EGS (program)

Last updated

The EGS (Electron Gamma Shower) computer code system is a general purpose package for the Monte Carlo simulation of the coupled transport of electrons and photons in an arbitrary geometry for particles with energies from a few keV up to several hundreds of GeV. [1] It originated at SLAC but National Research Council of Canada and KEK have been involved in its development since the early 80s.

Contents

Development of the original EGS code ended with version EGS4. Since then two groups have re-written the code with new physics:

EGSnrc

EGSnrc
Developer(s) National Research Council Canada
Initial release2000;24 years ago (2000)
Stable release
v2019a / May 8, 2019;4 years ago (2019-05-08)
Operating system Cross-platform
Type Computational physics
License GNU Affero General Public License
Website nrc.canada.ca/en/research-development/products-services/software-applications/egsnrc-software-tool-model-radiation-transport

EGSnrc is a general-purpose software toolkit that can be applied to build Monte Carlo simulations of coupled electron-photon transport, for particle energies ranging from 1 keV to 10 GeV. It is widely used internationally in a variety of radiation-related fields. The EGSnrc implementation improves the accuracy and precision of the charged particle transport mechanics and the atomic scattering cross-section data. [4] [5] [6] The charged particle multiple scattering algorithm allows for large step sizes without sacrificing accuracy - a key feature of the toolkit that leads to fast simulation speeds. [7] [8] EGSnrc also includes a C++ class library called egs++ that can be used to model elaborate geometries and particle sources.

EGSnrc is open source and distributed on GitHub under the GNU Affero General Public License. Download EGSnrc for free, submit bug reports, and contribute pull requests on a group GitHub page. [9] The documentation for EGSnrc is also available online. [10]

EGSnrc is distributed with a wide range of applications that utilize the radiation transport physics to calculate specific quantities. These codes have been developed by numerous authors over the lifetime of EGSnrc to support the large user community. It is possible to calculate quantities such as absorbed dose, kerma, particle fluence, and much more, with complex geometrical conditions. One of the most well-known EGSnrc applications is BEAMnrc, which was developed as part of the OMEGA project. This was a collaboration between the National Research Council of Canada and a research group at the University of Wisconsin–Madison. All types of medical linear accelerators can be modelled using the BEAMnrc's component module system. [11]

See also

Related Research Articles

<span class="mw-page-title-main">Particle physics</span> Study of subatomic particles and forces

Particle physics or high-energy physics is the study of fundamental particles and forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the scale of protons and neutrons, while the study of combination of protons and neutrons is called nuclear physics.

<span class="mw-page-title-main">Monte Carlo method</span> Probabilistic problem-solving algorithm

Monte Carlo methods, or Monte Carlo experiments, are a broad class of computational algorithms that rely on repeated random sampling to obtain numerical results. The underlying concept is to use randomness to solve problems that might be deterministic in principle. The name comes from the Monte Carlo Casino in Monaco, where the primary developer of the method, physicist Stanislaw Ulam, was inspired by his uncle's gambling habits.

<span class="mw-page-title-main">Scintillator</span> Material which glows when excited by ionizing radiation

A scintillator is a material that exhibits scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate. Sometimes, the excited state is metastable, so the relaxation back down from the excited state to lower states is delayed. The process then corresponds to one of two phenomena: delayed fluorescence or phosphorescence. The correspondence depends on the type of transition and hence the wavelength of the emitted optical photon.

In plasma physics, the particle-in-cell (PIC) method refers to a technique used to solve a certain class of partial differential equations. In this method, individual particles in a Lagrangian frame are tracked in continuous phase space, whereas moments of the distribution such as densities and currents are computed simultaneously on Eulerian (stationary) mesh points.

In condensed matter physics, scintillation is the physical process where a material, called a scintillator, emits ultraviolet or visible light under excitation from high energy photons or energetic particles. See scintillator and scintillation counter for practical applications.

<span class="mw-page-title-main">Two-photon physics</span> Branch of particle physics concerning interactions between two photons

Two-photon physics, also called gamma–gamma physics, is a branch of particle physics that describes the interactions between two photons. Normally, beams of light pass through each other unperturbed. Inside an optical material, and if the intensity of the beams is high enough, the beams may affect each other through a variety of non-linear effects. In pure vacuum, some weak scattering of light by light exists as well. Also, above some threshold of this center-of-mass energy of the system of the two photons, matter can be created.

