Current Acquisition from a High voltage sensor

Hello All,
I am currently working on a project where I would need to measure the current from a Channel Electron Multiplier(CEM) anode. The anode is at a high voltage (+3000V) and the current output is of the order of microamps. The frequency of operation of the CEM is in order of tens of KHz.

I propose to isolate the anode from the amplifier system using a high voltage capacitor and then have a transimpedence amplifier. Could anyone suggest what class of OpAMps should I be using for this purpose. Also is there any other technique to implement this functionality.

Regards
Avinash Srinivasan