Paper 
Title 
Page 
THPMR038 
NonLinear Errors in the Experimental Insertions of the LHC 
3472 

 E.H. Maclean, F.S. Carlier, M. Giovannozzi, A. Langner, S. Mönig, T. Persson, P.K. Skowroński, R. Tomás
CERN, Geneva, Switzerland



Correction of nonlinear magnetic errors in lowβ insertions can be of critical significance for the operation of a collider. This is expected to be of particular relevance to LHC Run II and the HLLHC upgrade, as well as to future colliders such as the FCC. Current correction strategies for these accelerators have assumed it will be possible to calculate optimized local corrections through the insertions using a magnetic model of the errors. To test this assumption the nonlinear errors in the LHC experimental insertions have been examined via feeddown and amplitude detuning. It will be shown that while in some cases the magnetic measurements provide a sufficient description of the errors, in others large discrepancies exist which will require beambased correction techniques.


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※ DOI:10.18429/JACoWIPAC2016THPMR038


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THPMR044 
Short Term Dynamic Aperture with AC Dipoles 
3496 

 S. Mönig, J.M. Coello de Portugal, A. Langner, E.H. Maclean, T. Persson, R. Tomás
CERN, Geneva, Switzerland



The dynamic aperture of an accelerator is determined by its nonlinear components and errors. Control of the dynamic aperture is important for a good understanding and operation of the accelerator. The AC dipole, installed in the LHC for the diagnostic of linear and nonlinear optics, could serve as a tool for the determination of the dynamic aperture. However, since the AC dipole itself modifies the nonlinear dynamics, the dynamic aperture with and without AC dipole are expected to differ. This paper will report the results of studies of the effect of the AC dipole on the dynamic aperture.


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※ DOI:10.18429/JACoWIPAC2016THPMR044


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