Ion Channeling Revisited

Track Date and time Hall Duration
Contributed Lectures Monday, 15. June 2015., 11:40 Mimoza II Hall 20’

Barney L. Doyle

Sandia National Laboratories, 87185-1056-Albuquerque, NM, USA

An MS Excel program has been written that calculates virtually all ion channeling parameters for any ion and energy on any cubic bcc, fcc or diamond lattice crystals for <uvw> axes and [hkl] planes up to (555). All of the tables and graphs in the three Ion Beam Analysis Handbooks that previously had to be manually looked up and read from were programed into Excel in handy lookup tables, or parameterized, for the case of the graphs, using rather simple yet accurate functions.

The program offers an extremely convenient way to calculate axial and planar half-angles, minimum yields, and the effects on half-angles of amorphous overlayers. The program can automatically generate standard stereographic projections of axial and planar channeling with the half-angles graphically represented to scale.  The program can also generate a new orthogonal projection of channeling that shows the channeling probability as a function of polar and azimuthal crystal orientation angles.  This projection is used to theoretically predict accidental (i.e. unintentional) channeling probabilities for randomly oriented crystals or crystallites. This becomes an important issue when simulating the creation by energetic neutrons of point displacement damage and extended defects using beams of ions.

The program is open source and can be downloaded from the website.