6.1

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SetGoniometer v1

../_images/SetGoniometer-v1_dlg.png

SetGoniometer dialog.

Summary

Define the goniometer motors used in an experiment by giving the axes and directions of rotations.

Properties

Name Direction Type Default Description
Workspace InOut Workspace Mandatory An workspace that will be modified with the new goniometer created.
Goniometers Input string None, Specify Individually Set the axes and motor names according to goniometers that we define in the code (Universal defined for SNS). Allowed values: [‘None, Specify Individually’, ‘Universal’]
Axis0 Input string   Axis0: name, x,y,z, 1/-1 (1 for ccw, -1 for cw rotation). A number of degrees can be used instead of name. Leave blank for no axis
Axis1 Input string   Axis1: name, x,y,z, 1/-1 (1 for ccw, -1 for cw rotation). A number of degrees can be used instead of name. Leave blank for no axis
Axis2 Input string   Axis2: name, x,y,z, 1/-1 (1 for ccw, -1 for cw rotation). A number of degrees can be used instead of name. Leave blank for no axis
Axis3 Input string   Axis3: name, x,y,z, 1/-1 (1 for ccw, -1 for cw rotation). A number of degrees can be used instead of name. Leave blank for no axis
Axis4 Input string   Axis4: name, x,y,z, 1/-1 (1 for ccw, -1 for cw rotation). A number of degrees can be used instead of name. Leave blank for no axis
Axis5 Input string   Axis5: name, x,y,z, 1/-1 (1 for ccw, -1 for cw rotation). A number of degrees can be used instead of name. Leave blank for no axis
Average Input boolean True Use the average value of the log, if false a separate goniometer will be created for each value in the logs

Description

Use this algorithm to define your goniometer. Enter each axis in the order of rotation, starting with the one farthest from the sample.

You may enter up to 6 axes, for which you must define (separated by commas):

  • The name of the axis, which MUST match the name in your sample logs. You can specify a number, and a log value will be created (GoniometerAxis?_FixedValue, where ? is the axis number)
  • The X, Y, Z components of the vector of the axis of rotation. Right-handed coordinates with +Z=beam direction; +Y=Vertically up (against gravity); +X to the left.
  • The sense of rotation as 1 or -1: 1 for counter-clockwise, -1 for clockwise rotation.

The run’s sample logs will be used in order to determine the actual angles of rotation: for example, if you have an axis called ‘phi’, then the time-average value of the log called ‘phi’ will be used as the rotation angle. Units are assumed to be degrees.

When the Average property is set to False then a separate goniometer will be created for each value in the log. When multiple log axes are defined they must have the same length and are assumed to be all the same time series.

The “Universal” goniometer at SNS is equivalent to Axis0 tied to the “omega” log pointing vertically upward, Axis1 tied to “chi” log, pointing along the beam, and Axis2 tied to “phi”, pointing vertically upward.

SetGoniometer(w,”Universal”) is the same as SetGoniometer(w,Axis0=”omega,0,1,0,1”,Axis1=”chi,0,0,1,1”,Axis2=”phi,0,1,0,1”)

Usage

wg = CreateSingleValuedWorkspace()
AddSampleLog(wg, "Motor1", "45.", "Number")
SetGoniometer(wg, Axis0="Motor1,0,1,0,1", Axis1="5,0,1,0,1")

print("Log values: {}".format(wg.getRun().keys()))
print("Goniometer angles:  {}".format(wg.getRun().getGoniometer().getEulerAngles('YZY')))
print("Clearing goniometer up")
SetGoniometer(wg)
print("Goniometer angles:  {}".format(wg.getRun().getGoniometer().getEulerAngles('YZY')    ))

Output:

Log values: ['Motor1', 'GoniometerAxis1_FixedValue']
Goniometer angles:  [50,0,0]
Clearing goniometer up
Goniometer angles:  [0,0,0]

Example - multiple goniometers - omega scan

ws = LoadILLDiffraction(Filename='ILL/D20/000017.nxs')
SetGoniometer(ws, Axis0='omega.position,0,1,0,1', Average=False)

print('Number of goniometers =', ws.run().getNumGoniometers())

for i in range(ws.run().getNumGoniometers()):
    print(f'{i} omega = {ws.run().getGoniometer(i).getEulerAngles("YZY")[0]:.1f}')

Output:

Number of goniometers = 21
0 omega = 1.0
1 omega = 1.2
2 omega = 1.4
3 omega = 1.6
4 omega = 1.8
5 omega = 2.0
6 omega = 2.2
7 omega = 2.4
8 omega = 2.6
9 omega = 2.8
10 omega = 3.0
11 omega = 3.2
12 omega = 3.4
13 omega = 3.6
14 omega = 3.8
15 omega = 4.0
16 omega = 4.2
17 omega = 4.4
18 omega = 4.6
19 omega = 4.8
20 omega = 5.0

Categories: AlgorithmIndex | Crystal\Goniometer

Source

C++ header: SetGoniometer.h (last modified: 2021-03-31)

C++ source: SetGoniometer.cpp (last modified: 2021-03-31)