Reflectomtery IOC CRISP - ISISComputingGroup/ibex_developers_manual GitHub Wiki

Wiki > The Backend System > Specific Device IOC > Miscellaneous motion control > Reflectometry IOC > CRISP

Specific information about Crisp

Slit 3/Beam blocker

Slit 3 is a tall set of piezo jaws. They are not mounted on a height stage; instead the centre tracks the beam. To set the centre the S3OFFSET parameter must be set and this is the distance from the calculated beam reflected from the sample to the detector to the centre (usually set to 0). Slit 3 can also be set into beam blocker mode for the south jaw. In this state the south jaw will track the beam and the S3OFFSET is the distance from the beam to the jaw in the up direction. The North jaw is controlled with S3N and is measured from the 0 position. The S3S parameter has been hidden in the reflectometry server to make it clear it is not controllable. To enable the S3Offset to set the south slit in the positive direction a user function engineering correction is used which inverts the jaws natural direction (from downwards to upwards).

Blocks

Unlike some reflectometers there is only a single sample height and it is defined by the block:

• Height: Distance from the sample centre of rotation to the sample. This is used to align the sample with the beam.