ASTM G130-12(2020)

Standard Test Method for Calibration of Narrow- and Broad-Band Ultraviolet Radiometers Using a Spectroradiometer

SIGNIFICANCE AND USE
4.1 This test method represents the preferable means for calibrating both narrow-band and broad-band ultraviolet radiometers. Calibration of narrow- and broad-band ultraviolet radiometers involving direct measurement of a standard source of spectral irradiance is an alternative method for calibrating ultraviolet radiometers. This approach is valid only if corrections for the spectral response of the instrument and the spectral mismatch between the calibration spectral distribution and the target spectral distribution can be computed. See Test Method E973 for a description of the spectral mismatch calculation.  
4.2 The accuracy of this calibration technique is dependent on the condition of the light source (for example, cloudy skies, polluted skies, aged lamps, defective luminaires, etc.), and on source alignment, source to receptor distance, and source power regulation.
Note 5: It is conceivable that a radiometer might be calibrated against a light source that represents an arbitrarily chosen degree of aging for its class in order to present to both the test and reference radiometers a spectrum that is most typical for the type.  
4.3 Spectroradiometric measurements performed using either an integrating sphere or a cosine receptor (such as a shaped PTFE3, or Al2O3 diffuser plate) provide a measurement of hemispherical spectral irradiance in the plane of the sphere's entrance port. As such, the aspect of the receptor plane relative to the reference light source must be defined (azimuth and tilt from the horizontal for solar measurements, normal incidence with respect to the beam component of sunlight, or normal incidence and the geometrical aspect with respect to an artificial light source, or array). It is important that the geometrical aspect between the plane of the spectroradiometer's source optics and that of the radiometer being calibrated be as nearly identical as possible.
Note 6: When measuring the hemispherical spectral energy distribution of an arra...
SCOPE
1.1 This test method covers the calibration of ultraviolet light-measuring radiometers possessing either narrow- or broad-band spectral response distributions using either a scanning or a linear-diode-array spectroradiometer as the primary reference instrument. For transfer of calibration from radiometers calibrated by this test method to other instruments, Test Method E824 should be used.  
Note 1: Special precautions must be taken when a diode-array spectroradiometer is employed in the calibration of filter radiometers having spectral response distributions below 320-nm wavelength. Such precautions are described in detail in subsequent sections of this test method.  
1.2 This test method is limited to calibrations of radiometers against light sources that the radiometers will be used to measure during field use.  
Note 2: For example, an ultraviolet radiometer calibrated against natural sunlight cannot be employed to measure the total ultraviolet irradiance of a fluorescent ultraviolet lamp.  
1.3 Calibrations performed using this test method may be against natural sunlight, Xenon-arc burners, metal halide burners, tungsten and tungsten-halogen lamps, fluorescent lamps, etc.  
1.4 Radiometers that may be calibrated by this test method include narrow-, broad-, and wide-band ultraviolet radiometers, and narrow-, broad, and wide-band visible-region-only radiometers, or radiometers having wavelength response distributions that fall into both the ultraviolet and visible regions.  
Note 3: For purposes of this test method, narrow-band radiometers are those with Δλ ≤ 20 nm, broad-band radiometers are those with 20 nm ≤Δλ ≤ 70 nm, and wide-band radiometers are those with Δλ ≥ 70 nm.
Note 4: For purposes of this test method, the ultraviolet region is defined as the region from 285 to 400-nm wavelength, and the visible region is defined as the region from 400 to 750-nm wavelength. The ultraviolet region is further def...

General Information

• Status: Published
• Publication Date: 31-May-2020
• ICS: 17.180.20 - Colours and measurement of light
• Technical Committee: G03 - Weathering and Durability
• Drafting Committee: G03.09 - Radiometry

