Since BBC modules are very old and configuration slightly changed, simulated BBC data doesn't match to data.

BBC response function for simulation developed on 2002 year
To calibrate the BBC simulation, we compared 1 MIP of BBC channels with data and modified BBC response function parameters which is commented by Akio.

Data set: pp500_production_rhicf_2017 
Simulation set: Pythia8 Detroit, at pp 510 GeV

Note: Data used RHICf trigger, there are no constrain to BBC trigger

Figure1. Sum of ADC distribution for BBC modules, East small, East Large, West small, and West Large.



Figure2. Example 1 MIP distribution for East Small BBC channels with data and MC

Existing BBC ADC simulation is upto 256 ADC and let the 1 MIP for each channel to 18 ADC
However, BBC DAQ module changed to 4096 ADC and 1MIP placed around 150 ADC
(Akio's comments)

As per comments, two parameters are modified, 

NADCbins = 256 ->  4096
pC_perADCbin = 0.25 -> 0.03

drupal.star.bnl.gov/STAR/system/files/BBCSim_modifiedPars_compare.pdf

This slide present the modified result
But Large modules are not consistent to data and each channels also slightly different with data

For each channel, I modified light yield, resolution, and so on to calibrate to match the data.
In this final slide, MC tag correspond to modified only two parameters version, and Calibrated MC is calibrated each channels version.

drupal.star.bnl.gov/STAR/system/files/BBCSimulation_CalibrationResult.pdf

Final calibrated simulation code also can see via github.com/star-bnl/star-sw/pull/718