Mark 18
Cryogenic Quartz Crystal Microbalances
As the name implies, the Cryogenic Quartz Crystal Microbalances or CQCMs have the ability to detect gasses or contaminates successfully below the temperatures of liquid Nitrogen to 10K or -262°C. Most have an internal heater and optional temperature sensor which can be used for molecular flux measurement of gasses to or from crystal surfaces.
As the name implies, the Cryogenic Quartz Crystal Microbalances or CQCMs have the ability to detect gasses or contaminates successfully below the temperatures of liquid Nitrogen to 10K or -262°C. Most have an internal heater and optional temperature sensor which can be used for molecular flux measurement of gasses to or from crystal surfaces.
Introducing
As the name implies, the Cryogenic Quartz Crystal Microbalances or CQCMs have the ability to detect gasses or contaminates successfully below the temperatures of liquid Nitrogen to 10K or -262°C. Most have an internal heater and optional temperature sensor which can be used for molecular flux measurement of gasses to or from crystal surfaces. The operator can set the heater to hold the crystals at temperatures below which the gasses condense in a vacuum environment. A piezoelectric quartz crystal will respond in a linear mass to frequency relationship as molecules condense on the sense crystal. The increased mass of the collected condensed gasses reduces the frequency at which the crystal resonates making it possible to calculate the amount or rate at which the gasses are collected. The electrical data from the piezoelectric crystal can be transmitted and is ideal for remote locations. During manufacturing, crystals can be cut to produce various crystal frequencies and can be ordered to increase molecular sensitivity or enhance mass measurements. After completing a test, the heater can then be used to boil off the condensed material on the crystal and testing can continue.
CQCMs are often used in vacuum chambers to investigate various aspects of outgassing from spacecraft surfaces. The crystals can be over-coated to record the erosion rate of a coating during Low Earth Orbit, or the erosion or deposition from ion thrusters. They have been used to monitor contaminants on telescope lenses and solar panels. Our LT (Low Temperature) line of CQCMs are eminently useful for liquid helium operation.
QCM Research offers four models of CQCMs: the MK16, MK17, MK18 and the MK19. CQCMs are similar but with differences in the mounting flange and cabling options. The MK19 is designed for situations where crystal temperature control is not desirable.
When utilizing QCMs in a vacuum chamber, commands and communication with the QCMs are possible with M2000 Control / Data Acquisition Unit. This is a complete hardware and software package that works with a host PC and controls the QCM(s) and records the testing in a graph and spreadsheet formats. For space flight our modular M3000 Controller is available. It also controls the QCMs and is integrated into the onboard computer system.
Every QCM is built to order and fully customized to your needs. All of our QCMs can be flight qualified and have flight history. Flight QCMs are customarily tested to your specifications and can be delivered with environmental testing completed.
Specifications
| Temperature Options | Standard Temperature | Low Temperature |
| Sensor Output | to 100KHz | to 100KHz |
| Temperature Range | -199 to 100°C | 10 to 400°K (-263 to 127°C) |
| Signal Amplitude | >6 to 10 Vp-p | 0.2 to 2.0 Vp-p |
| Voltage Sensitivity | <23 Hz/V | <23 Hz/V |
| Output Impedance | 12K Ohms | 13K to 27K Ohms |
| Pressure Range | Ambient to Hard Vacuum | Ambient to Hard Vacuum |
| Supply Voltage | 8 to 12 VDC (10 VDC nominal) | 8 to 12 VDC (10 VDC nominal) |
| Continuous Power | ~120mW @10VDC | 2.45mW @10VDC |
| Power/In-Situ Heater | <5.8W | <5.8W |
| Temperature Sensor | Included | Included |
| Weight | 28.9 grams | 28.9 grams |
| Field of view | 71.5° Half Angle | 71.5° 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 |
Warranty
QCM Research products are warranted for a period of ONE YEAR from the date of receipt by the purchaser against defects in materials and workmanship. QCM Research expressly limits its liability to the replacement or repair of the article furnished (this choice is at the sole discretion of QCM Research). This warranty does not apply to products that have been disassembled, modified or subjected to conditions exceeding the applicable product specifications and ratings. In the event of any of the foregoing, the warranty will be void. Failure due to excessive contamination is not covered under warranty, whether from proper or improper use. QCM Research disclaims any warranty other than as specifically set forth herein, and may discontinue models or alter their specifications without notice.
