[ Identification | Description | Input parameters | Links ]
Guide_gravity_shieldinglogger ComponentModels a rectangular straight guide tube centered on the Z axis, with gravitation handling. The entrance lies in the X-Y plane. The guide can be channeled (nslit,d,nhslit parameters). The guide coating specifications may be entered via different ways (global, or for each wall m-value). Waviness (random) may be specified either globally or for each mirror type. Side chamfers (due to substrate processing) may be specified the same way. In order to model a realistic straight guide assembly, a long guide of length 'l' may be splitted into 'nelements' between which chamfers/gaps are positioned. The reflectivity may be specified either using an analytical mode (see Component manual) or as a text file in free format, with 1st column as q[Angs-1] and 2nd column as the reflectivity R in [0-1]. For details on the geometry calculation see the description in the McStas component manual. There is a special rotating mode in order to approximate a Fermi Chopper behaviour, in the case the neutron trajectory is nearly linear inside the chopper slits, i.e. the neutrons are fast w/r/ to the chopper speed. Slits are straight, but may be super-mirror coated. In this case, the component is NOT centered, but located at its entry window. It should then be shifted by -l/2. Example: Guide_gravity(w1=0.1, h1=0.1, w2=0.1, h2=0.1, l=12, R0=0.99, Qc=0.0219, alpha=6.07, m=1.0, W=0.003) %VALIDATION May 2005: extensive internal test, all problems solved Validated by: nslit. Lieutenant
| Name | Unit | Description | Default | |
| w1 | (m) Width at the guide entry | |||
| h1 | (m) Height at the guide entry | |||
| w2 | (m) Width at the guide exit. If 0, use w1. | 0 | ||
| h2 | (m) Height at the guide exit. If 0, use h1. | 0 | ||
| l | (m) length of guide | |||
| R0 | (1) Low-angle reflectivity | 0.995 | ||
| Qc | (AA-1) Critical scattering vector | 0.0218 | ||
| alpha | (AA) Slope of reflectivity | 4.38 | ||
| m | (1) m-value of material. Zero means completely absorbing. m=0.65 | 1.0 | ||
| W | (AA-1) Width of supermirror cut-off | 0.003 | ||
| nslit | (1) Number of vertical channels in the guide (>= 1) | 1 | ||
| d | (m) Thickness of subdividing walls | 0.0005 | ||
| mleft | (1) m-value of material for left. vert. mirror | -1 | ||
| mright | (1) m-value of material for right. vert. mirror | -1 | ||
| mtop | (1) m-value of material for top. horz. mirror | -1 | ||
| mbottom | (1) m-value of material for bottom. horz. mirror | -1 | ||
| nhslit | (1) Number of horizontal channels in the guide (>= 1). | 1 | ||
| G | (m/s2) Gravitation norm. 0 value disables G effects. | 0 | ||
| aleft | (1) alpha-value of left vert. mirror | -1 | ||
| aright | (1) alpha-value of right vert. mirror | -1 | ||
| atop | (1) alpha-value of top horz. mirror | -1 | ||
| abottom | (1) alpha-value of left horz. mirror | -1 | ||
| wavy | (deg) Global guide waviness | 0 | ||
| wavy_z | (deg) Partial waviness along propagation axis | 0 | ||
| wavy_tb | (deg) Partial waviness in transverse direction for top/bottom mirrors | 0 | ||
| wavy_lr | (deg) Partial waviness in transverse direction for left/right mirrors | 0 | ||
| chamfers | (m) Global chamfers specifications (in/out/mirror sides). | 0 | ||
| chamfers_z | (m) Input and output chamfers | 0 | ||
| chamfers_lr | (m) Chamfers on left/right mirror sides | 0 | ||
| chamfers_tb | (m) Chamfers on top/bottom mirror sides | 0 | ||
| nelements | (1) Number of sections in the guide (length l/nelements). | 1 | ||
| nu | (Hz) Rotation frequency (round/s) for Fermi Chopper approximation | 0 | ||
| phase | (deg) Phase shift for the Fermi Chopper approximation | 0 | ||
| reflect | (str) Reflectivity file name. Format [q(Angs-1) R(0-1)] | "NULL" |
| AT ( | , | , | ) RELATIVE | |||
|---|---|---|---|---|---|---|
| ROTATED ( | , | , | ) RELATIVE |
Guide_gravity_shieldinglogger.comp.
[ Identification | Description | Input parameters | Links ]
Generated on 2024-01-03 11:47:43