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Table 2 Simulation conditions used in this work, displayed as per the scheme proposed by the RECORDS report [12]

From: PRIMO Monte Carlo software benchmarked against a reference dosimetry dataset for 6 MV photon beams from Varian linacs

Item Description References
Code PRIMO v. 0.3.1.1600, based on penEasy/penelope 2011, and DPM algorithm [26]
Timing PSF Simulation time: ≈10 d on an Intel Xeon E5-2670 v3, 24 cores @ 2.3 GHz, 64 GB RAM, Windows Server 2016  
Timing 10×10 cm2 field Simulation time with DPM: 5.5 h on an Intel Xeon E5-2620. 2 CPU (×6 cores) @ 2.00 GHz, 32 GB RAM, Windows 7. Other fields: CPU time linearly proportional to the field area.  
Source description Clinac 2100 PSF stage 1 simulated with PRIMO, 6 MV, initial energy: 5.4 MeV, energy FWHM: 0, focal spot FWHM: 0, beam divergence: 0, field size: 40 ×40 cm2. Simulation engine: penEasy/penelope. Histories: 850 ×106. PSF size: 150 GB  
Source description TrueBeam PSF stage 1 simulated with PRIMO, FakeBeam, 6 MV FFF, initial energy: 5.8 MeV, energy FWHM: 0.058 MeV, focal spot FWHM: 0.15 cm, beam divergence: 0, field size: 40 ×40 cm2. Simulation engine: penEasy/ penelope. Histories: 850 ×106. PSF size: 237 GB  
Cross sections penelope 2011 and DPM. [4, 6]
Transport parameters PRIMO default transport parameters for 6 MV from Clinac 2100 and for 6 MV FFF from FakeBeam [20]
Variance-reduction techniques PSF simulations: splitting roulette. Movable–skins technique applied to the simulation of primary collimator, jaws and MLC. Water phantom simulations: particle splitting (×170, factor empirically determined) [20, 23, 24]
Scored quantities Absorbed dose to a voxelized water phantom of 30.2 ×30.2×30 cm3, voxel size 0.2 ×0.2×0.2 cm3. Simulation engine: DPM and penEasy/ penelope 2011  
# histories/ statistical uncertainty 850 ×106 histories. Statistical uncertainty of the calculated dosimetric parameters typically below 2% (k=2), estimated with the history–by–history method of penelope 2011 [4, 20]
Post-processing No smoothing or de–noising was applied to the simulation results.