NSW background modeling: hits and segment Injection

1. NSW backgroundmodeling: hits and segment Injection Niels van Eldik, Peter Kluit, Felix Rauscher PP 20 May 2013, see also: Muon NSW 12 May 2013

2. Introduction • Method: use the injection of hits segments in the Inner wheel for the estimation of the background • This is done in three steps: • 1) Validate and parametrize the hits and segments MDTs and TGCs in the Inner wheel using the high mu single bunch run. No out of time pile up is present here. Sim hits are produced and run though the standard digitization and analyzed. • 2) Apply time wrapping +- 40 BCs to these hits and segments and compare this to the backgrounds in the Z mumu period D data. This is a crucial test of the injection method. Note that the Z data doesnot only contain pile up but also cavern background. • New is the addition of Mdt clusters with large time smearing • 3) Simulate these hits and segments in the NSW detectors using a 25 nsec bunch spacing. The generated Sim hits are run through the fast digitization for the NSW detectors and analyzed.

3. Cross checks step 1TGC clusters Multiplicities are only quoted for the current BC Note the target for Data/MC is 0.5 Because only 1 endcap is simulated In step 2 the TGC will increased by a factor of 3

4. Cross checks step 1MDT clusters / TGC confirmed MDT multiplicities are only for inTime MDT hits (so within 0-700 ns drift time) In step 2 the TGC will increased by a factor of 3

5. Cross checks step 1MDT segment clusters Conclusions: reasonable description of the in time pile up in the MDTs and TGCs both for high and low cluster multiplicities. A more quantitative statement will be given at the next step.

6. Cross checks step IITGC clusters Here time wrapping +- 40 BC is applied and the “SimInjection” data is compared to the Z data that includes pile up and cavern background. Mdt clusters with large time smearing are added to take into account the cavern background. Note the target for Data/MC is 1 Both endcaps are simulated Average TGC rate is 0.64

7. Cross checks step 1IMDT clusters Rate of MDT clusters now OK scale factor 0.94 In previous extrapolation this was rather low. Due to addition of clusters with large time smearing.

8. Cross checks step 1IMDT segment clusters Average cluster segment rate is too high by a factor: 1.4

9. Conclusions from step 1-2 • The injection method: works reasonably • The step 2 test – with the addition of clusters with large time smearing the shows that: • TGC injected clusters are OK at the 35% level • MDT injected segments rates are OK at the 40% level • MDT clusters rate is OK within 5%

10. NSW backgroundmodeling: Simulations Pile up vs Injection Nektarios Benekos, Niels van Eldik, Peter Kluit, Felix Rauscher See also: Muon NSW 12 May 2013

11. Introduction • The results of two NSW simulations will be compared. • Full pile up simulation chain with new NSW detectors and fast digitisation. The sample was generated by Nektarios: sLHC, pileups ~120 to 140 with 25ns bunch spacing • /eos/atlas/user/n/nectar/NSW/PileUpProduction_sLHC/MC12.107209.ParticleGenerator_dimu_Pt10_100.atlasG4.0001/ • See also: https://indico.cern.ch/getFile.py/access?contribId=7&resId=0&materialId=slides&confId=248974 • This corresponds – my calculation - to a luminosity of 3e34 cm-2s-1. • In the plots sample 1) is scaled to a luminosity of 5.4e34 cm-2s-1.

12. Introduction • The second sample is: • The hit and segment Injection method. Background hits and segments are added in the Inner wheel using a 25 nsec bunch spacing. The injected background is increased by a factor of 10 (wrt the 2012 period D data), it corresponds a luminosity of 5.4e34 cm-2s-1. The factor 2 comes from the 25 ns bunch spacing that reduces <mu> wrt 50 ns running.The samples were produced by Felix. • wget http://pcphmpi00/NSW_production/download_all.sh [pcphmpi00] bash download_all.sh • In both cases the generated Sim hits are run through the fast • digitization for the NSW detectors and analyzed. • In the fast digitization the energy thresholds for the sTgc and • MicroMegas were put to the value of 1 MeV.

13. Comparison InjectionMDT and Overlay x 10 NSW layout Cross check only performed for EI MDTs: the |eta|>2 chambers on the Inner wheel Injection method overestimates the rate by a factor 1.5

14. Comparison PileUp vs InjectionMDT and MicroMegas NSW layout EI MDTs: the |eta|>2 chambers on the Inner wheel The MDTs and CSC near beamline are replaced by MM and sTgc Note that in the EI the Pile Up Simulation under estimates the rate wrt Overlay and Injection method

15. Comparison PileUp vs InjectionsTGCs

16. Occupancy PileUpLuminosity of 5.4e34 cm-2s-1 @ 25 ns STgc only for current BC MM assumes four strips firing per gasgap

17. Occupancy Injection method More trustworthy because they extrapolate the measured particle fluxes.

18. Conclusions • Results for two methods for the occupancy of the NSW • Detectors. The Full Sim predicts rates in the NSW detectors • that are a factor 3-4 higher than the Injection Method. • This could be due to the fact that the in the digitization the • Energy threshold are put too low. • Here the results for the injection method are quoted. • Maximum occupancy @ luminosity of 5.4e34 cm-2s-1: • Micromegas 2.5% • sTGC pads 0.5% • sTGC strips 0.1% • sTGC wires 0.4% • The systematic uncertainty on these numbers could be a • factor 1.5 (as shown in the EI test). • These numbers could be quoted in the TDR. • Both the Pile Up and the Injection samples can be used for • e.g. NSW segment or track reconstruction studies in a high • background environment.