Slits

Slits are introduced to Online by defining the symbol slit_names in /online_dir/exp_ini.exp, e.g.:

slit_names = (slt1, slt2)

slt1_left   =  mot21
slt1_right  =  mot22
slt1_top    =  mot23
slt1_bottom =  mot24
slt2_left   =  mot25
slt2_right  =  mot26
slt2_top    =  mot27
slt2_bottom =  mot28

The symbol slit_names holds the generic part of the slit names. In addition the jaws must be selected by: slt1_left = mot21, etc. After a slit is specified, the following degrees of freedom are available: cx, cy, dx, dy, left, right, top, bottom. They are presented in the slit selector, see 11.5. This widget can be called from the Scan GUI or the Move GUI.

The coordinate system: z points in the direction of the photons, y points upwards, x completes the right-handed coordinate system. 'right' points in the x-direction, like in school.

Figure 11.5: The Slit Selector