M. WeaverPEP-II MAC Review,15-17 Nov’07  Operational issues  radiation aborts  background monitoring  Background extrapolations  model comparisons to performance  simulations  vulnerabilities  IP characterization measurements Machine-Detector Interface (MDI) report Presented by M. Weaver, SLAC

M. WeaverPEP-II MAC Review,15-17 Nov’07 Run-6 radiation-abort history B. Petersen S. Curry ~ 2.8/day Jan 2007 May 2007 Sep 2007 Jul 2007 Mar 2007

M. WeaverPEP-II MAC Review,15-17 Nov’07 Forward West Forward East Backward West Backward East Abort-by-dose location HER vacuum events Jan 2007 May 2007 Sep 2007 Jul 2007 Mar 2007 Jan 2007 May 2007 Sep 2007 Jul 2007 Mar 2007

M. WeaverPEP-II MAC Review,15-17 Nov’07 Background Monitoring Summary  SVTRAD diodes + diamondsdose rates, dose / injection  DCH high voltagecurrent  DRC PMTsscaler rates  IFR high voltagecurrent  Fast Control & Timingdeadtime, L1 rates, time wrt injection  Level 3 Triggersubdetector occupancies  Neutron counters scaler rates  CsI IP detectors(logarithmic response)  All update in small intervals (1-5 seconds)

M. WeaverPEP-II MAC Review,15-17 Nov’07 Run-6 radiation-dose rates Dose rate (mrad/s) Pressure (nT) Incoming HER Vacuum BW Diamond BE Diamond Incoming LER Vacuum

M. WeaverPEP-II MAC Review,15-17 Nov’07 Injection- & trickle- background history Monitor by integrating SVTRAD diode signals over 12 ms after each injection SVT electronics are sometimes “upset” by exposures greater than 50 mrad / injection. HER injection-quality monitor LER LER injection-quality monitor Average Dose/Injection (mrad)

M. WeaverPEP-II MAC Review,15-17 Nov’07 DIRC PMT Scaler Rate DIRC reconstruction has been shown to be robust up to 1MHz hit rate.

M. WeaverPEP-II MAC Review,15-17 Nov’07 Detector Occupancies (%) SVT Layer 1 East SVT Layer 1 West DCH Total EMC Total Tuned noise thresholds and tightened time windows

M. WeaverPEP-II MAC Review,15-17 Nov’07 Background sources in PEP-II  Beam-gas (bremsstrahlung + Coulomb)  HEB only: B Hbg ~ I H * (p H 0 + P H Dyn * I H ) Note: p 0 = f(T) !  LEB only: B Lbg ~ I L * (p L 0 + P L Dyn * I L ) Note: p 0 = f(T) !  beam-gas x- term: B LHbg ~ c LH * I L * I H (LEB+HEB, out of collision) (?)  Luminosity (radiative-Bhabha debris) – major concern as L   B P ~ d P * L (strictly linear with L)  Beam-beam tails  from LER tails: B L, bb ~ I L * f L (  L,H +/- )  from HER tails: B H, bb ~ I H * f H (  L,H +/- )  Trickle background: B Li, B Hi  Trickle background: B Li, B Hi (injected-beam quality/orbit + beam-beam)  Touschek: B LT  Touschek: B LT (signature somewhat similar to bremstrahlung; so far small) Still using characterization of Jan’04

M. WeaverPEP-II MAC Review,15-17 Nov’07 Projected DAQ Requirements/Performance Processing Time Fiber Transfer Feature Extraction Processing Time Threshold tuning and window tightening upgraded L1 Rate (Hz) Time 7.0kHz “ceiling” 5.8kHz average upgraded

M. WeaverPEP-II MAC Review,15-17 Nov’07 SVT Integrated dose will be more than 1 Mrad/year Backward: Forward: TopEastWestBottom TopEastWestBottom NOW Background will be 50% HER, 50% L Background strongly  - dependent Predict 80% chip occupancy right in MID-plane In layer 1, 10% will be above 20% occupancy Projected Detector Occupancies

M. WeaverPEP-II MAC Review,15-17 Nov’07 Background model comparisons (measured/model) Bwd East Dose Rate Bwd West Dose Rate Lots of vacuum work during pre- Run6 downtime resulted in a long time to scrub. HER vacuum performance still better than predictions from Jan’04 characterization. Ratio

M. WeaverPEP-II MAC Review,15-17 Nov’07 DCH BackgroundL1 Trigger Rate Background model comparisons (measured/model) Trigger rate somewhat larger than characterization. Results in higher deadtime. Run6 backgrounds still consistent with characterization.

