1. Advanced Diffractometry at UWM
Robert Morien and Paul Lyman
Physics Department
University of Wisconsin-Milwaukee,
Milwaukee, WI 53211

2. X-ray diffractometry is used for:
• A non-destructive technique in analyzing semi-conductor
wafers and thin films for contamination and atomic
spacings
– Determination of substrate and film coherence
– Information concerning the stresses and strains
between lattice and film mismatches
• Primary method for determining molecular structure of
proteins, particularly DNA which was determined by use
of x-ray diffraction
• Analysis of crystalline phases present in any sample

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4. How are x-ray photons developed?
• X-rays are developed in an evacuated x-ray tube
• The tube is made of two electrodes, the anode and the
cathode
• The cathode is usually constructed of a tungsten filament
held at a high negative potential
• The anode is held at ground potential
• The cathode is heated producing thermionic emission
• Electrons are accelerated towards the anode ejecting
electrons of the anode material
• The hole of the ejected electron is filled by an outer shell
electron which creates x-ray radiation – the x-ray source
• Energy and thus the wavelength of the x-ray beam is
dependent upon material selected for the anode

5. The characteristic lines represent the energy and thus
wavelength which are characteristic of the emmited atom

6. Conventional Four-circle arrangement at UWM

7. Kappa diffractometer at UWM under construction

8. Using the Kappa Diffractometer with additional circle for
detector yields:
• Additional degree of
freedom to detect out-of-
surface plane scattering
vectors
• Can use additional
constraint to use grazing
incidence angles for
surface diffraction
• Kappa geometry allows
better access to sample
(NO OBSTRUCTING CHI
CIRCLE)

9. X-ray diffractometry techniques are continuing to advance. Each new
step leading to the solution of the phase problem.

10. Acknowledgements
• X-ray diffraction, a practical approach, C. Suryanarayana and M.
Grant Norton, Plenum Press, 1988
• Colorful discussions with Prof. Paul Lyman and H.T. Johnson-
Steigelman, University of WI-Milwaukee
• Pringle,Daniel; Shen Qun “New five-Circle kappa diffractometer for
reference beam diffraction studies” Journal of Applied
Crystalography 27 September 2002
http://staff.chess.cornell.edu/~shen/articles_published/Jac_2003_v.3
6_p29.pdf
• http://physics learning.colorodo.edu/PIRA/