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Gas sensing setup for sensor performance testing

Our lab features an in-house built setup for testing electrical gas sensors. The setup is structurally very simple and modular, yet very robust, allowing for reliable testing procedures.

Setup Highlights:

Setup Components:

Gas sensors testing is one of the applications where flow control is critical. 4 Alicat Scientific massflow controllers and valves regulate the gas flow to the test chamber. One of the fastest naturally responding mass flow controllers on the market today, Alicat devices have a standard accuracy at calibration after tare of ±(0.8% of Reading + 0.2% of Full Scale) and a high accuracy calibration after tare of ±(0.4% of Reading + 0.2% of Full Scale). Our setup also includes MFCs suitable for highly corrosive gases.

The test chamber is made from stainless steel and it can house one device at a time.With an approximate volume of 0.5dm3, it incorporates a heater within the testbed which allows the conductometric sensor to reach its operating temperature range while the ambient mixture of gases is kept at a controlled and constant temperature by circulating cold water through the walls of the chamber. The testbed’s heater is connected to an external controller. 

The sensing tests can be performed in a variety of pressure conditions inside the test chamber, ranging from atmospheric pressure to low pressures. Humidity inside the test chamber may be monitored. Controlled humidity conditions are foreseen to be implemented in the near future. 

Electrical signals (test currents or test voltages) are applied to the sensor employing the Keithley 2450 SourceMeter SMU Instrument connected to the test chamber’s designated fixtures. With a capability of more than 3000 readings/second, the same instrument also measures the sensor’s response signal in the presence of analyte gases. The Keithley 2450 Source Meter SMU is a high accuracy-high precision instrument, suitable for characterizing modern scaled semiconductors, nano-scale devices and materials, organic semiconductors, printed electronics and other small-geometry and low-power devices. It features a 0.012% basic measure accuracy with 6½-digit resolution. The new 20mV and 10nA source/measure ranges offer an enhanced sensitivity to this instrument.