Particle Sources

point A point source can specify the x,y and z coordinates of the point. All particles will emit from this point. The point is visualized by a sphere. The radius of this sphere is controlled by the representationRadius property, it has no effect on the simulation.

surface To create a surface source first create a Sphere, Box, or Cylinder CSG object. It must then be assigned the Material Source to designate that it is being used as a particle source. At this time any Cylinder or Box source must be axis-aligned. All particles will emit from the surface.

volume To create a volume source first create a Sphere, Box, or Cylinder CSG object. It must then be assigned the Material Source to designate that it is being used as a particle source. At this time any Cylinder or Box source must be axis-aligned.

plane A plane source will emit particles from the 2D plane specified. The available types of planes are.

• xy plane This is a rectangular plane on the xy axis.
  • offset The z coordinate of the plane.
  • xMin The lower x coordinate of the plane.
  • xMax The upper x coordinate of the plane.
  • yMin The lower y coordinate of the plane.
  • yMax The upper y coordinate of the plane.
• xz plane This is a rectangular plane on the xz axis.
  • offset The y coordinate of the plane.
  • xMin The lower x coordinate of the plane.
  • xMax The upper x coordinate of the plane.
  • zMin The lower z coordinate of the plane.
  • zMax The upper z coordinate of the plane.
• yz plane This is a rectangular plane on the yz axis.
  • offset The x coordinate of the plane.
  • yMin The lower y coordinate of the plane.
  • yMax The upper y coordinate of the plane.
  • zMin The lower z coordinate of the plane.
  • zMax The upper z coordinate of the plane.
• xy ellipsis An ellipsis (or circle) on the xy plane
  • rX The x-radius of the ellipsis.
  • rY The y-radius of the ellipsis.
  • x The center of the ellipsis on the x axis.
  • y The center of the ellipsis on the y axis.
  • z The center of the ellipsis on the z axis.
• xz ellipsis An ellipsis (or circle) on the xz plane
  • rX The x-radius of the ellipsis.
  • rZ The z-radius of the ellipsis.
  • x The center of the ellipsis on the x axis.
  • y The center of the ellipsis on the y axis.
  • z The center of the ellipsis on the z axis.
• yz ellipsis An ellipsis (or circle) on the yz plane
  • rY The y-radius of the ellipsis.
  • rZ The z-radius of the ellipsis.
  • x The center of the ellipsis on the x axis.
  • y The center of the ellipsis on the y axis.
  • z The center of the ellipsis on the z axis.

number of particles per event This is the number of particles to emit for each event.

particle type The type of particle to emit. The available particles are:

• electron
• proton
• neutron
• positron
• alpha
• gamma
• ion
  • atomic number Atomic number of the ion.
  • nucleon number Number of nucleons in the ion.
  • charge Charge of the ion.
  • nuclear excitation Excitation of the ion.

Angular Dist The type of angular distribution of the particle source.

• Omnidirectional With an omnidirectional angular distribution the fluence for each direction is proportional to the cosine of the angle between the source direction and local noraml of the surface.
  • min theta The minimum angle, 0 degrees corresponds to the -Z axis.
  • max theta The maximum angle, 180 degrees corresponds to the +Z axis.
• Isotropic If emitting from a rectangular slab or plane, the final distribution of particles will not in fact be isotropic as the angle of emission will impact the resulting fluence.
  • min theta The minimum angle, 0 degrees corresponds to the -Z axis.
  • max theta The maximum angle, 180 degrees corresponds to the +Z axis.
• Beam1D A beam1D source will feature a uniform dispersion angle around the beam. The beam angular distribution is only available with planar sources.
  • dispersion angle The dispersion angle of the beam.
  • beam direction Either positive or negative, this will send the particles on the corresponding axial direction.

Energy Spectrum The energy spectrum of the particle source. Options are

• MonoEnergetic

  • mono Energy of the source.
  • units Units of the energy source specified.
  • fluence Unused at this time, will be used in normalization calculations for future releases.

• Linear The linear distribution takes the form y = gradient * energy + intercept

  • min Minimum energy.
  • max Maximum energy.
  • units Units of the energy source.
  • intercept Intercept of the linear curve.
  • gradient The source strength multiplier.

• Power Law The power law distribution takes the form y = gradient * energy ^ alpha

  • min Minimum energy.
  • max Maximum energy.
  • units Units of the energy source.
  • alpha The exponential of the energy distribution.
  • gradient The source strength multiplier.

• Exponential The exponential distribution takes the form \(y = coefficient * e ^(\frac{energy}{eZero})\)

  • min Minimum energy.
  • max Maximum energy.
  • units Units of the energy source.
  • coefficient The source strength multiplier.
  • eZero Base value of the exponential.

• 2 Column File The 2 column file needs to be arranged in order of Energy|Differential Fluence increasing from row to row.

  The integral flux is given in units of particles/cm^2/second^2, while the differential flux is given as particles/cm^2/second^2/MeV

  • file name Name of the file.
  • max integral flux Unused at this time, will be used in normalization calculations for future releases.
  • min integral flux Unused at this time, will be used in normalization calculations for future releases.
  • interpolation type Interpolation between points of the file.
    • linear
    • power-law
    • cubic spline
    • exponential

• Gaussian This gives a guassian energy distribution, and does not allow for a computed normalization to be used.

  • energy center Center of the gaussian distribution.
  • sigma The standard deviation of the gaussian distribution.
  • units The units of the energy center.