Challenges, Field Tuning Strategies, and Results for the Magnetic Qualification of Triplet Magnets for the SLS 2.0 Upgrade

This paper presents the measurement results obtained from the Triplet magnets assemblies for the Swiss Light Source (SLS) 2.0 upgrade [1]. Emphasis is given to the measurement challenges related to the tuning process of those magnets guaranteeing the production quality. The complete renewal of the SLS storage ring (SLS 2.0) leverages on the use of a longitudinal gradient bend (LGB) function. This is implemented by a Triplet, a crucial component of the new seven-bend achromatic lattice. The precise tuning of the integral LGB function, with a relative uncertainty of 0.2% from the nominal design value, imposes demanding requirements in terms of measurement precision, mechanical alignment and time constrains. No harmonics optimization of a Triplet is envisaged, field quality relies on the accurate machining of the magnets' yokes.