International
Tables for
Crystallography
Volume C
Mathematical, physical and chemical tables
Edited by E. Prince

International Tables for Crystallography (2006). Vol. C. ch. 4.3, p. 396

Figure 4.3.4.11 

C. Colliexa
[Figure 4.3.4.11]
Figure 4.3.4.11

Principle of the Castaing & Henry filter made from a magnetic prism and an electrostatic mirror. (R1, R2, and R3 are the real conjugate stigmatic points, and V1, V2, and V3 the virtual ones: the dispersion plane coincides with the R3 level and achromatic one with the V3 level.)