1. What if you use a capillary, small specimen or transmission technique
“Gun” Mount
- Forensic Science
Courtesy Forensic Science
Laboratory - Germany
Film Mount
Courtesy Forensic Science
Laboratory - Germany
Transmission –
Combinatorial Analysis
- Courtesy Bruker-AXS

2. Glass Capillary Mount
Courtesy of PANalytical

3. Number of Particles - Reflection
Volume of sample in X-ray beam
V= (area of beam) (2x half-depth of penetration)
Assume area = 1cm x 1cm = 100mm2
t1/2 = 1/m,where m = linear absorption coefficient
mSiO2 = 97.6 cm-1 ~ 100 cm-1 = 10 mm-1
V = (100) (2) (10-1) mm3
= 20 mm3

4. Number of Particles – Capillary
Volume of sample in X-ray beam
V= (width of beam) (cross-sectional area of capillary)
For a 0.7 mm internal diameter capillary V= (width of beam) ( mm2) 
For a 1 cm-wide beam, V = 3.85 mm3
For a 1 mm-wide beam, V = mm3 !
However, capillary rotation brings many more particles into Bragg alignment

5. { What is usually going to cause you trouble?
Texture/orientation effects
- affects peak intensity
Sample displacement
- affects peak 2q position {
Bad particle statistics with thin films, small
specimens and capillaries
Well aligned capillary, film, or transmission system can
greatly reduce displacement errors. These systems frequently have
an alignment telescope or laser.

6. Cue for capillary sample preparation movies

7. Collimators, Slits, Mirrors, Capillaries Control Divergence
Tube
Tube
Glass Capillary Mount
Courtesy of PANalytical
Transmission –
Combinatorial Analysis
- Courtesy Bruker-AXS
Collimators, Slits, Mirrors, Capillaries
Control Divergence

8. Capillary Technique / Goniometer Head
Mark Tubes for μg Specimen :
Adjusting the Specimen
with the Crosshair and
the Laser Spot of the
Video Sample Alignment
System
In most cases the Mark tubes are fastened to a goniometer head.
This is screwed onto an additional Phi-circle, which is fastened to the XYZ-stage. The Phi – circle is a particularly attachment of our GADDS system.
The specimen is adjusted with the crosshair of the video microscope and the laser spot of the video sample alignment system to the instrument center.
Mark Tube on a
Goniometer Head
Additional Φ-Circle, Fastened to the XYZ - Stage

9. Fixed / Rotated Specimen
Sample Fixed:
Sample Rotated:
This image shows the data frame from a fixed and from a rotated specimen. Due to the non-isotropic specimen structure - large grains and preferred orientation- the intensity distribution along the Debye-Scherrer cones is inhomogenous in the case of the fixed specimen.
In order to obtain better statistics, we prepare most powder specimen with the capillary technique and we use the rotation mode with the phi-circle.
Courtesy Forensic Science
Laboratory - Germany

10. I = I e I = Transmitted Intensity I = Incident Intensity
- ut o
I = Transmitted Intensity
I = Incident Intensity
u = mass absorption coefficient
t = sample thickness o
0.1 cm or less thick, u most organics <10 cm-1

11. Test of influence of capillary diameter
Sample: tetracycline hydrochloride
Set of different capillaries:
0.3 mm, 0.5 mm, 0.7 mm, 1 mm, 2 mm
Goal: determine influence of capillary diameter on resolution and intensity
Data Courtesy
of PANalytical

12. Zoom-in of first peak Data Courtesy of PANalytical Counts 0.3 mm 40000
22500
10000
2500
Data Courtesy
of PANalytical
8.40
8.60
8.80 9
Position [°2Theta]

13. Optimum capillary diameter
Sample
Absorption
Insufficient
Volume of specimen
in the beam
Data Courtesy
of PANalytical

14. Comparison with parabolic mirror
Parallel Beam
Parabolic mirror
Data Courtesy
of PANalytical

15. Capillaries and Small Specimens
Accurate d-spacings
Intensity fluctuations
Increase collection area (2D detector)
Rotate specimen

16. Summary Experimental Goals and Specimen Parameters
Specimen for accurate d-spacing
Ideal: Thin specimen
Grain size ~ mm
Purpose: Low penetration
Sharp well-resolved peaks
Uses: Identification
Accurate cells

17. Summary Experimental Goals and Specimen Parameters
Specimen for accurate intensities
Ideal: Thick specimen
Grain size ~ 1mm
Purpose: Avoid preferred orientation
Produce smooth profiles
Uses: Quantification
Structure analysis

18. Summary Special specimen problems Solid specimens
Residual stresses may cause line shifts
Large solid specimens
Special supports and shielding
Thin layers
Grazing beam limits penetration
Special attachment collimators diffracted rays
Reactive specimens
Protect from atmosphere
Toxic specimens
Confine sample

19. Summary Special specimen problems Radioactive specimens
Confine sample and block radiation
Small specimens
Limited non-specimen scattering
Shaped particles
Deliberately orient particles
Dust specimens
Collect on filters