NOREC, a Monte Carlo code for simulating electron tracks in liquid water

Abstract

The work reported here was originally motivated by a discussion of Monte Carlo computer codes for electron transport in water given in Report No. 130 by the National Council on Radiation Protection and Measurements (NCRP). It was pointed out (correctly) that a published depth-dose distribution calculated by the Oak Ridge electron transport code, OREC, for 800 keV electrons normally incident on a water slab was apparently in error, possibly due to inadequate treatment of elastic scattering. In this paper we describe the replacement of the original OREC elastic cross sections by current ones from the National Institute of Standards and Technology (NIST). This investigation led also to the critical examination and revision of some other parts of the program, as described here. The revised code, which we have renamed NOREC, represents the first substantial review and modification of the Oak Ridge code in a number of years. We also present some comparisons of results calculated with the old and new versions and discuss their implications with respect to earlier studies. We have also written a version of NOREC in C++ language, which is available to other investigators. This paper provides a record of a response to the NCRP published statement and documentation for the revised code, NOREC.

Unified solution of the Boltzmann equation for electron and ion velocity distribution functions and transport coefficients in weakly ionized plasmas

“…Theoretically, such transport is modelled by kinetic methods involving the solution of Boltzmann's equation [5] for the phase-space distribution function, from which the macroscopic properties can be calculated and compared to experiment. In recent times, other techniques such as Monte Carlo [6][7][8], particle in cell (PIC) [9] and hybrid/fluid models have been favoured. Important however is the need to benchmark these techniques against other established techniques.…”

Geant4 Physics Processes for Microdosimetry Simulation: Design Foundation and Implementation of the First Set of Models

“…zero momentum transfer) in electron spectroscopy. A few codes have been developed assuming liquid water [31]- [38] as the transport medium. Several studies have highlighted significant differences between calculations in liquid water and in vapour [41], [42], [63]- [65]; differences related to the phase have also been observed experimentally in comparisons between measurements in water vapour and ice [66].…”

“…Specialized Monte Carlo codes [20]- [38], usually known as "track structure codes", have been developed for microdosimetry calculations for radiobiological studies, like the evaluation of molecular damage [39]. The set of codes cited is not intended to be an exhaustive collection, rather a significant sample representative of the extensive research activity in this field.…”

Monte Carlo simulation of modern techniques of intensity modulated radiation therapy (IMRT)

“…Cho et al used 7 and 18 mgAu/ gr tumor for all the simulations while Jones et al used only 7 mgAu/ gr tumor. In order to calculate microscopic DER (mDER), a combination of MCNP and EGSnrc MC codes was used along with NOREC code [23]. The latest, as mentioned in a previous section, is a track structure code capable to track each electron separately down to 100 eV.…”

“…Traditionally simulations like these were performed with codes specifically created for these types of simulations. The most commonly used are OREC/NOREC [23], TRION [24], ETRAN, [25] but others have been also created from Emfietzoglou et al [26].…”