IR Summary M. Sullivan For M. Boscolo, K. Bertsche, E. Paoloni, S. Bettoni, F. Bosi, P. Fabbricatore, S. Farinon, N. Carmignani, P. Raimondi, M. Biagini, P. Vobly, I. Okunev, A. Novokhatski, S. Weathersby, R. Cenci, A. Perez, et al. SuperB General Meeting XVII La Biodola, Isola d’Elba, Italy May 28 - June 2, 2011

Outline Current IR design Beam backgrounds QD0 (and QF1) Vibration budget and control MDI issues (in case Eugenio missed something) and the next steps in the design Summary

Present Parameters (V12 lattice)

Parameters used in the IR designs Parameter HER LER Energy (GeV) 6.70 4.18 Current (A) 1.89 2.45 Beta X* (mm 26 32 Beta Y* (mm 0.253 0.205 Emittance X (nm-rad) 2.00 2.46 Emittance Y (pm-rad) 5.0 6.15 Sigma X (m) 7.21 8.87 Sigma Y (nm) 36 36 Crossing angle (mrad) +/- 30

General IR Design Features Crossing angle is +/- 30 mrads Cryostat has a complete warm bore Both QD0 and QF1 are super-conducting PM in front of QD0 Soft upstream bend magnets Further reduces SR power in IP area BSC to 30 in X and 100 in Y (7 fully coupled) SR scanned to 20 in X and 45 in Y

Air-Core “Italian” Design The shared QD0 and QF1 parts of the VP design are the air-core design The QD0 and QF1 are parallel to the detector axis Then we have the same field strengths and the LER and HER pieces are the same strength as the VP design

Air core “Italian” QD0, QF1

SR backgrounds No photons strike the physics window We trace the beam out to 20 X and 45 Y The physics window is defined as +/-4 cm for a 1 cm radius beam pipe Photons from particles at high beam sigmas presently strike 7-10 cm downstream of the IP However, the highest rate on the detector beam pipe comes from points that are a little farther away This is true for both the vanadium permendur and the air-core design

Beam Backgrounds Manuela Boscolo gave us an update on beam related backgrounds BGB Touschek Coulomb She mentioned that radiative Bhabhas and 2 photon e+e- production are the primary luminosity backgrounds In summary the backgrounds are under control

Collimator settings are about 25-35 

Radiative Bhabhas We had a presentation on backgrounds from radiative bhabhas from Alejandro Perez A great deal of work has gone into simulating the beam line components Magnetic fields but not yet material Some “hot spots” have been identified and more work is needed to see how these might be reduced

Current IR Analysis Status SR backgrounds are under control However need to extend the SR beam scan out to at least 25 and check that the high sigma particle density is high enough SR power inside the cryostats looks manageable Also preliminary look at SR energy penetration Beam-gas, Touschek and Coulomb backgrounds are under control Collimator location ranges are about 25-35 Beta functions are reasonable Vibration control has been studied Preliminary designs for solenoid compensation completed Magnetic fields (Bertsche) Lattice corrections (Nosochkov)

QD0 Work is continuing toward building a prototype QD0 magnet (Eugenio’s talk) Pasquale Fabbricatore and Stefania Farinon from Genoa are helping us design real magnets and cryostats This is a major step forward. The design needs to be shaken down with just this type of work.

E. Paoloni

QD0 Field simulation We had a very interesting presentation on the modeling of the QD0 field by Nicola Carmignani This is a sophisticated simulation and will be very useful for developing more detailed dynamic aperture studies and the effect of the final focus elements on the dynamic aperture From Nicola’s presentation

From Nicola’s presentation Bz By Bx

Vibration Control for the FF and Measurements of the Tor Vergata Site Ground Motion We had two very nice presentations on vibration control and measurements Kirk Bertsche showed further analysis of the FF vibrations Laurent Brunetti showed new data on ground motion measurements at Tor Vergata (John’s talk)

Vibration control for the FF Kirk Bertsche refined his analysis of the vibration issues for the final focus magnets and what we need to achieve in motion control to keep the beams in collision – he now includes tolerances for the rest of the ring One primary conclusion is that the Tor Vergata site is better than the Frascati site for vibration control at the IP In addition, it has occurred to him that the source points for the synchrotron people may turn out to have the most stringent stability requirements – this should be checked

MDI and IR issues Cryostat size W shielding Rapid access Vibration control Cryostat supports SVT supports SVT services and signals These are all inter-related as general MDI issues

IR Permanent magnet design details QD0 and QF1 design details QD0H and QF1H Panofsky style design details Anti-solenoid design details Vacuum cooling, BPMs and assembly

Summary We have a design that is flexible and has good: SR backgrounds Beam backgrounds Lattice functions Beam apertures The design options are: Vanadium Permendur for QD0 and QF1 Parallel air-core dual quads for QD0 and QF1 Both designs include additional vanadium permendur Panofsky quads on the HER

Summary (2) The IR design demonstrates robustness We have two separate QD0 designs The direction of the beams can be either way with a weak preference for the incoming beams to be from the outside rings due to the location of the SR power on the cryostat beam pipe The design has good beam energy flexibility Tau-charm threshold should be rechecked Different boost values

Summary (3) Good progress is being made on the design of the QD0 A prototype of the air-core design is being built This will test the feasibility of the air-core design Design details are encouraging a redesign of the IR – trying to maintain our overall parameter set An overall vibration control design is being developed for the FF magnets. The measurements of the Tor Vergata site are very encouraging and the fact that the beams tend to move together with QD0 motion has significantly loosened the vibration tolerance requirements on cryostat motion

Conclusions The IR design is now getting feedback from design details As engineering concerns are uncovered we will have to make modifications to the design but I believe this design has the room and robustness to respond to these demands