Berkelium Ionization Energy

The Berkelium Ionization Energy is the energy required to remove from atom one mole of electrons with subsequent production of positively charged ion of Berkelium.
Bk -> Bk⁺ + e^-
This process can be repeated many times, but the energy cost is increased dramatically. The general equation for the Berkelium is:
Bk^N+ -> Bk^(N+1)+ + e^-

There is no data about Berkelium ionization energy