In order to establish an understanding of the potential properties of TEPX as luminometer for Phase 2 CMS luminosity measurement, detector simulations are being carried out by the BRIL collaboration. Since for PhaseII the range of pileup values over which the vdM calibration will have to be extrapolated is large with respect to RunII, the linearity of observables accessible with TEPX as a function of pileup is of particular interest.
For this purpose, detailed detector simulations have been started using the CMSSW release 10_4_0_pre2 and the Inner Tracker geometry version 6.1.3. To generate data samples over a large range of pileup, singleneutrino events have been overlaid with a variable number of minimum bias events using the CMSSW mixing module. 100,000 events have been generated for pileup values smaller than 20 and 10,000 events have been used for all larger pileup numbers to limit computing time to reasonable values.
Figure  Caption 

Simulated mean number of clusters as a function of pileup for Disk 1 Ring 1 of the Inner Tracker Endcap Pixel Detector (TEPX). The data points are fitted with a firstorder polynomial in the pileup interval from 0 to 2, and the extrapolation to pileup 200 is shown with a 95% confidence interval. This is done to replicate the principal approach taken with the Van der Meer calibration. 


Simulated mean number of clusters as a function of pileup for Disk 1 Ring 5 of the Inner Tracker Endcap Pixel Detector (TEPX). The data points are fitted with a firstorder polynomial in the pileup interval from 0 to 2, and the extrapolation to pileup 200 is shown with a 95% confidence interval. This is done to replicate the principal approach taken with the Van der Meer calibration. 
Simulated mean number of clusters as a function of pileup for Disk 4 Ring 1 of the Inner Tracker Endcap Pixel Detector (TEPX). The data points are fitted with a firstorder polynomial in the pileup interval from 0 to 2, and the extrapolation to pileup 200 is shown with a 95% confidence interval. This is done to replicate the principal approach taken with the Van der Meer calibration. 

Relative nonlinearity for all rings of all disks of the Inner Tracker Endcap Pixel Detector (TEPX). It is calculated as the relative difference between the data point and the value of the fit function at the respective pileup value. 

Simulated distribution of the permodule data rates for each ring of TEPX at pileup 200 and a trigger rate of 75 kHz. The rates are calculated over all disks of TEPX. 
I  Attachment  History  Action  Size  Date  Who  Comment 

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png  linearity_d1r5_1.png  r1  manage  150.6 K  20190812  12:21  UnknownUser  
png  linearity_d4r1_1.png  r1  manage  149.3 K  20190812  12:19  UnknownUser  
png  linearitydeviation_1.png  r1  manage  100.1 K  20190812  12:21  UnknownUser  
png  ring_rates_1.png  r1  manage  111.3 K  20190812  12:21  UnknownUser  
linearity_d1r1.pdf  r1  manage  35.6 K  20190812  12:13  UnknownUser  
linearity_d1r5.pdf  r1  manage  36.5 K  20190812  12:17  UnknownUser  
linearity_d4r1.pdf  r1  manage  35.7 K  20190812  12:15  UnknownUser  
linearitydeviation.pdf  r1  manage  34.5 K  20190812  12:15  UnknownUser  
ring_rates.pdf  r1  manage  19.1 K  20190812  12:15  UnknownUser 