A refrigeration system includes a first portion having a primary loop and a secondary loop operably coupled by a first chiller, The primary loop circulates a refrigerant through the first chiller to provide cooling to a coolant in the secondary loop. The line sensors, the monitor sensors, and the control device are provided on a common circuit board. These dielectric reflectors are disposed in such a way as to allow selection of preferred low order modes and suppression of parasitic modes while allowing a high cavity Q factor for preferred modes.