Pressure equalized quartz crystal microbalance assembly

A pressure-equalization holder for a laboratory-scale material deposition system, wherein the pressure-equalization holder comprises:

• a first portion having a first process hole and a sensor cavity formed therein;
• a first seal having a second process hole formed therein and placed in the sensor cavity;
• a quartz crystal microbalance assembly (QCM assembly) placed in the sensor cavity to contact the first seal, wherein the first seal provides a first seal against a process side of a sensor holder of the QCM assembly;
• a second portion having a seal cavity formed therein and an inert fluid chamber formed therein, wherein the inert fluid chamber is fluidly connected to the seal cavity;
• and
• a second seal having an inert fluid hole formed therein and placed in the seal cavity, wherein the second seal provides a second seal against an inert side of the sensor holder of the QCM assembly.

A process for operating a laboratory-scale reactor coupled to a pressure-equalization holder for a quartz crystal microbalance assembly (QCM assembly), the process comprising:

• flowing a liquid in or through the laboratory-scale reactor at a process pressure;
• during flowing, contacting the liquid with a liquid-facing crystal surface of a crystal of the QCM assembly that is contained in the pressure-equalization holder;
• during flowing, contacting an inert fluid with an inert fluid-facing crystal surface of the crystal of the QCM assembly that is contained in the pressure-equalization holder, wherein the inert fluid is at the process pressure;
• and
• detecting a resonant frequency of the crystal of the QCM assembly based on contacting the liquid.