LHC@Home (SixTrack): LHC@Home - SixTrack Project News

The members of the SixTrack project from LHC@Home would like to thank all the volunteers who made their CPUs available to us! Your contribution is precious, as in our studies we need to scan a rather large parameter space in order to find the best working points for our machines, and this would be hard to do without the computing power you all offer to us!

Since 2012 we have started performing measurements with beam dedicated to probing what we call the “dynamic aperture” (DA). This is the region in phase space where particles can move without experiencing a large increase of the amplitude of their motion. For large machines like the LHC this is an essential parameter for granting beam stability and allowing long data taking at the giant LHC detectors. The measurements will be benchmarked against numerical simulations, and this is the point where you play an important role! Currently we are finalising a first simulation campaign and we are in the process of writing up the results in a final document. As a next step we are going to analyse the second half of the measured data, for which a new tracking campaign will be needed. …so, stay tuned!

Magnets are the main components of an accelerator, and non-linearities in their fields have direct impact on the beam dynamics. The studies we are carrying out with your help are focussed not only on the current operation of the LHC but also on its upgrade, i.e. the High Luminosity LHC (HL-LHC). The design of the new components of the machine is at its final steps, and it is essential to make sure that the quality of the magnetic fields of the newly built components allow to reach the highly demanding goals of the project. Two aspects are mostly relevant:

specifications for field quality of the new magnets. The criterion to assess whether the magnets’ filed quality is acceptable is based on the computation of the DA, which should larger than a pre-defined lower bound. The various magnet classes are included in the simulations one by one and the impact on DA is evaluated and the expected field quality is varied until the acceptance criterion of the DA is met.

dynamic aperture under various optics conditions, analysis of non-linear correction system, and optics optimisation are essential steps to determine the field quality goals for the magnet designers, as well as evaluate and optimise the beam performance.

The studies involve accelerator physicists from both CERN and SLAC.

Long story made short, the tracking simulations we perform require significant computer resources, and BOINC is very helpful in carrying out the studies. Thanks a lot for your help!
The SixTrack team

Latest papers:

R. de Maria, M. Giovannozzi, E. McIntosh (CERN), Y. Cai, Y. Nosochkov, M-H. Wang (SLAC), DYNAMIC APERTURE STUDIES FOR THE LHC HIGH LUMINOSITY LATTICE, Presented at IPAC 2015.
Y. Nosochkov, Y. Cai, M-H. Wang (SLAC), S. Fartoukh, M. Giovannozzi, R. de Maria, E. McIntosh (CERN), SPECIFICATION OF FIELD QUALITY IN THE INTERACTION REGION MAGNETS OF THE HIGH LUMINOSITY LHC BASED ON DYNAMIC APERTURE, Presented at IPAC 2014

Latest talks:

Y. Nosochkov, Dynamic Aperture and Field Quality, DOE review of LARP, FNAL, USA, July 2016
Y. Nosochkov , Field Quality and Dynamic Aperture Optimization, LARP HiLumi LHC collaboration meeting, SLAC, USA, May 2016
M. Giovannozzi, Field quality update and recent tracking results, HiLumi LHC LARP annual meeting, CERN, October 2015
Y. Nosochkov, Dynamic Aperture for the Operational Scenario Before Collision, LARP HiLumi LHC collaboration meeting, FNAL, USA, May 2015

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