GEM Jaws Manager

Gem jaws are a set of 5 jaws which work in concert to limit the beam of neutrons reaching the sample (see the Jaws Manager page). The 5 jaws are ordered 1 nearest the beam and 5 nearest the sample.

The parameters are (use Jaws Manager for reference):

Letter	Parameter	Value	Notes
c	Collimator position	0 mm	No collimator so beam tapered from moderator
j1	Jaw 1 position	6322 mm	Distance from moderator
j2	Jaw 2 position	8128 mm	Distance from moderator
j3	Jaw 3 position	10329 mm	Distance from moderator
j4	Jaw 4 position	12643 mm	Distance from moderator
j5	Jaw 5 position	15389 mm	Distance from moderator
s	Sample position	17000 mm	Distance from moderator
w	Width of moderator	user set
h	Height of moderator	user set
x	Width at sample	user set
y	Height at sample	user set

Setup

The control files for the nimrod jaws are part of the galil motor set up and are per instrument. There is an example in ...\EPICS\support\motorExtensions\master\settings\gem_jaws\*.cmd which would need to be copied to C:\Instrument\Settings\config\<instrument host name>\configurations\galil. IOC System tests also exist for the logic.