ET-100 Emissometer

Total Hemispherical Emittance Measurements

The ET-100 measures directional reflectance from 1.5 to 21 μm and, based on those values, calculates directional and total hemispherical emissivity. The ET-100 emissometer conforms to ASTM E408, the standard test method for the determination of emittance using a portable instrument. In-band reflectance data for six discrete bands.

Datasheet

In-Band Reflectance & Emittance

1.5-2.0, 2.0-3.5, 3.0-4.0, 4.0-5.0, 5.0-10.5, 10.5-21.

ASTM Compliant

Compliant with ASTM E408.

Save Time

90 sec warm up, no equilibration
between measurements.

Easy to Use

Simply press port against sample and pull trigger.

Dual Angles of Incidence

Near normal 20° and near grazing 60° incident angles.

Room Temperature Samples

Calculate emissivity without heating sample.

ET-100 Applications

Characterizing materials for:

IR signature management

Low observable coatings

Radiative heat transfer

Emissivity for thermal modeling

Thermal camera calibration

Wafer fab hardware emissivity

Intuitive Software

The ET-100 touchscreen interface provides:

Temperature selection
Guided calibration
Sample labeling
Measurement data display
Sample type selection for emittance calculation

More Information

Measured Parameter	Directional hemispherical reflectance (DHR)
Method	Integrated total reflectance in a band for a given angle of incidence
Measured Value	Absolute reflectance (0-1)
Calculated Value	Directional thermal emissivity at 20º, directional thermal emissivity at 60º, hemispherical thermal emissivity
Wavelength Bands (microns)	1.5-2.0, 2.0-3.5, 3.0-4.0, 4.0-5.0, 5.0-10.5, 10.5-21
Angle of Incidence	20º & 60º from normal incidence
Calibration Coupon	Specular Gold
Accuracy	+/- .03
Repeatability	± .005 units
Beam Spot Size	0.50 inches
Measurement Time	10 sec
Sample Size & Geometry	Flat: ≥ 0.5 in. diameter Curved: 6 in. convex; 12 in. concave
Warm Up Time	90 seconds
Time Between Measurements	2 seconds
Sample Temperature	Ambient or heated/cooled to 0 – 100º C
Operating Temp	0º to 40º C
Storage Temp	-25º to 70ºC
Run Time	2 hours on one battery. Battery easily replaced with continuous operation after battery replacement.
Power Source	Rechargeable battery (standard environmentally friendly NiMH)
Battery Recharge Time	1 hour
IR Source	Kanthal filament operated at about 1,000ºC
Weight	4.7 lb
Form Factor	H 11.54”, L 9.04”, W 3.27” (29.31 cm x 22.96 cm x 9.44 cm)
Operator Interface	LCD graphics screen, 1/4 VGA, touch screen, software buttons; trigger switch in handle
Software Applications	Pass/fail can be incorporated, user set values
Diagnostics	On screen status and signals monitor. Signal values stored with data. Raw data collection and display.
Data Format	Data files can be opened and post processed with Excel or a text processor
Data Storage	Removable SanDisk (SD) card
ASTM Standard	E408
Export Control	ECCN #3A999.F

ET100 Datasheet

Emissometers Model Comparison

Standard ET100 Components

Command Module with safety strap
ET100 Measurement Head with port cap
Specular Gold Calibration coupon in storage container (Non-NIST traceable)
SecureDigital card reader on a USB cable
SecureDigital card for data storage, 4 GB
ET100 operating software
12 Volt battery cartridge – 2 batteries total
Battery charger
Pelican Case shipping/storage container
Accessories container
1-year warranty
Worldwide support

Optional ET100 Components

Benchtop Remote Control Unit – 220VAC
Benchtop Remote Control Unit – 120VAC
Specular Gold Calibration Coupon (NIST Traceable)
ET100 Reflectometer Maintenance and Calibration Plan (Non-NIST)
ET100 Reflectometer Maintenance and Calibration Plan (NIST)
ET100 Extended Warranty
SD Card for Extra Data Storage
Handheld Command Module – 220VAC

What is the difference in the emissivity measurements provided by the 410-DHR, ET10 and ET100?

All three models measure directional hemispherical reflectance (DHR). The 410-DHR and ET10 provide in-band emittance for thir spectral bands using the calculation of one minus reflectance, or E = 1 – DHR. The ET100 uses the DHR to provide in-band emittance values plus a single value for directional emittance at 20 degrees, directional emittance at 60 degrees, and total hemispherical emittance.

Is there a way to extrapolate higher temperature emissivity from room temperature measurements?

The basic property measured by the ET100 is reflectance. Since reflectance is a physical constant, temperature independent, it can be used to determine an accurate emissivity value if the interrogated surface does not undergo a physical or a chemical change between the measurement at ambient temperature and the high temperature. The ET100 measures emissivity of an object at ambient temperature, and the user sets in the instrument the desired higher temperature, and it will calculate emissivity for that temperature.

Why do I need to select if the sample is metal or dielectric?

The metal and dielectric look up tables store values of a correlation factor for a range of Directional Thermal Emissvity (DTE) 20°. This correlation factor defines the relationship between DTE20° and THE and it is different for metals versus dielectrics. DTE20° is measured and multiplied by the correct correlation factor to yield THE. DTE60° is not used in this calculation.

How is the Total Hemispherical Emissivity (THE) calculated?

The near normal directional emissivity values are used to derive total total hemispherical emissivity utilizing correlations published Siegel and Howell, Thermal Radiation Heat Transfer, Taylor and Francis, 1992. The ratio of total hemispherical emittance to near-normal directional thermal emittance is plotted as a function of near-normal directional thermal emittance. There is a curve for metals and a curve for dielectrics. These correlations are stored as tables in the ET100 software and used to calculate total hemispherical emittance from the measured near-normal directional thermal emittance. While the ET100 measures directional thermal emissivity at 20 and 60 degrees angle of incidence, only the DTE20° is used to calculate the total hemispherical emissivity.

Which test method from ASTM E408 applies to the ET100?

Test Method C.

Hatcher, N., Hwang, M., & Blank, R. (2024). Acktar Fractal Black™ as a Dual-Function Thermal-Optical Control Coating and Structural Primer. 2024 IEEE Aerospace Conference, 1-7.

Rønning, D., & Tang, Y. (2024). Irradiation resistance of thermo-optical properties of zirconium diboride by 3 MeV electrons. Frontiers in Space Technologies, 5, Article 1355258. https://doi.org/10.3389/frspt.2024.1355258

S. P. Sanaka, N. D. Mareedu and Y. Bonu, “Characterization of Sustainable Solar Absorbing Materials for Solar Thermal Applications,” 2024 International Conference on Computational Intelligence for Green and Sustainable Technologies (ICCIGST), Vijayawada, India, 2024, pp. 1-7, doi: 10.1109/ICCIGST60741.2024.10717528.

Related Products

Total Hemispherical Emittance Measurements

In-Band Reflectance & Emittance

ASTM Compliant

Save Time

Easy to Use

Dual Angles of Incidence

Room Temperature Samples

ET-100 Applications

Intuitive Software

More Information

Related Products

ET10 Emissometer

410-VIS-IR

Emissivity Measurements

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