Relations

• Replaces: ASTM G130-12 - Standard Test Method for Calibration of Narrow- and Broad-Band Ultraviolet Radiometers Using a Spectroradiometer
• Effective Date: 01-Jun-2020
• Refers: ASTM G138-12(2020)e1 - Standard Test Method for Calibration of a Spectroradiometer Using a Standard Source of Irradiance
• Effective Date: 01-Jun-2020
• Refers: ASTM E973-16(2020) - Standard Test Method for Determination of the Spectral Mismatch Parameter Between a Photovoltaic Device and a Photovoltaic Reference Cell
• Effective Date: 01-Jun-2020
• Refers: ASTM E824-10(2018)e1 - Standard Test Method for Transfer of Calibration From Reference to Field Radiometers
• Effective Date: 15-Apr-2018
• Refers: ASTM E973-16 - Standard Test Method for Determination of the Spectral Mismatch Parameter Between a Photovoltaic Device and a Photovoltaic Reference Cell
• Effective Date: 01-Jul-2016
• Refers: ASTM E973-15 - Standard Test Method for Determination of the Spectral Mismatch Parameter Between a Photovoltaic Device and a Photovoltaic Reference Cell
• Effective Date: 01-Dec-2015
• Refers: ASTM E973-10(2015) - Standard Test Method for Determination of the Spectral Mismatch Parameter Between a Photovoltaic Device and a Photovoltaic Reference Cell
• Effective Date: 01-Mar-2015
• Refers: ASTM E772-13 - Standard Terminology of Solar Energy Conversion
• Effective Date: 01-Sep-2013
• Refers: ASTM G138-12 - Standard Test Method for Calibration of a Spectroradiometer Using a Standard Source of Irradiance
• Effective Date: 01-Jun-2012
• Refers: ASTM E772-11 - Standard Terminology of Solar Energy Conversion
• Effective Date: 01-Sep-2011
• Refers: ASTM E824-10 - Standard Test Method for Transfer of Calibration From Reference to Field Radiometers
• Effective Date: 01-Dec-2010
• Refers: ASTM E973-10 - Standard Test Method for Determination of the Spectral Mismatch Parameter Between a Photovoltaic Device and a Photovoltaic Reference Cell
• Effective Date: 01-Jun-2010
• Refers: ASTM G138-06 - Standard Test Method for Calibration of a Spectroradiometer Using a Standard Source of Irradiance
• Effective Date: 01-Jun-2006
• Refers: ASTM E824-05 - Standard Test Method for Transfer of Calibration From Reference to Field Radiometers
• Effective Date: 01-Oct-2005
• Refers: ASTM E973-05a - Standard Test Method for Determination of the Spectral Mismatch Parameter Between a Photovoltaic Device and a Photovoltaic Reference Cell
• Effective Date: 01-Sep-2005

Overview

ASTM G130-12(2020) specifies the standard test method for calibrating narrow- and broad-band ultraviolet radiometers using a spectroradiometer. Published by ASTM International, this standard provides a preferred calibration approach for UV radiometers, ensuring measurement accuracy and consistency across a variety of applications where precise UV irradiance is critical. The test method covers calibration using either scanning or linear-diode-array spectroradiometers as the primary reference instruments and outlines requirements for measurement traceability, uncertainty estimation, and instrument configuration.

Key Topics

• Calibration of UV Radiometers: The standard defines procedures for calibrating radiometers with narrow- and broad-band spectral response, typically used to measure ultraviolet and visible light.
• Types of Radiometers Covered: Applicable to narrow-band (Δλ ≤ 20 nm), broad-band (20 nm ≤ Δλ ≤ 70 nm), and wide-band (Δλ ≥ 70 nm) radiometers, in both the UV (285–400 nm) and visible (400–750 nm) ranges.
• Traceability and Accuracy: Emphasizes traceability to national metrological laboratories, intercomparisons of standards, and use of standard lamps or sunlight as calibration sources.
• Spectroradiometric Measurement: Calibrations may employ integrating spheres or cosine receptors for accurate hemispherical spectral irradiance measurements.
• Environmental and Setup Factors: Considers factors affecting calibration reliability, such as light source condition, alignment, source-to-receptor distance, and temperature stability of equipment.

Applications

• Weathering and Durability Testing: Accurate calibration of UV radiometers is essential for outdoor weathering of materials and indoor accelerated exposure testing using artificial light sources.
• Solar and Environmental Monitoring: Radiometers calibrated per ASTM G130-12(2020) are used in assessments of solar UV exposure, climate studies, and research on changes in solar UV reaching the Earth's surface.
• Laboratory and Field Instrumentation: The standard ensures that both laboratory reference instruments and field-deployed radiometers deliver reliable and comparable measurements.
• Quality Assurance in UV Measurement: Following this method supports quality assurance for any application requiring validated and traceable measurement of UV irradiance, including compliance with regulatory and industrial requirements.

