[FFA_CEBAF_Collab] Identification of Magnetic Field Errors in Synchrotrons based on Deep Lie Map Networks

[Jay Benesch]

Since this is based on MAD-X/SixTrackLib it might be useful for the FFA error analysis and later to set corrector dipoles and quads when built.   Synchrotrons have a lot more passes, of course.  The size of the errors chosen, page 6, is interesting.   Different from the approach taken so far as I understand it, using absolute values of errors rather than fractions of tune and chromaticity.  YMMV

I trust everyone is aware of the ARDAP FOA https://science.osti.gov/ardap/Funding-Opportunities  
https://science.osti.gov/ardap/-/media/grants/pdf/foas/2023/SC_FOA_0002951.pdf 
and that this group will NOT apply until the energy upgrade effort appears in the LRP, given response last year.  
 
https://arxiv.org/abs/2301.04914

Identification of Magnetic Field Errors in Synchrotrons based on Deep Lie Map Networks
Conrad Caliari, Adrian Oeftiger, Oliver Boine-Frankenheim

    Magnetic field errors pose a limitation in the performance of synchrotrons, as they excite non-systematic resonances, reduce dynamic aperture and may result in beam loss. Their effect can be compensated assuming knowledge of their location and strength. Established identification procedures are based on orbit response matrices or resonance driving terms. While they sequentially build a field error model for subsequent accelerator sections, a method detecting field errors in parallel could save valuable beam time. We introduce deep Lie map networks, which enable construction of an accelerator model including multipole components for the magnetic field errors by linking charged particle dynamics with machine learning methodology in a data-driven approach. Based on simulated beam-position-monitor readings for the example case of SIS18 at GSI, we demonstrate inference of location and strengths of gradient and sextupole errors for all accelerator sections in parallel. The obtained refined accelerator model may support setup of corrector magnets in operation to allow more precise control over tunes, chromaticities and resonance compensation. 

Subjects: 	Accelerator Physics (physics.acc-ph)
Cite as: 	arXiv:2301.04914 [physics.acc-ph]