General Purpose Transmission Dip Probes

Our T300-RT and T200-RT Transmission Dip Probes couple to our spectrometers and light sources to measure absorbance and transmission in solutions. These probes are especially useful for embedding into process streams for in situ, real-time sample monitoring.

Theory of Operation

In transmission dip probes, light is transmitted from the illumination fiber through a plano-convex lens and through the sample compartment to a flat, second-surface mirror. The light reflects from this mirror and is focused by the lens onto the read fiber. The advantage of the transmission probe is its compact optical design, which fits into a 6.35-mm (1.4") OD stainless steel body, or ferrule.

The trade-offs with these probes are that they measure both transmitted light and backscattered light from the sample and have internal reflections that limit the dynamic range of the measurement. Still, at less than $1,000, transmission probes are a cost-effective option for many on-line and lab applications.

T300-RT Design

The T300-RT-UV-VIS Transmission Dip Probe consists of two 300-µm solarization-resistant optical fibers -- one illumination fiber and one read fiber -- in a 3.175-mm (1.8") OD stainless steel assembly that slides into a 127-mm long, 6.35-mm (1.4") OD stainless steel ferrule. Each leg of the probe assembly has an SMA 905 termination so that one leg can be attached to a light source and the other to a spectrometer.

TP300 Probe

The TP300-UV-VIS Probe is a chemically inert PEEK transmission probe that can be equipped with a tip (RT-PH) for mounting transmissive films in the optical path. Light is directed via one fiber through the mounted film to a mirror. Then light is redirected back through the film to a receive fiber that returns the light to the spectrometer. The sample is free to flow over the sides of the film. By using an RTP-2-10 (adjustable 2-10 mm) Transmission Tip, the TP300-UV-VIS can be used for routine transmission measurements.

T200-RT Design

The T200-RT-VIS-NIR Transmission Dip Probe has the same optical design as the T300-RT-UV-VIS, but is made with two 200-µm VIS-NIR optical fibers in its assembly.

Process Applications

Both probes fit into a standard 1.4" Swagelok fitting for installation into a pipe or reactor. Probe optics are mounted with an epoxy that offers superior chemical resistance to most solvents and can tolerate high temperatures.

Screw-on Tips: Choose Your Pathlength

Available separately are the screw-on, interchangeable probe tips necessary to use either probe. The RT-series tips come in pathlengths of 2 mm, 5 mm or 10 mm so that sampling setups can be configured for optically dense or dilute solutions.

Pricing