Related Standards

• ASTM E824: Transfer of calibration from reference to field radiometers.
• ASTM E973: Determination of the spectral mismatch parameter between a device and its reference.
• ASTM E772: Terminology of solar energy conversion.
• ASTM G138: Calibration of spectroradiometers using standard sources of irradiance.
• CIE Publication No. 63: Spectroradiometric measurement of light sources.

Practical Value

Organizations relying on precise UV measurements benefit from implementing the ASTM G130-12(2020) standard by achieving:

• Consistent Calibration Procedures ensuring UV radiometer accuracy across different devices and test setups.
• Improved Measurement Comparability through demonstrated traceability and reduced measurement uncertainty.
• Optimized Instrument Performance for specialized UV-A and UV-B measurement applications in various environmental and industrial contexts.
• Regulatory Compliance for laboratories and manufacturers seeking recognized standards for radiometric calibrations.

Adhering to ASTM G130-12(2020) enhances overall confidence and reliability in UV radiometric data, supporting research, quality testing, and environmental monitoring programs.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: G130 − 12 (Reapproved 2020)
Standard Test Method for
Calibration of Narrow- and Broad-Band Ultraviolet
Radiometers Using a Spectroradiometer
This standard is issued under the fixed designation G130; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Accurateandprecisemeasurementsofultravioletirradiancearerequiredinthedeterminationofthe
radiant exposure of both total and selected narrow bands of ultraviolet radiation for the determination
of exposure levels in (1) outdoor weathering of materials, (2) indoor accelerated exposure testing of
materialsusingmanufacturedlightsources,and(3)UV-AandUV-Bultravioletradiationintermsboth
of the assessment of climatic parameters and the changes that may be taking place in the solar
ultraviolet radiation reaching earth.
Although meteorological measurements usually require calibration of pyranometers and radiom-
eters oriented with axis vertical, applications associated with materials testing require an assessment
of the calibration accuracy at orientations with the axis horizontal (usually associated with testing in
indoor exposure cabinets) or with the axis at angles typically up to 45° or greater from the horizontal
(for outdoor exposure testing). These calibrations also require that deviations from the cosine law, tilt
effects, and temperature sensitivity be either known and documented for the instrument model or
determined on individual instruments.
This test method requires calibrations traceable to primary reference standards maintained by a
national metrological laboratory that has participated in intercomparisons of standards of spectral
irradiance.
NOTE 2—For example, an ultraviolet radiometer calibrated against
1. Scope
natural sunlight cannot be employed to measure the total ultraviolet
1.1 This test method covers the calibration of ultraviolet
irradiance of a fluorescent ultraviolet lamp.
light-measuring radiometers possessing either narrow- or
1.3 Calibrations performed using this test method may be
broad-band spectral response distributions using either a scan-
against natural sunlight, Xenon-arc burners, metal halide
ning or a linear-diode-array spectroradiometer as the primary
burners, tungsten and tungsten-halogen lamps, fluorescent
reference instrument. For transfer of calibration from radiom-
lamps, etc.
eters calibrated by this test method to other instruments, Test
Method E824 should be used.
1.4 Radiometers that may be calibrated by this test method
include narrow-, broad-, and wide-band ultraviolet
NOTE 1—Special precautions must be taken when a diode-array
spectroradiometer is employed in the calibration of filter radiometers radiometers, and narrow-, broad, and wide-band visible-
having spectral response distributions below 320-nm wavelength. Such
region-only radiometers, or radiometers having wavelength
precautions are described in detail in subsequent sections of this test
response distributions that fall into both the ultraviolet and
method.
visible regions.
1.2 Thistestmethodislimitedtocalibrationsofradiometers
NOTE3—Forpurposesofthistestmethod,narrow-bandradiometersare
against light sources that the radiometers will be used to
those with∆λ≤ 20 nm, broad-band radiometers are those with 20 nm≤∆λ
measure during field use.
≤ 70 nm, and wide-band radiometers are those with ∆λ ≥ 70 nm.
1 NOTE 4—For purposes of this test method, the ultraviolet region is
This test method is under the jurisdiction of ASTM Committee G03 on
defined as the region from 285 to 400-nm wavelength, and the visible
Weathering and Durability and is the direct responsibility of Subcommittee G03.09
region is defined as the region from 400 to 750-nm wavelength. The
on Radiometry.
