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New BDS Production Deck -- BDS9801. PT, 26-October-1998. “Path that ever Promise made Desire dream dissolve and fade”. 1. Magnet Revisions. Why Revise any of the Magnets?. Vacuum: Magnet bore > 8 mm Transitions: mixed 1.2cm/1.0cm quad bores risky Uniformity of Quad Apertures.
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New BDS Production Deck -- BDS9801 PT, 26-October-1998 “Path that ever Promise made Desire dream dissolve and fade”
1. Magnet Revisions Why Revise any of the Magnets? • Vacuum: Magnet bore > 8 mm • Transitions: mixed 1.2cm/1.0cm quad bores risky • Uniformity of Quad Apertures
Changed quads/sexts to minimum 1.2 cm full bore: • 40 quads with Bpole > 6.7 kG (20 in final focus, 3 cm full bore) • 6 quads with Bpole 10-11 kG, all in pre-collimation diagnositcs • Bends need no revision • Sexts: 2 with Bpole > 7 kG -- longer?
2. IP Switch/Separator • IP separation: > 200 m in z • One beamline (“Short BDS”) bends at IPSW, other goes straight to second IPSW module • IPSW = 100 m, so need 100-200 m Separator beamline
Design Constraints of IP Separator Design • Both beamlines pass through IP Switch # 1 -- for IP 2, bends are turned off + Degaussed! • IP 2 line should contain second IP Switch for energy diagnostics • Dfx,y = np between 2 lines (collimation)
IP Separator Solution • Both beamlines pass through IPSW1 • IPSW quad + 2 post-IPSW quads common (move ~ cm’s) • “Long BDS” contains 5 new quads, 2nd IP SW + 2nd match into Big Bend
IP Separator Soln (contd) • Total added phase advance = 2p in x and y, Dz = 287 meters • A few quads and bends in short BDS must be moved out of way • Optically solution is marginal: (Dsx,Dsy) = (0.5%,2%) --chromaticity?
Conclusions: (good news) • New BDS Deck (BDS9801) almost ready for release • Quad bores expanded • IP Separator Beamline included
Conclusions (bad news) • Many quads too strong for 1.5 TeV CM; some bad for 1 TeV • IP separator design requires several shifts for IP switchover • Separator chromaticity requires IPSW/BB sexts (needed anyway)
Conclusions (ugly news) • Need revised collimation region (no passive survival) • Need IPSW/BB sextupoles • Need to try longer, weaker IR quads