Abstract: A fluidization measurement system for a gas phase reactor containing a fluidized bed includes a measurement probe coupled to a sidewall of the gas phase reactor. The measurement probe includes a support bar penetrating the sidewall and extending into the fluidized bed to a distance of at least 12% of a diameter of the gas phase reactor, and a plurality of sensors arranged along a length of the support bar to obtain measurements of at least one of temperature, pressure, and electrostatic charge at multiple points within the fluidized bed. A base plant control system is in communication with measurement probe to receive and process the measurements to determine real-time physical conditions and flow patterns of the fluidized bed.