A double L-shaped slit system is installed in the optics hutch downstream after the Double Crystal Monochromator.
The sketch below shows which motor is by which IDL command.
The slit system is water cooled and equipped with limit switches that act on relative motor movements. If the slit is opened too far in x- or z-direction, the according limit switches will be activated and only the motion in closing direction will be allowed.
IDL Commands
Apart from moving each motorseparately, it is also possible to open and close or move the slit by a certain amount w.r.t. to the current center position. These commands works only with relative motions.
| motion | IDL command (relative) | IDL command (absolute) |
|---|---|---|
| left slit by N mm | oh_slit_x1, N | goto_oh_slit_x1, N |
| right slit | oh_slit_x2, N | goto_oh_slit_x2, N |
| lower slit | oh_slit_z1, N | goto_oh_slit_z1, N |
| upper slit | oh_slit_z2, N | goto_oh_slit_z2, N |
| open slit x by N mm | slit_oh, rdx=N | - |
| open slit z by N mm | slit_oh, rdz=N | - |
| move slit x by N mm | slit_oh, rx=N | - |
| move slit z by N mm | slit_oh, rz=N | - |
ZMX motors and OH labels
The table below lists the motor driver position on the ZMX crate for each slit as well as the label on the stages in the Optics hutch.
| Slit | IDL nomenclature | ZMX motor | OH label | Tango alias |
|---|---|---|---|---|
| Left | x1 | 9 | 3X | ohslit_3x |
| Right | x2 | 13 | 1X | ohslit_1x |
| Lower | z1 | 10 | 4Y | ohslit_4y |
| Upper | z2 | 14 | 2Y | ohslit_2y |