OPEN NSF COMMUNICATION
A program written in Igor Pro is used for monitoring and controlling the power supplies and a python bridge is used to communicate over the network between the NICE instrument control program and the Igor program.
- On the 3He computer (member of the Spin Filter team only):
- Open the Igor program
- Open the python communication bridge
- In the NICE client on the User Console:
- Select the menu option Window > Configure Devices
- Install 'he3BackPolarization'
- NOTE: he3FrontPolarization is not usually applicable to SANS
- If communication is not working, ask Spin Filter Team to check the 3He computer
REGISTER SPIN FILTERS
NICE maintains a list of known cells and related spin filter parameters. By registering a cell through NICE, cell information will be saved in the data file that can be used during the data reduction process.
- In the NICE console:
- type 'registerHe3cell <cellName> <deviceName>'
- e.g. 'registerHe3cell Burgundy he3BackPolarization'
SETUP CELL IN/OUT POSITIONS
- Manually place the Spin Filter Solenoid on the cradle
- NG7 SANS: the Spin Filter installs inside Sample Chamber
- Set the lab jack to the correct height for a shielded solenoid
- Manually install the solenoid cradle onto lab jack
- Manually place the shielded solenoid onto the cradle
- Ensure solenoid is centered on the beam using laser alignment
- In NICE, define the cell IN and OUT positions
- VSANS: Spin Filter installs onto 3He Platform
PERFORMING AN EXPERIMENT
SPIN FILTER MEASUREMENTS
The following steps are necessary transmission measurements (TM) for accurate data reduction: cell in, cell out, and beam block or background (only 1 per configuration). These measurements should be taken at the beginning of each experiment to determine the spin filter starting polarization as a group as well as 2-3 cell in/cell out TMs during each experimental cell lifetime. A final measurement group should be taken before changing spin filters or ending an experiment.
SPIN FILTER TRANSMISSION MEASUREMENTS
- Set # of attenuators (must be the same for all grouped measurements)
- Count cell in beam (minimum 2000 counts for statistics, typically 180 sec)
- Count cell out of beam (minimum 2000 counts for statistics, typically 180 sec)
- Count beam block or background (typically same count time as above)
- NOTE: Background measurement should be taken for each configuration