ultraviolet region is further defined as being either UV-Awith radiation of
CurrenteditionapprovedJune1,2020.PublishedJuly2020.Originallyapproved
wavelengths from 315 to 400 nm, or UV-B with radiation from 285 to
in 1995. Last previous edition approved in 2012 as G130 – 12. DOI: 10.1520/
315-nm wavelength.
G0130-12R20.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G130 − 12 (2020)
1.5 This standard does not purport to address all of the element (prism or grating), and uses either a single, or several
safety concerns, if any, associated with its use. It is the interchangeable, detector(s) mounted at an exit slit. The detec-
responsibility of the user of this standard to establish appro- tor is presented with dispersed light by sweeping the spectrum
priate safety, health, and environmental practices and deter- across the slit to illuminate the detector with a succession of
mine the applicability of regulatory limitations prior to use. different very narrow wavelength light distributions. The
1.6 This international standard was developed in accor- detector may be either a photomultiplier tube (PMT) or silicon
dance with internationally recognized principles on standard- photodiode(visible),oranultraviolet-enhancedPMTorsilicon
ization established in the Decision on Principles for the photodiode (ultraviolet and visible), or a lead sulfide cell or
Development of International Standards, Guides and Recom- other solid state detector (near infrared), etc. The dispersed
mendations issued by the World Trade Organization Technical spectrum is swept across the exit slit using a mechanical stage
Barriers to Trade (TBT) Committee. that rotates the element, usually under the control of an
external microprocessor or computer.
2. Referenced Documents
3.1.7 spectroradiometer—a radiometer consisting of a
2.1 ASTM Standards:
monochromator with special acceptance optics mounted to the
E772 Terminology of Solar Energy Conversion
entrance aperture and a detector mounted to the exit aperture,
E824 Test Method for Transfer of Calibration From Refer-
usually provided with electronic or computer encoding of
ence to Field Radiometers
wavelength and radiometric intensity. The monochromator of
E973 Test Method for Determination of the Spectral Mis-
suchinstrumentsiseitherofthelineardiode(oftencalleddiode
match Parameter Between a Photovoltaic Device and a
array) or the scanning type.
Photovoltaic Reference Cell
3.1.8 wide-band radiometer—a relative term generally ap-
G138 Test Method for Calibration of a Spectroradiometer
plied to radiometers with combinations of cut-off and cut-on
Using a Standard Source of Irradiance
filters with FWHM greater than 70 nm.
2.2 Other Documents: CIE Publication No. 63 The Spec-
3.2 For other terms relating to this test method, see Termi-
trodiometric Measurement of Light Sources
nology E772.
3. Terminology
4. Significance and Use
3.1 Definitions:
4.1 This test method represents the preferable means for
3.1.1 broad-band radiometer—radiometerric detectors with
calibrating both narrow-band and broad-band ultraviolet radi-
interference filters or cut-on/cut-off filter pairs having a
ometers. Calibration of narrow- and broad-band ultraviolet
FWHM between 20 and 70 nm and with tolerances in center
radiometers involving direct measurement of a standard source
(peak) wavelength and FWHM no greater than 62 nm.
of spectral irradiance is an alternative method for calibrating
3.1.2 diode array detector—a detector with from a number
ultraviolet radiometers. This approach is valid only if correc-
of silicon photodiodes affixed side-by-side in a linear array and
tions for the spectral response of the instrument and the
mounted in the focal plane of the exit slit of a monochromator.
spectral mismatch between the calibration spectral distribution
and the target spectral distribution can be computed. See Test
3.1.3 full width at half maximum (FWHM)—in a bandpass
filter, the interval between wavelengths at which transmittance Method E973 for a description of the spectral mismatch
calculation.
is 50 % of the peak, frequently referred to as bandwidth.
3.1.4 narrow-band radiometer—a relative term generally 4.2 The accuracy of this calibration technique is dependent
applied to radiometers with interference filters with FWHM on the condition of the light source (for example, cloudy skies,
≤20 nm and with tolerances in center (peak) wavelength and polluted skies, aged lamps, defective luminaires, etc.), and on
FWHM no greater than6 2 nm. source alignment, source to receptor distance, and source
power regulation.
3.1.5 National Metrological Institution (NMI)—A nation‘s
internationally recognized standardization laboratory.
NOTE 5—It is conceivable that a radiometer might be calibrated against
3.1.5.1 Discussion—The International Bureau of Weights a light source that represents an arbitrarily chosen degree of aging for its