M. WeaverPEP-II MAC Review,15-17 Nov’07 DRC Background Background model comparisons (measured/model) Large fluctuations but tolerable in this subdetector.

M. WeaverPEP-II MAC Review,15-17 Nov’07 Machine Background Simulations  Long effort to simulate sources of machine backgrounds to improve understanding  Added interest from future B-factory designers  Difficulty integrating tools  LER model was completed long ago and simulated with not- so-satisfactory results. Problems uncovered generating HER model. At long last, HER model is consistent among the tools. Ready to simulate and analyse.  Analysis may learn something in time to compare against machine operation but benefit is unknown. Accelerator Design (MAD) Primary Interactions (Turtle) Secondary Interactions + Detector Response (GEANT)

M. WeaverPEP-II MAC Review,15-17 Nov’07 Detector Vulnerabilities  Readout Deadtime  Inefficiencies, backgrounds (combinatorics)  Damage SVT Total DCH EMT Extrapolation (5.8kHz) x2 Background (7kHz) BaBar experts are estimating worst tolerable conditions A tightened “emergency” trigger configuration is ready, just in case…

M. WeaverPEP-II MAC Review,15-17 Nov’07 IP Characterization  Use BaBar’s tracking resolution and prime venue for measuring important parameters at the IP  Three analyses each measuring  y,  * y  dLumi / dz vertexing e + e - and  +  - events   yLumi (z)  +  - events   y’Lumi (z)  +  - events (resolution) Production vertices (x,y,z ~ 30  m) Boost trajectories (  ~ 0.6 mrad) e- beam e+ beam

M. WeaverPEP-II MAC Review,15-17 Nov’07 BaBar IP measurements reported online  Luminous Region  centroids { x, y, z}  sizes { x, z } every 10 minutes  tilts { dx/dz, dy/dz }  dL/dz fit {  z,  * y, z w, z c } every ~hour  Boost Trajectory  mean { x’, y’ } every 10 minutes  spread { x’ HER, y’ HER } every 30 minutes }

M. WeaverPEP-II MAC Review,15-17 Nov’07  V RF  z (mm) Bunch Length Extraction from d L /dz Fits BaBar Run  z 2 = 10.3 mm 2 ± 0.4 mm 2 zH , 10.9 mm 10.4 mm 10.8 mm ± 0.2 mm zL , ± 0.2 mm  y * = 13mm

M. WeaverPEP-II MAC Review,15-17 Nov’07 d L /dz IP Beta Function Measurements yLyL  y’ B PEP phase advance  2

M. WeaverPEP-II MAC Review,15-17 Nov’07 Summary (I)  Expect a painful scrubbing process at the beginning of Run7. Lots of HER arc vacuum work done to remedy source of abort-inducing vacuum events.  Injection backgrounds sometimes problematic but generally under-control  Stored-beam bgds (dose rate, data quality, dead time)  Some differences from run5 but similar magnitude.  No new thermal outgassing/vacuum activity near the detector.  Background characterization  No new experiments. Too late in the game to repeat, no time for hardware interventions.  Latest measures of the projected backgrounds still look good.  Uncertain about beam-beam backgrounds – Run5 experiment suggested not so large, Run6 experience somewhat different.

M. WeaverPEP-II MAC Review,15-17 Nov’07 Summary (II)  Simulation  After a long struggle, ready to analyze HER backgrounds.  BaBar-based IP characterization  Incorporating effects of coupling  Working on including X-ray and SL beam profile monitors

M. WeaverPEP-II MAC Review,15-17 Nov’07 Spare Slides