SANS POLARIZED BEAM

EXPERIMENT SETUP

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
    • Manually place the shielded solenoid onto the cradle
    • Follow guide for either Low Field Setup.pdf or High Field Setup.pdf
    • In NICE, define the cell IN and OUT positions

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