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ESRF developments of the Accelerator Toolbox
Nicola Carmignani, ESRFon behalf of the Beam Dynamics group of the ESRF
Accelerator Toolbox collaboration meetingMay 17 2017
OUTLINE
• Pass methods • Turn number and RFCavityPass• Physical apertures and losses• Atplot• Quantum diffusion• Atfastring• Atmatch• Touschek lifetime
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PASS METHODS
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Each PassMethod file has three functions:• The integrator => it does the tracking• The passFunction (or trackFunction) => it is called by atpass and it calls
the integrator• The mexFunction => it is used to call the integrator from the matlab
command windowWith the new AT, both passFunction and the trackFunction can be used, but the trackFunction is faster.
PASS METHODS
The matlab structure of each element is copied to a C structure at turn 0, then the access is faster.The tracking results in being about 20% faster.The turn number is passed to all the integrators through the parameter structure.
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Element structure for StrMPoleSymplectic4Pass
TURN NUMBER AND RFCAVITYPASS
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CavityPass RFCavityPass
With the turn number, the cavity passmethod can be improved. With the new RFCavityPass, changing the RF frequency we change the closed orbit.
PHYSICAL APERTURES AND BEAM LOSSES
Most of the pass methods have two additional optional fields: RAperturesand EApertures, for rectangular and elliptical physical apertures.RApertures=[xlim -xlim ylim -ylim];EApertures=[xlim ylim];
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See R. Versteegen, “Modeling of Beam Losses at ESRF”, IPAC 15
ATPLOT
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Further examples of plotting functions: curly H, beam sizes, closed orbit, physical apertures, W functions, second order dispersion
QUANTUM DIFFUSION
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ATFASTRING
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atfastring creates a lattice with only a few elements:• Linear matrix;• Nonlinear element (chromaticity
and detuning with amplitude);• RF cavity;• Quantum diffusion.
The fast ring can be used for impedance studies and for harmonic cavity studies.
-120 -100 -80 -60 -40 -20 0
ct (mm)
0
1000
2000
3000
4000
5000
6000
7000
8000
charg
e d
ensi
ty (
a.u
.)
With third harmonic cavity
Without harmonic cavity
Simulation done with the atfastring300000 particles200000 turns
ATMATCH
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AT has now a function for general matching, written by Simone Liuzzo: atmatch
Matching an orbit bump with atmatch
Matching of longitudinal gradient dipoles
TOUSCHEK LIFETIME
The function TouschekPiwinskiLifetimecomputes the Touscheklifetime for a lattice, given the momentum acceptance
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Momentum acceptance
CONCLUSION
The version of AT in the sourceforge repository has many new features:• physical apertures and losses information;• atplot;• quantum diffusion;• atfastring;• atmatch;• Touschek lifetime;
It is backwards compatible, it is compatible with the python AT and it is 20% faster!
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Many thanks for your attention
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