  It is shown that weakly interacting massive particles (WIMPs), which are
possible cold dark matter candidates, can be studied by exclusive measurements
of X-rays following WIMPs nuclear interactions. Inner-shell atomic electrons
are ionized through WIMP-nuclear interaction, and then mono-energetic X-rays
are emitted when they are filled by outer-shell electrons. The number of
inner-shell holes amounts to as large as one per five nuclear recoils for
K-shell and several per recoil for L-shell in the case of medium heavy target
nuclei interacting with 100-300 GeV WIMPs. Then the K and L X-ray peaks show up
in the 5-50 keV region. Consequently exclusive studies of the X-rays in
coincidence with the nuclear recoils and the ionization electrons are found to
provide excellent opportunities to detect WIMPs such as the Lightest Super
Symmetric Particles (LSP)
