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Polaris Jaws
Wiki > The Backend System > Specific Device IOC > Jaws and Slits > Polaris Jaws
Polaris jaws are a set of 5 jaws which work in concert to limit the beam of neutrons reaching the sample (see Jaws Manager). Jaws 1-4 are instrument user controlled and work together in a pyramid shape to reduce the beam size in stages. The gap in each jaw set is set based on its distance from the sample. There are documents stored in sharepoint. The 5 jaws are ordered 1 nearest the beam and 5 nearest the sample. Jaw set 5 is under on instrument scientist control. To change these settings the user must put the GUI into management mode.
The parameters are (with reference to the diagram in Jaws Manager):
| Letter | Parameter | Value | Notes |
|---|---|---|---|
| c | Collimator position | 1610 mm | Distance from moderator |
| j1 | Jaw 1 position | 6502 mm | Distance from moderator |
| j2 | Jaw 2 position | 9440 mm | Distance from moderator |
| j3 | Jaw 3 position | 11085 mm | Distance from moderator |
| j4 | Jaw 4 position | 11735 mm | Distance from moderator |
| j5 | Jaw 5 position | 13175 mm | Distance from moderator |
| s | Sample position | 14000 mm | Distance from moderator |
| w | Width of Collimator | 82.2 | |
| h | Height of Collimator | 79.4 | |
| x | Width at sample | user set | |
| y | Height at sample | user set |
The control files for the polaris jaws are part of the galil motor set up and are per instrument. There is an example in ...\EPICS\support\motorExtensions\master\settings\polaris_jaws\*.cmd which would need to be copied to C:\Instrument\Settings\config\<instrument host name>\configurations\galil