$4.($a$)$ Table $1$ shows the electron binding energies in various materials, which are candidates for the anode of an X$-$ray tube. All values shown in Table $1$ are in units of eV $.$

Table $1$

To design an X$-$ray tube that generates a characteristic X$-$ray peak of about $17\mathrm{.}1$ keV in photon energy $($any photon energy between $17\mathrm{.}0$ keV and $17\mathrm{.}2$ keV is acceptable$),$

$($i$)$ which material should be used as the anode? Explain your answer in detail.

$($ii$)$ What is the minimum kinetic energy of the electrons bombarding the anode to excite the X$-$ray peak? Explain your answer in detail.