ADC programming in energia to handle 200khz signals coming from acoustic emission sensors

The G2553's ADC can record up to 200k samples per second. As described by the Nyquist-Shannon sampling theorem, this can handle only signals with a frequency of less than 100 kHz (higher frequencies can vanish due to aliasing).

How to setup the ADC is explained in the 2xx Family User's Guide. Did you read it?
And the example code package for the MSP430G2553 contains ADC examples.

If you want to digitize and show on a screen for human visual interpretation or dsp math, get a more powerful mcu.
Could you just measure phase-shift? sending the signal to both inputs of a highspeed XOR gate and a R/C filter,
if the signal is in perfect match you will get 0V out.
The more one pin is phase shifted (as little as few ns), the higher the voltage and that is something you could measure with msp430's A/D