How to use Borealis
How to run an experiment
The user must create a configuration file to initialize all python objects composing the spectrometer and to establish all communication with the hardware.
An example of configuration file for a dummy spectrometer is given in \examples\dummy_spectrometer.py. This dummy spectrometer consists in one dummy controller, a dummy detector and a Si(12 8 4) analyzer crystal. A step motor “mono” is positioning the monochromator, with an offset of -3 degrees. A pseudo-motor “theta” moves the motor “mono” in order to reach a specific Bragg angle theta, according to a positioning law theta_to_mono. A pseudo-motor “energy” moves the pseudo-motor “theta” to the energy position in keV corresponding to the Bragg angle obeying the Bragg law:
“theta” and “energy” are both linked to a detector, allowing to perform an acquisition while scanning, i.e. at each point of a user-define trajectory. A pseudo-motor “energy_no_det” is identical to “energy”, but is linked to no detector.
One starts the interactive ipython session and instantiate the dummyspectrometer with:
ipython -i examples/dummy_spectrometer.py
Within the interactive ipython session, the user can interact with the spectrometer directly through call to object methods such as theta.amove() or energy.scan(), or via a script. A script example for an energy scan between 17.1 keV and 17.2 keV is given in examples\script_dummy_spectrometer.py.
This script is executed via:
%run -i examples/script_dummy_spectrometer.py