K-shell ionization cross sections for elements Se to Pd: 0.4 to 2.0 MeV

$K$-shell ionization cross sections for protons over the energy range of 0.4 to 2.0 MeV have been measured on thin targets of the elements Se, Br, Rb, Sr, Y, Mo, and Pd. Total x-ray and ionization cross sections for the $K$-shell are reported. The experimental values of the ionization cross sections are compared to the nonrelativistic plane-wave Born approximation, the binary-encounter approximation, the constrained binary-encounter approximation, and the plane-wave Born approximation with corrections for Coulomb-deflection and binding-energy effects.