Pohang Neutron Facility (PNF) is a pulsed neutron facility based on the 100-MeV electron linear accelerator. It was constructed for nuclear data production in Korea, and it consists of an electron linear accelerator, a watercooled Ta target with a water moderator and a time-offlight path with an 11 m length. The 100-MeV electron linac uses a thermionic RF-gun, an alpha magnet, four quadrupole m...

introduction: in brachytherapy, radioactive sources are placed close to the tumor, therefore, small changes in their positions can cause large changes in the dose distribution. this emphasizes the need for computerized treatment planning. the usual method for treatment planning of cervix brachytherapy uses conventional radiographs in the manchester system. nowadays, because of their advantages ...

Since 2005 the nodal diffusion based code system, OSCAR-3, was used for reactor support calculations of operational cycles High Flux Reactor in Petten, The Netherlands. OSCAR uses a two-step deterministic calculation, which homogenized cross sections are generated lattice environments using neutron transport simulations, and then passed to core simulator model full reactor. Limitations OSCAR-3 ...

In this paper, we show that concentrations of manufactured carbon-based nanoparticles (MCNPs) in aquatic sediments will be negligible compared to levels of black carbon nanoparticles (BCNPs). This is concluded from model calculations accounting for MCNP sedimentation fluxes, removal rates due to aggregation or degradation, and MCNP burial in deeper sediment layers. The resultant steady state MC...

background: palladium-103 (103pd) is a brachytherapy source for cancer treatment. the monte carlo codes are usually applied for dose distribution and effect of shieldings. monte carlo calculation of dose distribution in water phantom due to a med3633 103pd source is presented in this work. materials and methods: the dose distribution around the 103pd model med3633 located in the center of 30×30...

It is of interest to discern the energy-dependence of American Association of Physicists in Medicine (AAPM) TG-43 brachytherapy dosimetry parameters. Using Monte Carlo calculation geometry and techniques (MCNP), dependence of these parameters was calculated as a function of photon energy, in general, and for the MED3633 103Pd source using a discretized approach. Results were weighted and summed...

NCRP 151 provides very detailed examples demonstrating the necessary concerns for shielding a conventional radiotherapy vault with a maze where the useful beam is parallel to the maze. However, it provides little guidance on how to properly shield a vault with the maze-wall acting as part of a compound primary barrier. We have modeled a new radiotherapy vault with this configuration and assesse...

The MCNP Monte Carlo radiation transport code was used for calculation of scatter distribution and scatter-toprimary ratio (SPR) for different tube voltages, phantom thicknesses and field size in diagnostic radiology. Subsequently, the effect of grid’s design parameters such as strip density, grid ratio, interspace material and lead-tointerspace ratio on scatter rejection was investigated by ca...

The Monte Carlo calculation of the effective (i.e. adjoint weighted) neutron generation time Keff, especially for continuous energy simulations, is not straightforward nor standard in Monte Carlo codes. The use of the non-adjoint weighted neutron generation time K (standard in most Monte Carlo codes) as an approximation of the effective one can lead to a serious bias. We show here that the diff...

The practical calibration rooms for neutron measuring devices are relatively small, where a large amount of room-reflected neutrons arise. Moreover the different structures of neutron irradiation apparatus influence the neutron spectrum and reference dose considerably. Therefore the influence of the neutron scattering was investigated in the three calibration rooms in different sizes and instal...