unusual background

[Natale Perchiazzi]

Dear All,
performing a scan of a Co compound, in capillary setup, with CuKa1 primary
monochromated radiation, PSD detector, I get a bkgd decreasing as usual
from 10 to 50�, but then constantly increasing from 50� up to my upper
scan limit (100�). I have no ready aexplanation for this, and your
suggestions will be welcome.
Best regards        Natale Perchiazzi