Question

What is a wavelength of diagnostic X-rays ?

Answer 1

Generally, x-ray region is between 1 nm - 1 pm
(10^-9 m - 10^-12 m). It is a wide spectra. X-ray radiation
Emerges, When a electron is decelerated in close of an atom.

Then there are charasteric wavelengths when an outer electron
Transfers to inner core (auger electron). Perhaps you found a table of these charasteric avelengths somewhere.