class in order to present to both the test and reference radiometers a
andMeasurements(abbreviationBIPMfromtheFrenchterms)
spectrum that is most typical for the type.
establishes the recognition through Mutual RecognitionAgree-
ments. See http://www.bipm.org/en/cipm-mra. The NMI for 4.3 Spectroradiometric measurements performed using ei-
theranintegratingsphereoracosinereceptor(suchasashaped
the United States of America is the National Institute for
Standards and Technology (NIST). PTFE,orAl O diffuser plate) provide a measurement of
2 3
hemispherical spectral irradiance in the plane of the sphere’s
3.1.6 scanning monochromator—an instrument for isolating
entrance port.As such, the aspect of the receptor plane relative
narrow bands of wavelength of light that admits broadband
to the reference light source must be defined (azimuth and tilt
light through an entrance slit, directs the light to a dispersive
from the horizontal for solar measurements, normal incidence
with respect to the beam component of sunlight, or normal
For referenced ASTM standards, visit the ASTM website, www.astm.org, or incidence and the geometrical aspect with respect to an
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. Polytetrafluoroethylene
G130 − 12 (2020)
artificial light source, or array). It is important that the surement of a transfer standard lamp generated by comparison
geometrical aspect between the plane of the spectroradiom- with a primary standard of spectral irradiance lamp.The
eter’s source optics and that of the radiometer being calibrated traceability of the lamp calibration source and attendant
be as nearly identical as possible. uncertainty shall be reported.
5.1.2 If a linear diode-array spectroradiometer is used as the
NOTE 6—When measuring the hemispherical spectral energy distribu-
reference, it shall possess focusing optics internal to the
tion of an array of light sources (for lamps), normal incidence is defined
by the condition obtained when the plane of the receiver aperture is monochromator and a linear diode array detector with a
parallel to the plane of the lamp, or burner, emitting area.
sufficient number of diodes that, together, result in a resolving
power of 1 nm or less. The monochromator’s dispersive
4.4 Calibration measurements performed using a spectrora-
element shall be a holographic grating, and the spectroradiom-
diometer equipped with a pyrheliometer-comparison tube (a
eter’s acceptance optics shall consist of either an integrating
sky-occluding tube), regardless of whether affixed directly to
sphere with appropriately sized and oriented light entrance
the monochromator’s entrance slit, to the end of a fiber optic
port, or a shaped translucent diffuser plate whose deviation
bundle, or to the aperture of an integrating sphere, shall not be
from true cosine response is small and known. A further
performed unless the radiometer being calibrated is configured
requirement is that the stray light rejection be determined for
as a pyrheliometer (possesses a view-limiting device having
the approximate optical constants of the spectroradiometer’s any diode-array spectroradiometers used to perform this test
method and that it be 10 or greater in the spectral region for
pyrheliometer-comparison tube).
which calibration is required.
4.5 Spectroradiometric measurements performed using
5.1.2.1 Adiode-array spectroradiometer shall not be used as
source optics other than the integrating sphere or the “stan-
the reference instrument for ultraviolet wavelengths shorter
dard” pyrheliometer comparison tube, shall be agreed upon in
than 300-nm wavelength. Further, when used in the wave-
advance between all involved parties.
length region between 300 and 320-nm wavelength, evidence
4.6 Calibration measurements that meet the requirements of
shall be presented with the calibration reports, or certificates,
this test method are traceable to a national metrological
showing that the stray light has been eliminated by a combi-
laboratory that has participated in intercomparisons of stan-
nation of internal baffling, merging of two determinations in
dards of spectral irradiance, largely through the traceability of
which the wavelength region below 320-nm is measured
the standard lamps and associated power supplies employed to
employing secondary filters to reject all wavelengths longer
calibrate the spectroradiometer according to G138, the manu-
than 320 nm, other techniques, or combinations of these.
facturer‘s specified procedures, or CIE Publication 63.
5.1.3 When an integrating sphere is used, the exit port (to
4.7 The accuracy of calibration measurements performed
the monochromator) and entrance port (that represents the
employing a spectroradiometer is dependent on, among other
receiver) should be oriented 90° to each other and the sphere
requirements, the degree to which the temperature of the
should be equipped with a baffle to occlude all light that might
