L4 transfer line to the PSB

L4 transfer line to the PSB update from Oct 20101LINAC4 BCC -1 septembre 2011Christian Carli, Margarita Garcia Tudela Alessandra Lombardi Lutz Hein, Mohammad EshraqiLINAC4 transfer line optics

M. Eshraqi, L. Hein, A. Lombardi (BE-ABP)LINAC4 transfer lines : 177.31 m (from PIMS out to foil); 69.83 m new line,then join at BHZ20 the present Linac2 line (107.48 meters from BHZ20 to foil). Active elements : 4+2bendings;16+18 quads,11+11 steerers and 1 RF cavity. Optics LayoutTunabilitySafety margins

L2PSBL4

2.5m14 OCTOBRE-2010Active elements : 5+2bendings;17+18 quads,13+11 steerers and 1 RF cavity. Main changesHorizontal bending : 70 degrees from the Linac4 into the connecting tunnel are done with 3 bendings instead of 2 . Motivation : use short(er) H bends.

Vertical step : 2.5 meters between Linac4 and PBS are done on a 15 degrees slope instead of 28 degrees. Motivation : decrease the gradient in the quadrupoles. LINAC4 BCC -1 septembre 20113Top View proposed layout4

BCT as far upstream as possible (reference value)BCT (not too) closeto exit of bendBCTs close (not too) toentrance and exit of bend(losses in vertical step)Profile monitor(beam size critical at entrance in vertical step)BCT somewhere before debuncherProfile monitor(momentum spread measurement withSpecial quad setting)C. Carli

3 horizontal bends layoutBHZ.205Proposed Layout 8.2m10 m3 horizontal magnetsAngle = 70/3 = 23.33 degL= 4.1m (from deflection point to the next bending dp)Lmag= 870 mmLarc= 876mm = 2151.15 mm

Vertical stepAchromatic translating system. Need to have 2 phase advance at zero currentThe longer the distance between the two vertical bendings the stronger the integrated quadrupole gradient.

LINAC4 BCC -1 septembre 20116

5 m between bendings28 degrees slope4 Tesla integrated field in the quads10 m between bendings 15 degrees slope 1.8 T integrated field in the quadsBeam dynamics (Up to BHZ.30)7

Beam dynamics (Up to BHZ.30)8

Beam dynamics (Up to BHZ.30)9

ConclusionBeam dynamics has been recalculated after adapting the layout to the bending and quads design.nominal beam quality, flexibility and sensitivity are unchanged seen from the PBS.Needs to be verified Steering sensitivity with new layout and vacuum chamber Detail the commissioning strategy and dispersion control

LINAC4 BCC -1 septembre 201110Appendix Straight lineReduced distance bending towards the tunnel to the dump entailed a redesign of the emittance measurement line before the dump.Make use of the forward method reconstruction : improved accuracy on the evaluation of emittance from profile measurements in presence of space charge

LINAC4 BCC -1 septembre 201111Emittance estimation in L4ZHardware: 3 semgrids. No extra quads!Minimum rms beam size is +- 1 mm -> Resolution 0.3-0.5 mm.Location of the semgrids:- just after quadrupole L4T.MQF.0210just before L4T.MBH.0250 . 2 meters after the L4T.MBH.0250

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