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

Setup

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