Leading choice for ultra-high purity gas users

Detect gas quality upsets before they damage your process. Using Tiger Optics’ HALO OK oxygen analyzer, you can verify oxygen impurity levels with part-per-trillion accuracy, drift-free stability and instantaneous response. You’ll find our system exceptionally easy and fast to install, and effortless to maintain, with built-in zero verification. Its robust design—free of moving parts—results in an analyzer that has a high Mean Time Between Failure (MTBF) rate and a very low Cost of Ownership (CoO).

With its patented catalytic conversion technique, utilizing a minute amount of hydrogen to cleanly and safely convert oxygen to moisture, the OK offers a fully laser-based solution for Continuous Quality Control of your process. Based on powerful Cavity Ring-Down Spectroscopy, the HALO OK aligns with the SEMI F-112 standard for moisture dry-down characterization of gas systems. Pair the new HALO OK with our HALO KA for ppt-level moisture measurement to enjoy the many advantages of profit-boosting CRDS technology for both critical contaminants.

Designed for trace-level oxygen analysis, the HALO OK offers:

  • Industry-leading parts-per-trillion detection capability
  • Unprecedented speed of response
  • Wide dynamic range
  • Absolute measurement (freedom from need for calibration gases)
  • Low maintenance and cost of ownership
  • Compact, portable package, ideal for both fixed and mobile cart installation
  • Direct measurement in many matrices


  • Gas Quality Control
  • Gaseous CRMs & Calibration Gas Mixtures
  • High-Purity Gases & Systems
  • Hydrogen Fuel Cells
  • Research & Development

Learn More


Laboratory & Scientific

Stack, Process & CEMS

Detection Capability

Detection and Matrix Range LDL (3σ) Precision (1σ) @ zero
O2 in He 0 – 0.5 ppm 50 ppt 17 ppt
O2 in Ar 0 – 1 ppm 90 ppt 30 ppt
O2 in H2 0 – 2 ppm 150 ppt 50 ppt
O2 in N2 0 – 2.5 ppm 200 ppt 70 ppt
O2 in CO2§ 0 – 5 ppm 5000 ppt 300 ppt
§Special configuration required,
must be specified at time of order.


Operating range See Detection Capability table
Detection limit (LDL, 3σ/24h) See Detection Capability table
Sensitivity (3σ) See Detection Capability table
Precision (1σ, greater of) ± 0.75% or 1/3 of Sensitivity
Accuracy (greater of) ± 4% or 1/2 of LDL
Speed of response < 3 minutes to 95%
Environmental conditions 10°C to 40°C, 30% to 80% RH (non-condensing)
Storage temperature -10°C to 50°C
Gas Handling System and Conditions
Wetted materials 316L stainless steel, 10 Ra surface finish
Leak tested to 1 x 10-9 mbar l / sec
Gas connections 1/4” male VCR inlet and outlet
Sample inlet pressure 10 − 125 psig (1.7 − 9.6 bara)
Sample flow rate 0.5 – 1.8 slpm (gas dependent)
Sample gases Most inert matrices
Gas temperature Up to 60°C
H2 supply requirements* ~15 sccm, 20 − 125 psig
Dimensions, H x W x D
Standard sensor 8.73″ x 19.0″ x 23.6″ (222 mm x 483 mm x 599 mm)
Standard sensor 45 lbs (20.4 kg)
Alarm indicators 2 user programmable, 1 system fault, Form C relays
Power requirements 100 − 240 VAC, 50/60 Hz
Power consumption 450 Watts max.
Signal output Isolated 4−20 mA
User interfaces 5.7” LCD touchscreen, 10/100 Base-T Ethernet, RS-232
802.11g Wireless (optional), Modbus TCP (optional)
Certification CE Mark
U.S. Patent #7,277,177 • U.S. Patent # 7,255,836
*H2 supply (maximum 10 ppm H2O and O2
impurity) is required for sample conditioning
via catalytic conversion.
For enhanced safety, a mixture of 3% H2/97% N2
can be used as an alternative to pure H2.
LDL is dependent upon the quality of the sample
gas and the integrity of the sampling system.

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