mechanical components of the monochromator are maintained
reach the exit directly from the entrance port.
during field measurements in relation to those that prevailed
5.1.4 When a pyrheliometer-comparison tube, or other
during calibration of the spectroradiometer. [1]
view-limiting device, is used for the purpose of calibrating, for
example, ultraviolet pyrheliometers, the pyrheliometer-
5. Apparatus
comparison tube should ideally be affixed to the entrance port
5.1 Reference Spectroradiometers:
of the integrating sphere such that the sphere’s entrance port
5.1.1 The spectroradiometer employed as the reference becomes the aperture stop of the view-limiting device. Under
radiometershall,regardlessofwhetheritconsistsofascanning
most circumstances, the pyrheliometer comparison tube should
or a linear-diode-array monochromator, be calibrated in accor- possess the optical geometry defined by the World Meteroro-
dance with the procedures specified by G138. CIE Publication
logical Organization, the principal one being a 5.6° field of
63, or specific calibration procedures required by the manufac- view.
turer. and the manufacturer.
NOTE 7—When the sphere’s entrance port is the occluder’s aperture
5.1.1.1 It is recommended that the reference
stop,nocalibrationofthespectroradiometerisrequiredindependentofthe
spectroradiometer, or one of its exact type, has been a
calibration with only the integrating sphere in place. If the occluder’s
participating spectroradiometer in an intercomparison of spec-
aperture stop is integral with the occluder and of different smaller
dimension than the sphere’s entrance port, the spectroradiometer must be
troradiometers either managed, sponsored, or sanctioned by a
calibrated with the occluder attached to the integrating sphere . resulting
national metrological laboratory, or another appropriate body.
in greater uncertainties and the possibilities of significant errors.
Such interlaboratory comparisons should include the spectral
5.2 Computational Facilities—The computer-based compu-
range of interest in the application. See references [2-6]
tational facilities used to import the raw data with respect to
5.1.1.2 Alternatively, it is recommended that the reference
wavelength and intensity should be capable of providing
spectroradiometer shall be calibrated by measurement of a
analyzed spectral irradiance information integrated across any
primary spectral irradiance standard reference lamp source
wavelength band chosen.
produced by a national metrological laboratory,(NMI) or mea-
5.3 Instrument Mounts:
5.3.1 Equatorial Mount—An altazimuthal or equatorial,
The Spectrodiometric Measurement of Light Sources, Publication No. 63, The
International Commission on Illumination (CIE). follow-the sun mount that is equipped with a platform on
G130 − 12 (2020)
calibration to the FWHM of the instrument’s spectral response functions
which the spectroradiometer is mounted is required for all
will result in significant instrument-to-instrument differences when mea-
hemispherical normal-incident and direct (beam) calibrations
suring sources having the same spectral energy distributions. In this case,
measurements.
the users or specifications should state the exact wavelength interval that
5.3.2 Tilt Table—A stable, adjustable tilt table having tilt
will be used for all calibrations.
and azimuth adjustments is required for global solar radiation
6.3 Measurement of Light-Source Radiation for Calibration
measurements (for example, at horizontal orientation) and
Using Sunlight:
hemispherical measurements at specified azimuthal and tilt
6.3.1 Mount the radiometer to be calibrated in the geometri-
positions.
cal configuration and aspect that will be employed in its
NOTE 8—An altazimuthal mount so equipped also may be used as the
end-use application.
tilt table.
6.3.2 Affix the spectroradiometer to the mount required for
5.3.3 Optical Platform—A stable, platform equipped with themeasurementsbeingperformed(forexample,anequatorial,
follow-the-sun mount; a tilt table; or, a horizontal bench).
height adjustment is required for use in measuring the calibrat-
ing radiometers against light sources such as arrays, solar 6.3.3 Ensure that both the radiometer being calibrated and
simulators, special lamps, and burners, etc. the spectroradiometer are positioned at the same azimuth angle
with respect to the sun, and at the same tilt from the horizontal.
NOTE 9—When using a fiber-optic/integrating sphere source configu-
6.3.4 Perform these calibration measurements only under
ration to calibrate radiometers, for example, against Xenon-arc lamps,
clear sky conditions by ensuring that no cloud is within less
carbon arcs, and other burners employed in indoor exposure cabinets,
special fixtures may be required to rigidly mount and present the source
than 30° of the sun during any one measurement sequence.
optics to the source of irradiance. For UV-A
...