Some Data:
<ISP 2,980 sec
It's pretty hard to find the acceleration voltage. Peak power is ~ 1 kW, and beam current ~ 130 mA, but some of the power is used for microwave pumping and ejecting a balancing ion stream to avoid charge build-up.
At face value, the maximum grid voltage would appear to be be 1 kW/130 mA i.e. ~ 7.5 kV