The Stanford Research Systems QCM200 is a quartz crystal microbalance (QCM) controller that measures resonant frequency and resistance of 5 MHz AT-cut crystals for gravimetric analysis and dissipation monitoring. It detects mass changes from micrograms to fractions of a nanogram, including submonolayer quantities. The instrument correlates frequency shifts to deposited mass and resistance variations to viscosity and elasticity, enabling observation of phase transitions, swelling, and cross-linking. It operates reliably in high-glycerol solutions and heavy-load conditions, making it suitable for materials science, chemistry, and biology research.
Technical Specifications
Frequency Measurement
• Core frequency: 5 MHz, AT-cut quartz crystal
• Mass measurement range: Micrograms to fractions of a nanogram
• Detection limits: Submonolayers of atoms
• Frequency display resolution: 0.01 Hz (10 s gate), 0.1 Hz (1 s gate), 1.0 Hz (0.1 s gate)
• Selectable gate time: 0.1 s, 1 s, 10 s
• Internal timebase stability: < 4 × 10⁻⁹ Allan Variance (typical)
• Internal timebase accuracy: ±1.5 ppm
• Analog output (Δf): 0 to ±10 VDC, 20-bit resolution, user-selectable ranges ±200 kHz to ±2 kHz, 1 kΩ source impedance
• Frequency output: 5 MHz TTL square wave, 50 Ω source resistance
• External timebase input: 10 MHz, 1 kΩ impedance, 1 V peak-to-peak nominal
Resistance Measurement
• Measures series resonance resistance
• Display range: 0 to 5000 Ω
– Key Features
• Direct potentiostat interfacing via analog Δf output for EQCM applications
• External 10 MHz clock locking for ultra-stable measurements
• TTL frequency output compatible with external frequency counters
• User-configurable measurement gate times for resolution vs. speed tradeoffs
– Typical Applications
• Thin-film deposition monitoring and characterization
• Biomolecular interaction studies
• Viscous film and lossy media analysis
• Electrochemical QCM (EQCM) measurements
– Compatibility & Integration
Supplied with controller, crystal oscillator electronics, crystal holder, and three quartz crystals. Analog and digital outputs enable integration with potentiostats, frequency counters, and data acquisition systems.
