Geant4 Simulations for the Radon Electric Dipole Moment Search at

3.2.5 Simulated Data
ThecodewaswrittensothattheoutputfromtheGeant4simulationswaswritten
as binary files, containing all the interaction energy, time, and position information
within the simulation. The advantage of writing information in binary files versus
ASCII is its compactness. For example, the number 1000000000 in ASCII would
require 10 bytes to store (10 characters long), whereas if it were represented as an
unsigned binary it would only use 4 bytes. The sheer number of simulations needed
to achieve desirable statistics made use of this compactness. The other option, of
course, was to write histograms and spectra directly from the Geant4 simulation.
This method does not preserve the correlations between event energies, times and
locations that are included in the list-mode binary event data and often desirable
during the analysis phase.
The binary stream was written in small segments which correspond to individual
events. One event represents one β-decay process including the subsequent γ decays
and internal conversion processes until the daughter nucleus reaches its ground state.
Every event in the output stream begins with the hexidecimal flag 0x8000 and ends
with 0xFFFF. The binary data between these flags encompasses all the information
relating to a single decay, including the energy deposited inside detectors, position
information of the γ ray interactions, pair production processes, bremsstrahlung processes,
and their interaction times. See Table 3.1 for a list of all flags used in the data
stream.
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