) multipoles, current carrying wires, solenoid and electron lenses) and methods (symplecticity check) have also been reviewed and refined to offer more accurate results. The SixDesk runtime environment allows the user to manage the large batches of simulations required for accurate predictions of the dynamic aperture. SixDesk supports several cluster environments available at CERN as well as submitting jobs to the LHC@Home volunteering computing project, which enables volunteers contributing with their hardware to CERN simulation. SixTrackLib is a new library aimed at providing a portable and flexible tracking engine for single- and multi-particle problems using the models and formalism of SixTrack. The library is able to run in CPUs as well as graphical processing units (GPUs). This contribution presents the status of the code, summarizes the main existing features and provides details about the main development lines SixTrack, SixDesk and SixTrackLib.

Impact of Field Errors of Quadrupole Units on Beam Losses at SIS100 Injection

“…The full beam dynamics simulations of a single bunch in SIS100 with nonlinear space charge, nonlinear thin-lens tracking and nonlinear RF bucket are carried out using the open source CERN code SixTrackLib [4,5,6]. The full SIS100 lattice [7] is simulated based on the heavy-ion fast extraction tune settings, where the working point is scanned in 0.01 intervals across the tunes 18.55 ≤ Q x,y < 19.…”

Absence of Structure Resonances in SIS100 Tune Quadrant for Heavy Ion Fast Extraction

“…The full beam dynamics simulations of a single bunch in SIS100 with nonlinear space charge, nonlinear thin-lens tracking and nonlinear RF bucket are carried out using the open source CERN code SixTrackLib [1,2,3]. The full SIS100 lattice [4] is simulated based on the heavy-ion fast extraction tune settings, where the working point is scanned in 0.01 intervals across the tunes 18.55 ≤ Q x,y < 19.…”

Non-linear dynamics modelling in accelerators with the use of symplectic integrators

“…the stability of the C S AB A m & C SB AB m integrators is guaranteed even for large integration steps. These new symplectic integrators (C S AB A m & C SB AB m ) are successfully used in different dynamical problems [67,77,79] but never compared with the standard integration schemes like the ones used by MAD-X [62] and SixTrack [61].…”

“…(2.86b)) often used in multi-particle studies that requiring a fast beam transport routine. In our case, the method is applied to the LHC and benchmarked against tracking simulations from the SixTrack symplectic tracking code [61].…”

“…The HO and BBLR kicks at IP2 and IP8 are not included in the simulations since they are quite weaker than the ones in IP1 and IP5. No magnet imperfections are considered and the tracking simulations are done with SIXTRACK code[61], where thin kicks are used.5.3 Numerical optimization of the DC wire for best compensation of the long range beam-beam interactions HL-LHC baseline and ultimate scenario at the end of the luminosity levelingStarting with the HL-LHC baseline scenario at the end of the luminosity leveling with half crossing angle at IP1/250 µrad, Landau octupoles set at I o = −300 A for partial compensation of the leading order octupole-like TSA χ from the BBLR kicks (as it was the case at the last runs of the LHC[102]) and optimized working point Q = (62.315, 60.32)[101], the DA min without the use of DC wires is min(DA I w =0 ) = 6.1 σ as shown in Fig.5.6a (and also from the blue line in Fig.5.1b). Making use of the DC wires, the DA min can be improved up to ∆ DA min = 0.7 σ with configurations that comply with the machine protection restrictions (D w > 10.4 σ).…”