Preshower layers PS1 & PS2 with a cut on maximum light yield (for photon/hadron separation):

photon_survival = 0.98
hadron_survival = 0.05

Preshower layer PS3 with a cut on maximum light yield (for electron/hadron separation):

electron_survival = 0.10
hadron_survival = 0.80

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Electromagnetic shower E_em from n_i hadron interactions in the FMS:

E_em = 1. - pow(2./3., n_i) * energy_of_hadron

with the cumulative probability for n_i nuclear interactions in FMS (length = 1.8 lambda_int):

TRandom3 *my_random = new TRandom3();
p_i = my_random->Rndm();
if(p_i > 0.162) n_i=1;
if(p_i > 0.457) n_i=2;
if(p_i > 0.725) n_i=3;
if(p_i > 0.888) n_i=4;
if(p_i > 0.962) n_i=5;
if(p_i > 0.989) n_i=6;
if(p_i > 0.997) n_i=7;
if(p_i > 0.999) n_i=8;

(*) Anything above 8 is largely diluted by the stochastic term in the shower.

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Energy resolution in FMS (also applies to hadronic energy deposit above):

sigma_PbGl_rootE = 0.10; // stochastic term / sqrt(E)
sigma_PbGl_const = 0.005; // constant term

(*) The stochastic term for PbGl detectors are usually on the order of less than 8%/sqrt(E), but previous studies with the FMS were as large as 14%. Since we include the converter in the preshower, we assume 10% for now.