Monte Carlo N-Particle Transport (MCNP) is a general-purpose, continuous-energy, generalized-geometry, time-dependent, Monte Carlo radiation transport code designed to track many particle types over broad ranges of energies and is developed by Los Alamos National Laboratory. Specific areas of application include, but are not limited to, radiation protection and dosimetry, radiation shielding, radiography, medical physics, nuclear criticality safety, detector design and analysis, nuclear oil well logging, accelerator target design, fission and fusion reactor design, decontamination and decommissioning. The code treats an arbitrary three-dimensional configuration of materials in geometric cells bounded by first- and second-degree surfaces and fourth-degree elliptical tori.

In particle physics, a shower is a cascade of secondary particles produced as the result of a high-energy particle interacting with dense matter. The incoming particle interacts, producing multiple new particles with lesser energy; each of these then interacts, in the same way, a process that continues until many thousands, millions, or even billions of low-energy particles are produced. These are then stopped in the matter and absorbed.

<span class="mw-page-title-main">Electron scattering</span> Deviation of electrons from their original trajectories

Electron scattering occurs when electrons are displaced from their original trajectory. This is due to the electrostatic forces within matter interaction or, if an external magnetic field is present, the electron may be deflected by the Lorentz force. This scattering typically happens with solids such as metals, semiconductors and insulators; and is a limiting factor in integrated circuits and transistors.

In particle physics, the parton model is a model of hadrons, such as protons and neutrons, proposed by Richard Feynman. It is useful for interpreting the cascades of radiation produced from quantum chromodynamics (QCD) processes and interactions in high-energy particle collisions.

<span class="mw-page-title-main">Stopping power (particle radiation)</span> Retarding force acting on charged particles due to interactions with matter

In nuclear and materials physics, stopping power is the retarding force acting on charged particles, typically alpha and beta particles, due to interaction with matter, resulting in loss of particle kinetic energy. Stopping power is also interpreted as the rate at which a material absorbs the kinetic energy of a charged particle. Its application is important in a wide range of thermodynamic areas such as radiation protection, ion implantation and nuclear medicine.

In high-energy physics, the Landau–Pomeranchuk–Migdal effect, also known as the Landau–Pomeranchuk effect and the Pomeranchuk effect, or simply LPM effect, is a reduction of the bremsstrahlung and pair production cross sections at high energies or high matter densities. It is named in honor of Lev Landau, Isaak Pomeranchuk and Arkady Migdal.

FLUKA is a fully integrated Monte Carlo simulation package for the interaction and transport of particles and nuclei in matter. FLUKA has many applications in particle physics, high energy experimental physics and engineering, shielding, detector and telescope design, cosmic ray studies, dosimetry, medical physics, radiobiology. A recent line of development concerns hadron therapy.

<span class="mw-page-title-main">Monte Carlo method for photon transport</span>

Modeling photon propagation with Monte Carlo methods is a flexible yet rigorous approach to simulate photon transport. In the method, local rules of photon transport are expressed as probability distributions which describe the step size of photon movement between sites of photon-matter interaction and the angles of deflection in a photon's trajectory when a scattering event occurs. This is equivalent to modeling photon transport analytically by the radiative transfer equation (RTE), which describes the motion of photons using a differential equation. However, closed-form solutions of the RTE are often not possible; for some geometries, the diffusion approximation can be used to simplify the RTE, although this, in turn, introduces many inaccuracies, especially near sources and boundaries. In contrast, Monte Carlo simulations can be made arbitrarily accurate by increasing the number of photons traced. For example, see the movie, where a Monte Carlo simulation of a pencil beam incident on a semi-infinite medium models both the initial ballistic photon flow and the later diffuse propagation.

<span class="mw-page-title-main">Collision cascade</span> Series of collisions between nearby atoms, initiated by a single energetic atom

In condensed-matter physics, a collision cascade is a set of nearby adjacent energetic collisions of atoms induced by an energetic particle in a solid or liquid.

Stopping and Range of Ions in Matter (SRIM) is a group of computer programs which calculate interactions between ions and matter; the core of SRIM is a program called Transport of Ions in Matter (TRIM). SRIM is popular in the ion implantation research and technology community, and also used widely in other branches of radiation material science.

