Pro Lite Technology

FFS-100 Forward Spectral Flux Standards

Labsphere FFS-100 Forward Flux Standard Lamp

The first commercially available standards of forward flux

Labsphere's FFS-100-400 and FFS-100-1000 are standards of forward spectral radiant flux which serve as NIST-traceable references used in the calibration of integrating sphere photometers and spectroradiometers as well as Labsphere's novel "Half Moon" integrating hemisphere systems.

An integrating sphere photometer is normally calibrated using a standard of spectral radiant flux (see: Labsphere SCL-series standard lamps). The lamp is placed in the centre of the sphere and radiates into 4π steradians. However, it is common for the forward or partial flux (that radiating into 2π steradians) from a collimated light source (for example, an LED downlighter) to be placed outside the sphere at the external source port. In this situation, measurement errors can be reduced by calibrating the sphere using a source of forward flux, thereby better matching the beam geometry of the standard to the device under test.

The FFS-100 forward flux standards are also used to impart a calibration upon Labsphere's integrating hemisphere photometers (the so-called "Half Moon" instruments). These instruments were specifically designed to measure the forward flux emitted by LED-based solid state lighting and cannot be calibrated using a conventional total flux standard.

The FFS-100 is available in two power levels, as a 400 lumen standard for calibrating 10, 12 and 20-inch spheres or hemispheres and as a 1,000 lumen standard for calibrating systems with a diameter of 40-inches or larger. Calibrations are performed in units of Watts per nm from 350 to 1050nm. The calibration certificate reports the total luminous flux in lumens and the calibration data is supplied on a CD-ROM in a format which is directly compatible with Labsphere's LightMtrX software.

The FFS-100 was designed for stability and reproducibility. Each standard has been carefully screened, seasoned, and calibrated in Labsphere's manufacturing facility under the guidelines recommended by the IESNA (Illuminating Engineering Society of North America). All of Labsphere’s standard lamps are first seasoned for 1% of their rated life and then screened for stability and repeatable performance before they are selected for calibration. The selected lamps are then calibrated directly to the NIST lumen, for a calibration result you can rely upon.

You will need to order a lamp power supply for your chosen FFS-100 separately. The Labsphere LPS-150-0416 is a precision, current regulated lamp power supply that provides the required 4.167 Amps to drive the FFS-100-400, while the LPS-150-0833 is used to drive the FFS-100-1000 at the rated 8.333 Amps. A 3m cable to connect the FFS-100 to the Labsphere power supply is included.

Specifications & Ordering Information




Product Code



Luminous Flux (lumens)



Operating Current (Amps)



Optional Power Supply



Recommended Sphere Size (inch)

ø10 & 20

ø40, 65 & 76

Recommended Half Moon (inch)

ø12 & 20



W/nm, 350 ... 1050nm, NIST traceable

Colour Temperature (Kelvin)

~ 2828

Rated LIfe (Hours)


Cable Length (m)


Dimensions (mm)


Weight (g)


Included in the Box

Calibration certificate
Calibration data on CD-ROM (formatted for LightMtrX software)
Power supply cable.


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