Sample Transmission Calculator Testing

Introduction

This is a manual testing guide for the Sample Transmission Calculator (Interfaces > General > Sample Transmission Calculator).

Basic Usage

  1. For the Input Wavelength Range at the top of the window select Single from Type dropdown box and set

  • Low=1.8

  • Width=1

  • High=7.8

  1. In sample details set

  • Chemical Formula = V

  • Mass Density = 6

  • Thickness = 0.5

  1. Click Calculate button in bottom right - it should produce the following

../../_images/SampleTransmissionCalculatorTest.png

  1. Select Number Density instead of Mass Density in the sample details and set Number Density = 0.072 (it should produce an near identical result with transmission ~0.65 at the lowest wavelength).

Multiple atoms in chemical formula

  1. In sample details set

  • Chemical Formula = C2 H4

  • Mass Density = 0.93

  • Thickness = 0.015

  1. Click Calculate - the transmission should be ~0.9 for all wavelengths (the cross-section is dominated by incoherent scattering rather than absorption - only the latter depends on wavelength).

  2. Set Chemical Formula = C4 H8 and click Calculate - the result should not change. This doubles the number of scatterers in a formula unit, but because the mass density is the same it halves the number of formula units in the sample volume.

  3. Select Number Density instead of Mass Density in the sample details and set Number Density = 0.12 (it should produce an near identical result with transmission ~0.9 at the lowest wavelength). This is because the units of Number Density are atoms/Ang^3 not formula units/Ang^3.

  4. Set Chemical Formula = C2 D4 and Calculate - the transmission should be ~1 (deuterium has a much smaller incoherent cross-section than hydrogen).

Validation of Single Wavelength Range

For each of the following instructions there should be a warning message in red at the bottom of the window.

  1. Try setting Low > High

  2. Try setting Width > (High - Low)

  3. Try setting Width = 0

It should not allow you to input the following in the spin-boxes (no warning will be printed).

  1. Negative numbers

  2. Punctuation

  3. Non-numeric characters (including punctuation)

If you delete the contents of a box and then click Calculate it will reset it with the previously entered values.

Multiple Wavelength Range

  1. For the Input Wavelength Range at the top of the window select Multiple from Type dropdown box

  2. In the Multiple edit box enter 1,1,3 and click Calculate

  3. Right-click on the transmission_ws workspace in the main workbench window and Show Data - you should see that there are 2 bins at wavelengths 1.5 Ang and 2.5 Ang

  4. In the Multiple edit box enter 1,1,3,0.5,4 and click Calculate - in the workspace data table you should see additional bins at 3.25 Ang and 3.75 Ang

  5. Repeat the validation tests in Validation of Single Wavelength Range

Chemical Formula Validation

The following should produce a warning at the bottom of the window and throw an error from CalculateSampleTransmission

  1. Set Chemical Formula = C2H4 (i.e. remove the space)

  2. Set Chemical Formula = Z

  3. Set Chemical Formula = 0

  4. Set Chemical Formula = *

  5. Set Chemical Formula = 2C 4H