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:
- These steps can only be performed by a member of the 3He team
- Open the Igor program
- Open the python communication bridge
- In the NICE program:
- Select the menu option Window > Device Configuration
- Install 'he3FrontPolarization' or 'he3BackPolarization' or both
- NOTE: he3FrontPolarization is not usually applicable to SANS
- Type a command in console to check communication
- e.g. 'read he3BackPolarization' --> returns cell state (UP/DOWN)
- e.g. IFTalk HeInterface “He3AnaEnabled()” in the console --> Returns “1 = 3He analyzer Enabled?” if the 3He interface is communicating
- JRK Note: I don't think we can send IFTalk commands directly to the device anymore, but I will need to check.
- 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 'move registerHe3cell <cellName> <deviceName>'
- e.g. 'move 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
- In NICE, define the cell IN and OUT positions
- 'move backPolarizationGroup.inPosition <value>' and 'move backPolarizationGroup.inPosition <value>'
- 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