First in Full Range PDA Spectrometer, Spectroradiometer and Spectrophotometer Systems
1 Canal Street  ◊  Unit B1
Lawrence, MA 01840  USA
Tel: 978 687-1833  ◊  Fax: 978 945-0372

Copyright © 2012 Spectral Evolution, Inc
The SR-3501 and SR-1901 spectroradiometers can classify continuous solar simulators to IEC
and ASTM standards. The SR-1901PT classifies pulsed solar simulators. The DARWin SP Data
Acquisition software provides reports for measuring the simulator's ability to meet class
Solar simulators are used in test and quality control for modules
and panels to measure their conversion of light to electric
current. There are two types of solar simulator: continuous and
pulsed. Continuous simulators provide a steady illumination for a
longer period of time; pulsed apply a flash type illumination of
shorter duration. Both types of simulators are classified as A, B,
or C simulators according to IEC and ASTM uniformity, and
temporal stability. It is important to ensure that your solar
simulator is meeting the requirments for its class as cells,
modules, and panels are typically categorized and priced
according to simulator data.

Measuring the uniformity, or more accurately non-uniformity of a
solar simulator ensures that the defined area covered by the
simulator is accurately and consistently illuminated. While solar
radiation is remarkably uniform, a simulator is hard pressed to
meet this consistency. ASTM standards provide the allowed
non-uniformity for each class of simulator as well as the
procedure for measuring non-uniformity.

Spectral Evolution provides spectroradiometers to measure
uniformity for both continuous and pulsed solar simulators. The
SR-3501 and SR-1901 can be equipped with a right angle diffuser
for uniformity measurements of continuous simulators, The      
SR-1901PT is specifically designed to measure pulsed simulators.
Uniformity testing can be done with one of  these
spectroradiometers and a right angle diffuser. The area covered
by the simulator should be divided into at least 36 equally sized
test positions. The right angle diffuser should be positioned at
the outer perimeter of test areas along each edge.
Non-uniformity of irradiance for Class A is 2%, Class B 5%, and
Class C 10%.
A Spectral Evolution spectroradiometer fitted with a right angle diffuser calibrated for irradiance was used to measure uniformity of a
commercial solar simulator. Measurements were taken by moving the right angle diffuser to different parts of the output light. The
DARWin software includes an energy integration utility (as seen above) that allows the user to integrate total energy detected over a
user-defined wavelength range.,
Measure Your Solar Simulator for Uniformity