CIRAS-4 Portable Photosynthesis System

The highly accurate CIRAS-4 Portable Photosynthesis System is a lightning-fast portable powerhouse that will elevate your research experience.

Its advanced software is exceptionally intuitive and customizable. You can manage environmental controls—as well as how you view your data—all from the touchscreen.

The CIRAS-4 is designed with the high-level field researcher in mind. Its small size makes it the most portable photosynthesis system of its kind, alleviating the need for assistance or tripods.

The innovative design of the CIRAS-4 utilizes its small system volume to ensure faster equilibration as well as the most rapid and accurate measurements available. Faster measurements allow the user to expand the parameters of their research and use their time and resources efficiently. Check out the size and weight of the CIRAS-4 console and leaf cuvettes and you will quickly discover why smaller and lighter is better.

The heart and soul of any photosynthesis system is the analyzer. Accurate, reliable, and stable measurement and control of CO2 and H2O are critical for high-level research. A “true differential analyzer”, the CIRAS-4 features 4 independent, non-dispersive gas analyzers for accurate, simultaneous measurement and control of both CO2 and H2O — a significant advantage over “gas switching” systems and a major requirement for most researchers. The analyzers act as absorptiometers measuring infrared absorption only. The temperature-controlled optical bench is pressure compensated ensuring the most accurate measurement of CO2 and H2O under changing ambient conditions.


CO2 Measurement Range

0 – 10000 µmol mol-1

(Optimized for 0-2000 µmol mol-1)

CO2 Accuracy

± 3 µmol mol-1 at 300 µmol mol-1

Within 1% of reading > 300 µmol mol-1

CO2 Precision 0.1 µmol mol-1
CO2 Control Range 0 – 2000 µmol mol-1
H2O Measurement Range 0 – 75 mmol mol-1
H2O Accuracy

± 0.08 mmol mol-1 up to 5 mmol mol-1

Within 1.5% of reading > 5 mmol mol-1

H2O Precision 0.01 mmol mol-1
H2O Control Range 0-Dewpoint or 0-100% Ambient
Pressure Range 55 – 115 kPa
Internal Memory 32 GB
Power Supply Two internal, rechargeable 7.2V Li-ion battery packs (Primary) provide up to 16 hours of continuous use. A third interchangeable battery pack (Reserve) further extends operation time. The power supply/charger can charge all three batteries simultaneously.


PLC4 Leaf Cuvettes

PAR Sensors (Internal)

2 silicon photodiode sensors

  • Range: 0 – 3000 µmol m-2 s-1
  • Precision: 1 µmol m-2 s-1
PAR Sensors (External)

Filtered silicon cell quantum sensor (cosine corrected).

  • Response: 400 – 700 nm
  • Range: 0 – 3000 µmol m-2 s-1
  • Accuracy: ± 5 µmol m-2 s-1
  • Precision: 1 µmol m-2 s-1
Air Temperature Sensor

Precision thermistor

  • Range: -10 to 50 °C
  • Accuracy: ± 0.5 °C at 25 °C
Cuvette Options
  • Universal
  • Broad/Narrow/Conifer