Ni filter - before or after collimator?

[a***@gmail.com]

Howdy folks,
i am trying to filter my Cu x-ray source for the
CuKa line by using Ni filter. Is it more advantageous to put the Ni
filter before the collimator or after the collimator.

Thanks !!!!

[Joe Kelleher]

Post by a***@gmail.com
i am trying to filter my Cu x-ray source for the
CuKa line by using Ni filter. Is it more advantageous to put the Ni
filter before the collimator or after the collimator.

My first guess would be to put it before the collimator if you have a
choice, because as well as absorbing the Kb, some low angle transmission
diffraction might occur (maybe not very low angle, but never mind). The
collimator will discard these off-axis X-rays, and you won't have to worry
about them shining on the wrong part of your sample. If your diffracted beam
is also collimated, this is not really much of an issue though.

Joe