Surface Optics 410 DHR Infrared Reflectometer

Surface Optics 410 DHR Infrared Reflectometer Overview

The Surface Optics 410 DHR infrared reflectometer provides for portable, single-handed, quick and accurate measurements of directional hemispherical reflectance (DHR) in six infrared bands from 0.9 to 12μm. The 410 DHR employs a thermal source operated within an integrating sphere and measures hemispherical reflectance for two angles of illumination, 20° and 60° to the surface normal. From the measured reflectance, the in-band thermal emissivity of the surface is computed.

The Surface Optics 410 Family

The 410 DHR forms part of the 410 range of portable reflectometers and emissometers from Surface Optics Corporation (SOC) that are designed for reflectance, solar absorbance and thermal emissivity measurements in the visible to far infrared range. These modular devices feature interchangeable measurement heads and a common command module and generate data of comparable quality to much larger laboratory instruments.

The 410 DHR is a product of a collaboration between U.S. Naval Air Systems Command and SOC, with vital input from the Naval Research Lab (NRL) and National Institute of Standards and Technology (NIST). It was developed to answer a need for a portable instrument for verification of low observable stealth coatings in the field.

410 DHR Head for Infrared Directional Hemispherical Reflectance Measurements

The 410 DHR provides for measurements of directional hemispherical reflectance in six infrared bands from 0.9 to 12μm: 0.9-1.1; 1.9-2.4; 3.0-4.0; 3.0-5.0; 4.0-5.0; and 8.0-12.0μm. The 410 DHR employs a Kanthal thermal filament operating at approximately 1000°C within an integrating sphere for measurements in two geometries, 20°/H and 60°/H (directional illumination at 20° and 60° to the surface normal with hemispheric collection). From the measured reflectance, the 410 DHR computes the in-band emissivity of the surface. A grazing incidence version of the 410-DHR measurement head is available which illuminates the sample at 80° to the surface normal. Please note that the grazing incidence measurement head only operates at 80º.

Emissivity is that property of a material that determines its effectiveness at emitting thermal radiation, defined as the ratio of the quantity of thermal radiation emitted from a surface compared to the perfect black body radiator maintained at the same temperature, given by the Stefan-Boltzmann law. The measurement of emissivity is important for the calibration of pyranometers and thermal cameras which make non-contact temperature measurements.

Ergonomic Design

The lightweight pistol-grip design of the 410 DHR is modelled on a battery operated power tool. It is highly portable and allows single-handed use. Simply hold the sample port against the surface to be tested and press the trigger to take the measurement. View results immediately on the touch-screen display. Measurements can be taken on curved surfaces without special jigs or fixtures. The 410 Series measures the reflectance of flat, convex and concave surfaces (max. 150mm & 300mm radius, respectively) with a measurement spot of 12.7mm diameter.

An optional bench-top remote control unit (RCU) is available for the 410-series and operates by remote external control from a customer-supplied Windows PC. The bench-top configuration is ideal for routine QC applications and for installations where the 410 measurement head is mounted on a robot arm.