Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 1 Status on an IR Design for a Super-B Factory M. Sullivan for the Super-B Factory Workshop Hawaii April 20-23, 2005

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 2 Outline General B-factory parameters IR parameters Synchrotron Radiation Issues Present IR design Summary and conclusions

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 3 PEP-III Super B parameters for a 1  Luminosity Super B LER energy 3.5 GeV HER energy 8.0 GeV LER current 23.0 A HER current 10.1 A  y * 1.5 mm  x * 15 cm X emittance 40 nm-rad Estimated  y * 1.7  m Bunch spacing m Number of bunches 6900 Collision angle  14 mrads Beam pipe radius 2.5 cm Luminosity 1  cm  sec 

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 4  Detector acceptance down to 300 mrad angle – forward and backward  Beam pipe radius of 2.5 cm  Translates to ±10 cm of active beam pipe  The Q2 septum is at 2.5 m IR design parameters

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 5  PEP-II IR design ended up with ~10  /crossing – which is 2.39 Ghz – rate on the detector beam pipe (11 krad/yr)  Background levels from SR can be no more than factor of 100 to 1000 times higher than PEP-II before radiation doses get too high (occupancy may be OK for pixelated detector)  Make all of the SR radiation from local bends in the beam miss nearby surfaces (power from the high current beams is too high for local absorption) SR constraints and limits…

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 6 Current baseline design

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 7

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 8 Version  /X  /sWatts PEP-II design102.39e91.4e-511 krad/yr Baseline design HER4.65e44.37e LER5.71e45.37e Offset Q4 10 mm & offset Q2 12 mm HER e113.1e-4 LER e111.1e-3 8  instead of 10  HER e112.8e-4 Tail #1 HER e91.3e-5 LER e94.2e-5 Tail#2 HER e72.2e-7 LER e86.8e-7 No tails HER6.9e e-51.5e-19 LER1.3e e-17 SR backgrounds photons > 4keV on the physics window beampipe

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 9 Vertical plane is not as hard Horizontal plane is more difficult so try to steer the Q5 radiation away from the beam pipe

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 10

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 11 Bending power vs quadrupole power Magnet Bending pwr Quadrupole pwr HER beam (10A) Up Q W Up Q W~3000 W LER beam (23 A) Up Q23433 W46 W

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 12 What is the correct beam tail distribution? The present PEP-II design is insensitive to the tail distribution since the SR background is dominated by local bending fans. This allowed us to assume a conservative (high) tail particle density The PEP SuperB design minimizes local beam bending and hence the beam tail distribution becomes more important Note: the background from SR comes only from the x plane

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 13

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 14 We have made progress on a PEP SuperB interaction region design with a luminosity of 1  Synchrotron radiation backgrounds look managable. Much more work needs to be done…. Minimal beam bending leads to a design that is sensitive to the beam tail distributions, … Perhaps we can learn more about the correct beam tail distributions from the present B factories. Summary and Conclusions

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 15 Backup slides

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 16

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 17

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 18

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 19

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 20 KEKB Upgrade Plans Now Upgrades SuperKEKB LER energy GeV HER energy GeV LER current A HER current A  y * mm  x * cm X emittance nm-rad Estimated  y *  m Bunch spacing m Number of bunches Collision angle  11 crab  15 (crab)mrads Beam pipe radius cm Luminosity 1.06    cm  sec 

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 21

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 22

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 23

Super-B Factory Workshop April 20-23, 2005 Super-B IR design M. Sullivan 24