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Bunch Train studies

Bunch Train studies. Niels van Eldik, Peter Kluit, Siyuan Sun Simulation meeting PP 22 April 2013. Data sets. Run with a few bunch trains in 2011: data11_7TeV.00180309.physics_MinBias.recon.ESD.r2603 Zero bias run: data12_8TeV.00202740.physics_ZeroBias.merge.ESD.r4065_p1278/

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Bunch Train studies

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  1. Bunch Train studies Niels van Eldik, Peter Kluit, Siyuan Sun Simulation meeting PP 22 April 2013

  2. Data sets Run with a few bunch trains in 2011: data11_7TeV.00180309.physics_MinBias.recon.ESD.r2603 Zero bias run: data12_8TeV.00202740.physics_ZeroBias.merge.ESD.r4065_p1278/ The trigger is zero_bias. Technically it is the event one turn of the accelerator after L1_EM14 fires (to record events proportional to instantanuous lumi in each bunch).

  3. MDT cluster bunch trains

  4. MDT clusters Zero Bias

  5. MDT cluster position bunch trains

  6. MDT cluster position Zero bias Different shielding in 2012

  7. MDT Segment clusters bunch trains vs Zero Bias

  8. MDT Segment cluster position bunch trains vs Zero Bias

  9. MDT bunch structure

  10. RPC/TGC bunch structure

  11. Rate in the empty bunches Nr Bunches in the 9 bunch trains: 424 Rate = total in empty bunches / total in all bunches mdt singles mdt 2-3-4 0.0353371 0.0205156 EI segment cluster EM segment cluster EO segment cluster 0.00731837 0.00582517 0.00671376 rpc singles rpc doublets tgc singles tgc doub-triplets 0.0447499 0.0128788 0.0216502 0.0110569 If we call Cavern background that which is present in the empty bunches, It would mean for a filled machine with 1600 bunches we have to multiply this with ~4 to obtain the cavern background in a filled machine MDT singles 15%; 2-3-4 8%; segments 3% RPC doublers 5%; TGC doub-triplets 4%

  12. Trigger bias in Min bias sample? For this we analyzed the ZeroBias data. Here the primary trigger is the L1_EM14 trigger and then the BC is read out after one LHC turn. This data has NO trigger bias; but it will only read out filled bunches. The empty bunches will not be readout because the EM trigger not have fired. Selecting the same lumi block the number of MDT single hits per event is determined to be: Min Bias: 203 Zero Bias: 213 This implies that there is no trigger “enhancement” or “bias” in the filled bunches in the Min Bias stream. Zero bias MDT singles

  13. Conclusions Distributions for the bunch train 2011 data set for MDT cluster multiplicities and position are comparable to the 2012 ZeroBias data. The effect of the new shielding installed in 2012 is observed. If we call Cavern background that which is present in the empty bunches. MDT singles 15%; 2-3-4 8%; segments 3% RPC doublers 5%; TGC doub-triplets 4% Most of the background is the in- and out of time Minimum bias pile up background.

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