  Experiments related to X-ray optics carried out by A. H. Compton and his
collaborators during 1923-1927, led to the Nobel Prize winning discovery of
Compton Effect. Based on the critical analyses of these experimental
investigation results, we could infer a unique X-ray reflection property of
speculum metal that provided us the evidence for its reflectivity in the hard
X-ray region. In connection with this, we have studied in detail the
theoretical X-ray reflectivity of speculum metal in comparison with variety of
other mirror materials for different photon energies at various grazing angles
of incidence. Theoretical calculations of grazing incidence X-ray reflectivity
for these materials also verified well with other experimental data and
computer simulations. We have also calculated the minimum and critical angle
penetration depth of speculum metal with other mirror materials for different
photon energies. Furthermore, the reflectivity of speculum metal in different
regions of electromagnetic spectrum in association with its physical properties
is discussed. The analytical results obtained from these studies indicated that
the reflectivity of speculum metal in the X-ray region, especially in hard
X-ray region at small grazing angles is higher than that for commonly used high
density mirror materials.
