• General Purpose Spheres:
  • Collection Sphere Systems
  • Transmittance/Reflectance Spheres
• Special Application Spheres:
  • Center Mount Integrating Spheres
  • Lamp Measurement/LED Cluster Measurements Spheres

Collection Sphere Systems

Avian Technologies collection spheres are designed for the general applications of photometry and radiometry. They may be used as cosine collectors, employing either their knife-edged port or another port with a transmissive diffuer as the collection port. With the addition of an internal source or using an external source, they can be used as uniform light sources that give a highly lambertain output.

Collection sphere systems include spun (6" or greater) or machined (diameter 4" or less) aluminum sphere with two ports at 90 degrees from each other along the equator of the sphere (drawing 1), a 1/4-20 mounting boss, and a mounting stand. The port sizes are 25 mm input and 12 mm detector on the 4",6", and 10" spheres and two 12 mm ports on the 2" (50 mm) sphere.

Coating Identifier

B: Avian-B coating: A barium sulfate based coating, similar to Munsell 6080 or Labsphere Spectraflect™. Primarily for laboratory usage. Effective wavelength range 300-1500nm
D: Avian-D Coating: A durable, high reflectance diffuse coating. Excellent for applications where durability or resistance to high humidity is required. Effective range 320- 1360 nm
F: Fluorilon-99W: reflectance material. This is not a coating but rather a machined thermoplastic material. Highly stable, both thermally and has great chemical resistance. Very high reflectance over entire effective range of <250-2500 nm
G: Avian Diffuse Gold Coating: Gold plated over a proprietary multi-layer metallic surface. Most effective in the 1.2-8u range (above 8u, it begins to lose its lambertain qualities) but special treatment can extend the effectiveness to >>25u. Reflectance of >94% over entire range.

See coatings and materials section for full technical information on Avian Technologies coatings and materials.

Reflectance/Transmittance Spheres

Reflectance/Transmittance spheres are designed for the purpose of measuring total hemispherical reflectance or total transmittance of solid materials located on the sphere wall. Typically, a spectrometer is used to illuminate the sample and non-filtered detector is used to collected the integrated flux. By using a 'white' light source and a photopically filter silicon detector, photometric measurements can be accomplished. Finally, if a broadband source is used to illuminate the sample, a dispersive device and a diode- or CCD- array can also provide spectral transmittance or reflectance measurements. The general purpose reflectance/transmittance spheres are configured to accommodate any of these types of measurement. The spheres are also configured to allow double-beam comparison type measurements, which are more accurate than simple 'substitution-sphere' measurements. (ref http://physics.nist.gov/Divisions/Div844/facilities/specphoto/references.html).

Systems include spun or machined aluminum sphere with four ports at 90 degrees from each other along the equator of the sphere (drawing 2), a 1/4-20 mounting boss, and a mounting stand. The ports include two 25 mm reflectance sample/reference ports, a 25 mm entrance/transmittance port, and a 10 mm= detector port. Detector port is screened from reflectance and transmittance port.

Lamp Measurement/LED Cluster Measurements Sphere

Avian Technologies now offers lamp measurement spheres in 20” (0.5 meter) and 40 “ (1.0 meter) sizes. These spheres are also useful for the measurement of LED clusters. The spheres are either bench-top (20”) or floor mounted with casters (40’).

Center Mount Sphere-Interior Access AT-INT-LLMS-200

Please contact us if you would like an interior sphere diagram.

Center Mount Sphere-Interior Access AT-INT-LLMS-400

Center mount post style sample stand with Teflon lamp holder with ‘banana’ type mounts (no wiring included).
2” fiber optic port, with fiber optic adapter with Fluorilon™ diffuser and port plug.
1” calibration lamp port with socket, 8-10W tungsten halogen lamp (uncalibrated-optionasl) and port plug. 1” measurement port. Multi- purpose baffle to block direct radiation of sample or calibration lamp from reaching the measurement port.
Coated with Avian-B (Barium sulfate) or Avian-D (Avian Technologies proprietary durable high reflectance) coating. Post and certain other components that see wear may be coated with Avian-D coating.
Optical design is identical to INT-LLMS-200 above except sphere is floor mounted with casters for portability.

Please contact us if you would like an interior sphere diagram.

