Guy Wormser, Super B-Factory Workshop, Jan 04 1 BELLE/BABAR present background situation zThe information from BELLE: es.html zMost important talks: ySummary from Haba-san, y Current Belle background from Tajima-san zAlso some informal inputs

Guy Wormser, Super B-Factory Workshop, Jan 04 2 BELLE Background general features zCoasting backgrounds yOverall smaller background level y« SVT » background perfectly described by the sum of SR, beam gas and Touschek yStrong Touschek effect seen in the DCH yTOF (+50%) and Muon (x5) see larger bkg in collision than sum of single beams zInjection backgrounds: not a problem ! zBurst events: Happen one every few hours, last ~1 sec, spontaneously digested zTrips: a few per day

Guy Wormser, Super B-Factory Workshop, Jan 04 3 SVD Upgrade in 2003 summer r bp = 2.0 cm 3 layers Rad. hardness r bp = 1.5 cm 4 layers > 10 MRad (DSSD) > 20 MRad ( readout chip ) ~ 1 MRad  Better vertex resolution / tracking efficiency

Guy Wormser, Super B-Factory Workshop, Jan 04 4 Other sub-detectors No large difference for BG (current diff. causes small diff. ?) No problem SVD 1.6 (Jun, 2003) SVD 2.0 (Dec, 2003) beampipe radius2.0 cm1.5 cm HER/LER1.0 / 1.5 A1.1 / 1.6 A CDC leak current 19  A21  A TOF rate20 kHz25 kHz EFC rate2.1 kHz2.2 kHz

Guy Wormser, Super B-Factory Workshop, Jan % occupancy means 10k ch has unnecessary hits!

Guy Wormser, Super B-Factory Workshop, Jan 04 6 Extraction SR in HER Single Beam 50 mA 100 mA 200 mA 400 mA600 mA800 mA HER Particle SR Hard-SR simulation Cool work! O. Tajima

Guy Wormser, Super B-Factory Workshop, Jan 04 7 translated differently as Unbelievable ! (Karim) I don’t believe it (Steve, O)

Guy Wormser, Super B-Factory Workshop, Jan 04 8 Study of Touschek Effect Touschek contribution < 20 % at collision ~ 50 % at single beam 31 % in simulation Smaller beam-size (larger density)  larger background If no Touschek Touschek contribution must be corrected Collision run Single beam run O. Tajima What we learn here is beam is different for collision.

Guy Wormser, Super B-Factory Workshop, Jan 04 9 Towards a quantitative comparison zSome numbers available but direct detailed quantitative comparison with BABAR is not yet possible!! zBELLE figures of merit yIntegrated dose in Calorimeter 100 Rad yDose rate in SVT layer1, not very much phi dependant 100 krad yIntegrated dose in all their SVTs 1M Rad yCurrent drawn from their chamber 1 mA zSeems certainly more confortable than here but by how much?How to compare: zBELLE_SVT first layer: Occupancy 10% but long shaping time (800ns) Dose: remove injection, radius different, different lengths,… DCH different volume, gas gain EMC remove injection, check theta dependencies,etc…

Guy Wormser, Super B-Factory Workshop, Jan Comparison templates (1) z System SVT Layer 1 zSensor used: Occupancy zStrip width, lenght, radius, integrating time z Parametrization as fct of HER (2nd degree polynomial), LER (idem) for single beams zPlot of [observed – sum singles] vs lumi zIntegrated dose as function of integrated lumi for running zintegrated dose during injection zRatio of max/min as function of Phi zAverage Trip rate per day from the SVT protection system zBias On/off during injection?

Guy Wormser, Super B-Factory Workshop, Jan Comparison template (2) zSystem DCH zSensor : Total current draw zGain, volume, min-max radius,length zParametrisation as function of single beams (second order poly) zPlot of (observed –sum of single beams) as function of lumi z Integrated dose per wire in C/cm zAverage spikes due to dust event per day; average trip per day zSignal any strong azimutal of z dependance

Guy Wormser, Super B-Factory Workshop, Jan Touschek effect at PEP-II

Guy Wormser, Super B-Factory Workshop, Jan Sensor BLLC2081 as fct of HER and LER

Guy Wormser, Super B-Factory Workshop, Jan Beam and beam and Touschek SensorHERLERLumiBBTouschek PR Q PR Q Q Q-30Q Q Q L-20Q L-40L Q L7L L-7L X Q-200L L Q10X Q PR L

Guy Wormser, Super B-Factory Workshop, Jan BLSC 3072

Guy Wormser, Super B-Factory Workshop, Jan vs HER

Guy Wormser, Super B-Factory Workshop, Jan Comparison template (3) zSystem EMC zSensor : Number of clusters above 1 MeV (or mean energy per cluster?) zRadius, crystal size, shaping time, amount of X0 in front zSingle beam parametrization (second order polynomials) for Her and LER zObserved –(sum of singles) as function of Lumi zIntegrated dose Maps as function of Tetha; as function of integrated lumi zAny azimutal effect?

Guy Wormser, Super B-Factory Workshop, Jan Extrapolations for SUPERKEK and Super PEP zTHe IR design is key to the background level zThe consensus IP looks like the present KEKB but with more magnetic field and closer to detector: the sensitivity to rad Bhabbas will increase compared to present KEK zSuperK rule of thumb: x20 all present background z Not so conservative in my mind because the present KEKB background is well described by just the sum of SR, BeamGas and Touschek but I have strong doubts this will be the complete list at 10**35 zOn teh other hand, it makes no sense to extrapolate present PEP-II numbers x100 since the Super IR should be more background friendly than the present one.

Guy Wormser, Super B-Factory Workshop, Jan Conclusions zKEKB background situation is certainly better than ours. This is due to the absence of sweeping fields very close to the IP zA detailed comparison is not yet possible but is very desirable. I would like an agreement/comments on the proposed templates, and send them to KEK while we fill them zKEKB is able to describe their inner background by a sum of only three terms: SR, Beam Gas and Touschek zWe need to make an effort to quantify our SR and Touschek contributions. zThe neutron rate outside of the detector is another critical element (they have a very large collision term in the muon system, although the overall rate is low)