Experiments

For accessing data from the SPB experiment at European XFEL see SPB at EuXFEL.

Unfinished Feature

Note that everything mentioned on this site is still very preliminary and not fully fleshed out.

For developers

The purpose of experiments in xFrame is to provide access to XFEL scattering data. Conceptually an *experiment together with its settings file should contain all information necessary to create scattering patterns on a grid in reciprocal space for a given real experimental setup.
Such data includes, e.g.:

• X-ray wavelength, detector geometry, distance between sample and detector, detector mask, background to subtract, normalization range, …

A new experiment can be created as follows.

1. Choose a HOME_FOLDER as described in the Framework section.
2. Create a custom named folder

   HOME_PATH/experiments/my_experiment
   

3. place an experiments.py file in this folder with the following contents:

from xframe.interfaces import ExperimentWorkerInterface
from typing import Generator

class DataSelection:
    def __init__(_dict:dict):
        pass

class ExperimentWorker(ExperimentWorkerInterface):
    DataSelection = DataSelection
    def get_data(self,selection : DataSelection) -> Generator[int,None,None]:
        pass
    def get_reciprocal_pixel_grid(self) -> dict:
        pass
    def get_geometry(self) -> dict:
        pass
    def run(self):
        pass

DataSelection functions as a datastructure that contains all information needed to select a pice of scattering patterns (i.e. pulse_numbers, train_ids ....).
get_data takes a DataSelection object and returns a generator that retrieves chunks of processed scattering patterns.
get_reciprocal_pixel_grid returns the detector pixel coordinates in reciprocal space.
get_geometry returns real space information about the detector geometry.

Connection to projects
If an experiment has been given, either by calling

import xframe
xframe.select_experiment('my_experiment','default')
xframe.import_selected_experiment()

or by specifying the following command line arguments when a project is started,

$ xframe -e my_experiment -eopt default

one can access an instance of the above defined ExperimentWorker via

xframe.experiment

In the above expamle default is the name of a settings file placed in either of the following paths
HOME_PATH/settings/experiments/my_experiment/default.yaml
HOME_PATH/experiments/my_experiment/settings/default.yaml