Thermoelectric Quartz Crystal Microbalances, or TQCMs, are thermoelectrically controlled QCMs.
They have an internal peltier heat exchanger which can either heat or cool the QCM to aid in both collecting condensables and then boiling them off
later.
They are available in four models: the MK10, MK20, MK24, and MK26. They utilize a Peltier element to heat or cool the crystals to provide full temperature control.
This feature makes the TQCMs very versatile.
The Mark 10 Thermoelectric Quartz Crystal Microbalance (MK10 TQCM) has become the defacto industry standard TQCM.
By cooling the 10 or 15 MHz quartz crystals, measurements can be made of the mass flow as it intercepts and is condensed at a specific temperature.
For space applications, the Sunwise crystal option has been added to minimize the solar thermal radiation input on the crystals.
The MK10 can be cooled by its own in-situ thermoelectric Peltier element without any external refrigerant, with a delta T of > 70°C when the heat sink is at ambient temperature.
This feature makes it particularly useful for material laboratories in the investigation of vacuum outgassing of spacecraft materials.
Monolayers of contamination are quite easily seen.
Additionally, a flight MK10 placed on a satellite will assure that the sensor crystal temperature for condensation of the particular contaminates will be
obtained.
Two MK10 sensors have been supplied, for example, for measuring the backflow of gasses onto a satellite from an ion rocket exhaust.
Baking the QCM at 40° to 50°C eliminates the accumulated contaminants.
The technique of slowly raising the temperature can be used for selectively identifying all of the fractionations that may be condensed.
If the MK10 is actually cooled externally at its heat sink plane of attachment, the lowest temperature at which it can operate is extended to approximately -200°C. MK10 TQCMs can be flight approved and have a successful flight history.
Custom orders are common and welcome. Call to discuss how we can build a MK10 TQCM system to meet your needs.
Diagrams
Specifications
| Sensor Output | 2K to ~250KHz | |
| Temperature Range | 100 to <-100°C (Active), 100 to -199°C w/o Temp Control (Passive) | |
| Signal Amplitude | >6 to 10Vpp | |
| Voltage Sensitivity | <23 Hz/V | |
| Output Impedance | 12KΩ | |
| Pressure Range | Ambient to Hard Vacuum | |
| Supply Voltage | 8 to 12 VDC (10V nominal) | |
| Continuous Power Requirement | ~120mW @ 10VDC w/o Peltier | |
| Peltier Heat Load | 6.25 watts maximum | |
| Weight | 120 grams | |
| Field of View | 74.5° Half Angle | |
| Crystal Frequencies | 10 MHz Crystals | 15 MHz Crystals |
| Mass Sensitivity | 2.26 x 108 (Hz/gm)cm2 | 5.09 x 108( Hz/gm)cm2 |
| Frequency Range | To ~ 100KHz | To ~ 150KHz |
| Mass Range | 4.42 x 10-4gm/cm2 | 2.95 x 10-4gm/cm2 |
MK-20
QCM