<span class="mw-page-title-main">Binary collision approximation</span> Heuristic used in simulations of ions passing through solids

In condensed-matter physics, the binary collision approximation (BCA) is a heuristic used to more efficiently simulate the penetration depth and defect production by energetic ions in solids. In the method, the ion is approximated to travel through a material by experiencing a sequence of independent binary collisions with sample atoms (nuclei). Between the collisions, the ion is assumed to travel in a straight path, experiencing electronic stopping power, but losing no energy in collisions with nuclei.

Xie George Xu was the Edward E. Hood Chair Professor of Engineering at Rensselaer Polytechnic Institute (RPI), Troy, New York, United States, before he relocated in 2020 to China and joined the faculty of the University of Science and Technology of China.

A charged particle accelerator is a complex machine that takes elementary charged particles and accelerates them to very high energies. Accelerator physics is a field of physics encompassing all the aspects required to design and operate the equipment and to understand the resulting dynamics of the charged particles. There are software packages associated with each domain. The 1990 edition of the Los Alamos Accelerator Code Group's compendium provides summaries of more than 200 codes. Certain codes are still in use today, although many are obsolete. Another index of existing and historical accelerator simulation codes is located at the CERN CARE/HHH website.

Serpent is a continuous-energy multi-purpose three-dimensional Monte Carlo particle transport code. It is under development at VTT Technical Research Centre of Finland since 2004. Serpent was originally known as Probabilistic Scattering Game (PSG) from 2004 to the first pre-release of Serpent 1 in October 2008. The development of Serpent 2 was started in 2010. The current stable version Serpent 2.2.0 was released in May 2022.

References

  1. Nelson, W. R.; Hirayama, H.; Rogers, D. W. O. (1985). "The EGS4 Code System". Report SLAC–265, Stanford Linear Accelerator Center, Stanford, California.
  2. Canada, Government of Canada. National Research Council. "EGSnrc: software tool to model radiation transport - National Research Council Canada". www.nrc-cnrc.gc.ca. Retrieved 1 November 2018.
  3. "EGS at KEK Web Page". rcwww.kek.jp. Retrieved 1 November 2018.
  4. Kawrakow, I (2000). "Accurate condensed history Monte Carlo simulation of electron transport. I. EGSnrc, the new EGS4 version". Medical Physics. 27 (3): 485–98. Bibcode:2000MedPh..27..485K. doi: 10.1118/1.598917 . PMID   10757601.
  5. Kawrakow, I (2000). "Accurate condensed history Monte Carlo simulation of electron transport. II. Application to ion chamber response simulations: I.". Medical Physics. 27 (3): 499–513. Bibcode:2000MedPh..27..499K. doi:10.1118/1.598918. PMID   10757602.
  6. Borg, J.; Kawrakow, I.; Rogers, D. W. O.; Seuntjens, J. P. (2000). "Monte Carlo study of Spencer-Attix cavity theory at low photon energies". Medical Physics. 27 (8): 1804–13. Bibcode:2000MedPh..27.1804B. doi:10.1118/1.1287054. PMID   10984227.
  7. Kawrakow, I; Bielajew, A. F. (1998). "On the representation of electron multiple elastic-scattering distributions for Monte Carlo calculations". Nuclear Instruments and Methods in Physics Research Section B. 134 (3–4): 325–36. Bibcode:1998NIMPB.134..325K. doi:10.1016/S0168-583X(97)00723-4.
  8. Kawrakow, I; Bielajew, A. F. (1998). "On the condensed history technique for electron transport". Nuclear Instruments and Methods in Physics Research Section B. 142 (3): 253–80. Bibcode:1998NIMPB.142..253K. doi:10.1016/S0168-583X(98)00274-2.
  9. "nrc-cnrc/EGSnrc". GitHub. Retrieved 1 November 2018.
  10. "EGSnrc". nrc-cnrc.github.io. Retrieved 1 November 2018.
  11. Rogers, D. W. O.; Faddegon, B. A.; Ding, G. X.; Ma, C.-M.; We, J.; Mackie, T. R. (1995). "BEAM: A Monte Carlo code to simulate radiotherapy treatment units". Medical Physics. 22 (5): 503–524. Bibcode:1995MedPh..22..503R. doi:10.1118/1.597552. PMID   7643786.