LSS1 post LS2 F.M. Velotti, B. Goddard

Q-Dogleg in LSS1 The quadrupole misalignment in LSS1 was needed to dump horizontally wide beams (e.g. FT beam at 400 GeV) onto the TIDVG One of the quadrupole (QDA.119) of the dogleg is just upstream the injection kicker MKP The QDA.119 misalignment helps the injection of high energy beams, like LHC beam The suppression of the dogleg can be compensated with small MKP variation on the FT orbit (and MSI) and with MSI+TL steering for the LHC orbit

Q-Dogleg in LSS1 For the FT beam, a small adjustment of the MSI strengths (i.e. Δθ = 40.6 μrad per MSI) and 0.9 kV more for the MKP (V = 49.9 kV) are needed

Q-Dogleg in LSS1 For the LHC beam, a small adjustment of the MSI strengths (i.e. Δθ = 20.6 μrad per MSI) and steering with one of the TT10 corrector/bend (MDLH => θ = -46 μrad) are needed

Enlarged Quadrupoles in LSS1 Four quads in LSS1 are the enlarged type: QFA.116/8 and QDA.117/9 The QFA.116 is the first focusing quad after the TIDP (momentum collimator and horizontal aperture bottleneck of the SPS) => studies regarding the optimisation of the TIDP are on going, hence they should also evaluate if the enlarge aperture is needed

Enlarged Quadrupoles in LSS1 Four quads in LSS1 are the enlarged type: QFA.116/8 and QDA.117/9 The QDA.117 doesn't seem to have any specific reason to be there - maybe for symmetry wrt the QFA.118 and QDA.119 for the dogleg

Enlarged Quadrupoles in LSS1 Four quads in LSS1 are the enlarged type: QFA.116/8 and QDA.117/9 The QFA.118 is a key element for the dump system => not needed anymore in LSS1 for the dump…obviously! The SPS scrapers are just upstream this element => to be checked if needed or not for it

Enlarged Quadrupoles in LSS1 Four quads in LSS1 are the enlarged type: QFA.116/8 and QDA.117/9 Only the QDA.119 is needed to host injected beam

Injected beam envelope QDA.119QFA.118 Injection channel

Injected beam envelope Keep DN350-DN273-between QFA.118 and QDA.119

aperture - draft DN350 DN273 DN165

Conclusions The removal of the quad dog-leg in LSS1 clearly changes the injection trajectory, hence the injection elements have to be modified accordingly For the FT beam, a trim of the MSI and MKP (< 1 kV) should be enough. For the LHC beam, a "steering" of TT10 and trim of MSI should also be enough to inject on the nominal CO Regarding the enlarged quads in LSS1: The aperture of the QFA.116 should be evaluated in the context of the studies regarding the optimisation of the TIDP, otherwise there is no obvious reason to retain it. There is no obvious reasons to retain an enlarged quadrupole in 117 The QFA.118, with displacement of the SBDS, will not be needed anymore => to be checked what will be the effect on beam losses having the scraper before a normal aperture quad The QDA.119 is needed for the injected beam trajectory Scattered particles from scrapers and momentum collimators should also be considered for the choice of the vacuum chambers Between the QFA.118 and QDA.119 the enlarged VC is needed to host the injected FT beam