AT-INT-FPMS-200 Flat Panel Display Metrology Sphere

20” Diameter reflectance measurement sphere for flat panel displays, with latches and a hinge mechanism for easy access to center mount, opening and closing, on a desktop-mounted stand with rubber feet.
The sphere includes a rotatable center mount, post style sample stand with 1/4-20 mounts on platform, adjustable holder for specimen displays up to 6” square in size. The center of rotation of platform is near front of platform. At the bottom of post is a cursor with angular designations for manual external adjustment of yaw angles.
Also included are:

Center Mount Integrating Spheres

By mounting samples in the center of an integrating sphere, spectral information on materials can be obtained that are not otherwise accessible. Positioning the sample at the center of the sphere, rather than tangent to the sphere's outer surface, offers certain advantages, including the ability to measure hemispherical reflectance as a function of incidence angle of illumination. This is a good predictor of the bi-directional reflectance distribution function (BRDF) of a material. In addition, using a fixed center mount, the transflectance (combined transmittance/ reflectance, a direct measurement of absorbance) of scattering materials can be determined, as well as turbidity.

Typically, center mounts are only used when sphere diameters are 6" or greater. If a smaller sphere is used, the size of the center mount itself becomes a large percentage of the total sphere wall area, thus causing what is known as substitution error, a systematic, predictable, non-random error inherent in single beam integrating spheres used to measure reflectance or transmittance.

One difficulty in making measurements using a center mount sphere is to shield the detector from the 'first bounce', which will have a higher luminance than later bounces, which have had a better chance to be integrated by the sphere coating. One solution to this problem, which is the solution Avian Technologies spheres employs, is to position the detector at the bottom of the sphere where it views the baffle on the underside of the sample holder. This geometry eliminates hot spots and is effective for reflectance, transmittance, and transflectance measurements.

Solid samples can be measured using either of two well-tested techniques. The Gier-Dunkle sphere uses a single-sided sample holder that swings out of the beam path for measurement of the reference baseline, then the sample is moved back into place at the desired angle for the measurement. Since the sample is in the sphere when the reference scan is being measured, the substitution error from interaction with the sample after the first strike is eliminated. The Gier-Dunkle sample holder can be modified to hold extremely thin, non-rigid samples by using clips rather than jaws to hold the sample.

The Edwards sphere geometry mounts the sample and reference back-to-back. While this configuration somewhat limits the size and shape of the sample and reference, the advantage lies in that the sample and reference can be measured at equivalent angles.

Liquid samples that scatter light are difficult to measure using a standard spectrophotometer, even when using an integrating sphere. Forward and side-scatter are not completely collected. By placing the sample cuvette in the center of the sphere, a complete collection of reflected and transmitted radiation can be obtained. When the directly transmitted component is eliminated by use of a light trap on the sphere wall reflectance port, a good measurement of both absolute absorbance and, with proper references, turbidity can be obtained. The total absorbance measurement is very useful in quantification of scattering species such as biological macromolecules, protein analysis, and measurement of phytoplankton concentration in seawater.

 

Variable Angle Reflectance/Transmittance Sphere

The sphere assembly consists of a 6" sphere with an entrance port, reflectance port at 180 degrees, a center mount for holding either rigid or non-rigid samples (three options on holder), and a detector port configured to view a baffle on the bottom of the sample holder. The center mount is calibrated in one degree increments to allow accurate positioning of the sample relative to the incident beam. The system includes one sphere and one center mount, detector port, reflectance port and port plug. Please specify sphere configuration and sample holder.

Additional center mounts are available for $1500 for Uv-Vis-NIR applications (Avian-D coated) or $2000.00 for mid-IR applications (diffuse gold coated).

(This sphere may also be configured for use with FT-IR spectrometers, using a gold coating)

Variable Angle R/T Sphere

Turbidity/Total Absorbance Center Mount Sphere

The sphere system includes a 6" diameter Avian-D coated sphere with an entrance port, specular subtraction/reflectance port at 180 degrees, a fixed center mount for holding a standard 1 cm path length cuvette at 0 degrees incidence to sample beam, and a detector port configured to view a baffle on the bottom of the sample holder. The sample holder is designed to minimize any absorption loss from scattered radiation.

Turbidity/Total Absorbance (Liquid) Sphere