[ Identification | Description | Input parameters | Output parameters | Links ]

`Phonon_simple`

Component-
**Author:**Kim Lefmann -
**Origin:**Risoe -
**Date:**04.02.04 -
**Version:**(Unknown)

Single-cylinder shape. Absorption included. No multiple scattering. No incoherent scattering emitted. No attenuation from coherent scattering. No Bragg scattering. fcc crystal n.n. interactions only One phonon branch only -> phonon polarization not accounted for. Bravais lattice only. (i.e. just one atom per unit cell) Algorithm: 0. Always perform the scattering if possible (otherwise ABSORB) 1. Choose direction within a focusing solid angle 2. Calculate the zeros of (E_i-E_f-hbar omega(kappa)) as a function of k_f 3. Choose one value of k_f (always at least one is possible!) 4. Perform the correct weight transformation

Name | Unit | Description | Default |
---|---|---|---|

radius |
m | Outer radius of sample in (x,z) plane | |

yheight |
m | Height of sample in y direction | |

sigma_abs |
barns | Absorption cross section at 2200 m/s per atom | |

sigma_inc |
barns | Incoherent scattering cross section per atom | |

a |
AA | fcc Lattice constant | |

b |
fm | Scattering length | |

M |
a.u. | Atomic mass | |

c |
meV/AA^(-1) | Velocity of sound | |

DW |
1 | Debye-Waller factor | |

T |
K | Temperature | |

target_x | m | position of target to focus at . Transverse coordinate | 0 |

target_y | m | position of target to focus at. Vertical coordinate | 0 |

target_z | m | position of target to focus at. Straight ahead. | 0 |

target_index | 1 | relative index of component to focus at, e.g. next is +1 | 0 |

focus_r | m | Radius of sphere containing target. | 0 |

focus_xw | m | horiz. dimension of a rectangular area | 0 |

focus_yh | m | vert. dimension of a rectangular area | 0 |

focus_aw | deg | horiz. angular dimension of a rectangular area | 0 |

focus_ah | deg | vert. angular dimension of a rectangular area | 0 |

gap | unphysical | [meV] Bandgap energy | 0 |

Name | Unit | Description | Default |
---|---|---|---|

V_rho |
AA^-3 | Atomic density | |

V_my_s |
m^-1 | Attenuation factor due to incoherent scattering | |

V_my_a_v |
m^-1 | Attenuation factor due to absorbtion | |

DV |
|||

parms |

- Source code for
`Phonon_simple.comp`

. - The test/example instrument Test_Phonon.instr.

[ Identification | Description | Input parameters | Output parameters | Links ]

Generated automatically by McDoc, Peter Willendrup <peter.willendrup@risoe.dk> / Tue May 26 13:03:59 2020