QCM Research has an extensive line of Cryogenic Surface Film Sensors (CQCMs) available.  Although these sensors were developed for use at very low temperatures (< 10 K) many customers have found that their very small size and excellent thermal properties make them ideal for higher temperature applications as well.  So well, in fact, that at the present the MK17 and MK18 CQCMs have become the most popular high temperature (> 77 K) QCMs available.

Our Cryogenic QCMs have a great degree of thermal isolation of the crystal pack, so that the case can be held at < 10 K while the crystals are heated, by means of an in-situ heater, to any desired temperature.  The upper limit for the crystal temperature has not been established but experience places an upper boundary in the 400 K range.  As in most of our QCMs, two crystals are used (sense and reference) in a crystal pack (gold plated OFHC copper), which is supported from the base by four heat-isolating struts.  This allows the heater (25 W wirewound precision resistor) to raise the temperature of the crystal pack using (at most) 3.6 watts of power.  This allows the investigator to raise the temperature from, say, 10 K, measure the mass change rate (frequency rate of change) as a function of the sense temperature and arrive by QCM thermogravimetric analysis (QTGA) 1, 2 at a knowledge of the sensor surface deposition composition.

The sense temperature is measured by either a cryogenic temperature silicon diode, or a Platinum Resistance Thermometer in a four-wire electrical circuit.

The CQCMs can easily be adapted for Space Flight and have flown in several different configurations.

MK16 Configuration

MK17 Configuration

MK18 Configuration

MK19 Configuration