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Updated: May 10, 2026
Characterization of SiN Integrated Optical Phased Arrays on a Wafer-Scale Test Station
Published on: April 1, 2020
A comprehensive procedure for characterizing arbitrary azimuthally symmetric photon beams
Ahad Ollah Ezzati1, Mostafa Sohrabpour1, Seied Rabi Mahdavi2
1Department of Energy Engineering, Sharif University of Technology, Tehran, Iran.
Purpose:
A new Monte Carlo (MC) source model (SM) has been developed for azimuthally symmetric photon beams.
Methods:
The MC simulation tallied phase space file (PSF) is divided into two categories depending on the relationship of the particle track line to the beam central axis: multiple point source (MPS) and spatial mesh based surface source (SMBSS). To validate this SM, MCNPX2.6 was used to generate two PSFs for a 6 MV photon beam from a Varian 2100C/D linear accelerator.
Results:
PDDs and profiles were calculated using the SM and original PSF for different field sizes from 5 × 5 to 40 × 40 cm2. Agreement was within 2% of the maximum dose at 100 cm SSD and 2.5% of the maximum dose at 200 cm SSD for beam profiles at depths of 3.5 cm and 15 cm with respect to the original PSF. Differences between the source model and the PSF in the out-of-field regions were less than 0.5% of the profile maximum value at 100 cm SSD. Differences between measured and calculated points were less than 2% of the maximum dose or 2 mm distance to agreement (DTA) at 100 cm SSD.
Conclusions:
This SM is unique in that it accounts for a higher level of energy dependence on the particle's direction and it is independent from accelerator components, unlike other published SMs. The model can be applied to any arbitrary azimuthally symmetric beam and has source biasing capabilities that significantly increase the simulation speed up to 3300 for certain field sizes.
