1. W. KozaneckiIR summary, BES-III workshop Interaction Region: a terse summary  Accelerator issues  Parameter comparison with PEP-II/KEKB  IR layout  Particle-loss mechanisms  Thermal issues  Detector issues  Machine background predictions  Detector radiation-protection & beam-abort  Luminosity monitor  Subdetector-specific issues (DCH, trigger, TOF)  Summary: the most critical/urgent studies Conveners: K. Trabelsi, W. Kozanecki A very lively & productive interchange between BEPC & BES experts!

2. W. KozaneckiIR summary, BES-III workshop  Introduction  Experience in PEP-II & BaBar: Iimportance of an integrated approach to –Solving layout problems –Predicting (now) & understanding (later) machine backgrounds –IR heating issues (SR, HOM) –Machine operation (injection, abort,...)  Accelerator issues  Parameter comparison: BEPCII vs B-factories  Same beam-current & L regime  The joys & the pains of 2-ring machines  Some issues harder, a few easier  IR layout  orbits, BSCs, aperture constraints, … T: Xu Gang Major implications for machine + SR backgrounds T: WK

3. W. KozaneckiIR summary, BES-III workshop  Accelerator issues (ct’d)  IR layout (cont’d)  Mechanical & vacuum interfaces Significant enginering “challenge” in accomodating necessary mechanical/vacuum interfaces in the heart of BESIII T: HUANG Nan

4. W. KozaneckiIR summary, BES-III workshop  Accelerator issues (ct’d)  IR layout (cont’d)  Mechanical & vacuum interfaces “support tube” approach (BaBar) impractical bec. of DCH conical shape

5. W. KozaneckiIR summary, BES-III workshop  Accelerator issues (ct’d)  Particle-loss mechanisms  Injection Injected e - : prob. OK Injected e + :  inj/stored ~10 ==> x-baam size x 3-4, ==> (present) clearance ~ 1  injected –If confirmed,  !! –Need better understanding of injected beam specs (A+D) –may need to collimate (“shave off”) tails in linac, before injection  Beam abort: gap needed  Touscheck: need background calculation (A+D; Turtle!)  Beam-beam brems (aka radiative Bhabhas): where do the debris go? (Turtle!)  Need iterative vacuum calculations (bgd! A+D) Ring circumference I bunch Gap size driven by kicker rise time

6. W. KozaneckiIR summary, BES-III workshop  Accelerator issues (ct’d)  Thermal issues: IR very sensitive  Synchrotron radiation  HOM losses BaBar luminosity presently limited by heating here

7. W. KozaneckiIR summary, BES-III workshop  Detector issues  Machine background predictions  Radiation tolerance of BES subdetectors Most sensitive to injection: calorimeter Most sensitive to stored beam: DCH Numbers & criteria/specs needed!  Occupancy issues in BES subdetectors (esp. trigger) Numbers & criteria/specs needed!  Background simulations Belle experience Early BES beam-gas & SR studies T: K. Trabelsi T:Jin Dapeng

8. W. KozaneckiIR summary, BES-III workshop Detector issues (ct ’d) Machine background predictions (ct ’d) Background simulations (ct ’d) Early BES beam-gas & SR studies T:Jin Dapeng Total power Total photon flux

9. W. KozaneckiIR summary, BES-III workshop  Detector issues (ct ’d)  Detector radiation-protection & beam-abort: consensus it is absolutely needed SVT abort diode Chronic dose trip level 1M trigger rate

10. W. KozaneckiIR summary, BES-III workshop  Detector issues (ct ’d)  Luminosity monitor  Absolute: large- and/or medium angle BhaBhas  Relative: 0°-BhaBhas (e + e -  ) Water Cerenkov referred (Belle), 1/side essential for –Machine optimization –Beam-beam centering (feedback) –b-b vertical (y-z) alignment –IP beam size measurements –Bunch train diagnostics  Machine vs detector operation  Trigger: must accommodate easily arbitrary bunch patterns  TOF: consider separate timing signal from trigger (phase drift along train)  DCH: turn HV off/on afap Luminosity by bunch (HER) beam blow- up

11. W. KozaneckiIR summary, BES-III workshop Summary: the top of the list….  IR layout : trade-offs between  Orbits  Backgrounds  Engineering  Injection !!  Abort gap => kicker R&D  Background simulations  SR  Beam-gas  Touscheck