Tanaka Patterns

1
Tanaka Patterns

• Large-Angle Convergent-Beam Diffraction
• LACBED

2
The Tanaka Methods

• Traditional microscopy taught that the microscope
  should be focussed on the specimen or on the
  diffraction pattern in the back focal plane.
• Tanaka liberated us and gave rise to a family of
  new techniques by telling us to look in other
  places.

3
(No Transcript)
4
GaAs K. Christenson
5
GaAs 100 K. Christenson
6
M. Kaufman
7
Ni3Mo
8
Ni3Mo BF Tanaka pattern
9
(No Transcript)
10
Ni3Mo
11
Ni3Mo DF Tanaka pattern
12
Al layer on GaAs Tanaka Group
13
Defect Analysis

• Large-Angle Convergent-Beam patterns provide an
  alternative method of determining the Burgers
  vectors of dislocations. (And characterizing
  other defects.)
• The dislocations have to be well separated.

14
Fe,30Ni,19Cr 114 Cherns and Preston
15
Fe,30Ni,19Cr 114 Cherns and Preston
16
Fe,30Ni,19Cr 114 Cherns and Preston
17
Si Tanaka Group
18

• g.b n
• g is the reciprocal lattice vector
  corresponding to the diffracting planes
• b is the Burgers vector of the dislocation
• n is the number of lines of no contrast