Primary Reference Cell Calibrations

Primary reference cells are calibrated for in-house use and for use by other national laboratories to provide clients and partners with a path for traceability to standards.

Our laboratory is one of only four facilities in the world certified to calibrate reference cells in accordance with the World Photovoltaic Scale, and these measurements are accredited to International Organization for Standardization 17025 standards. We are the only laboratory certified to calibrate primary reference cells, secondary reference cells, secondary reference modules, cells, and modules.

Once we obtain a reference cell, we subject it to carefully devised calibration procedures that minimize errors from the temperature-dependent spectral correction.

Major Instrumentation for Primary Reference Cells Measurements


Typical Applications

Special Features

Light Source

Wavelength Range


Linearity test bed

Determines the linearity of the short-circuit current (Isc) versus the total irradiance (Etot); 0.01-sun - several suns

Agilent 6-1/2 digit multimeter; calibrated 10 ohms resistance; insensitive to the light spectra or spatial nonuniformity changing with irradiance

400-W incandescent lamp (x2)

280 to 1,900 nm

10 nm full width at half maximum

Eppley HF primary absolute-cavity radiometer

Total irradiance; outdoor; 5.0┬░ field of view

Calibration: Integrating hemisphere; calibrated at the World Radiation Center (Davos, Switzerland)


300 to 3,000 nm

>1 nm full width at half maximum

ASD Spec-Pro spectroradiometer

Spectral irradiance (extended using a comprehensive spectral model derived from Modtran); outdoor; 5.0┬░ field of view

VNIR: silicon photo-diode array (350 to 1000 nm)

SWIR1: InGaAs, photo-diode (1000 to 1830 nm)

SWIR2: InGaAs, photo-diode (1830 to 2500 nm)


350 to 2,500 nm

3 nm (VNIR) to 10 nm (SWIR) full width at half maximum