I NlST Measurement Services: 

Radiance Temperature Calibrations 

NlST 

Special 

Publication 

25043 

Charles E. Gibson, Benjamin K. Tsai, and Albert C. Parr 

U.S. Department of Commerce 

Technology Administration 

National Institute of Standards and Technology 
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2Some elements at Boulder, CO. 
NlST Special Publication 250-43 

NlST MEASUREMENT SERVICES: 

Radiance Temperature Calibrations 

Charles E. Gibson, Benjamin K. Tsai, and Albert C. Parr 

Optical Technology Division 

Physics Laboratory 

National Institute of Standards and Technology 

Gaithersburg, MD 20899-0001 

January 1998 

U.S. DEPARTMENT OF COMMERCE 

William M. Daley, Secretary 

Technology Administration 

Gary R. Bachula, Acting Under Secretary for Technology 

National Institute of Standards and Technology Raymond G. Kammer, Director 
National Institute of Standards and Technology Special Publication 25043 

Natl. Inst. Stand. Technol. Spec. Publ. 250-43, 123 pages (Jan. 1998) 

CODEN: NSPUE2 

U.S. GOVERNMENT PRINTING OFFICE 

WASHINGTON: 1998 

For sale by the Superintendent of Documents, US. Government Printing Office, Washington, DC 20402-9325 
PREFACE 

The calibration and related measurement services of the National Institute of Standards and 

Technology are intended to assist the makers and users of precision measuring instruments in 

achieving the highest possible levels of accuracy, quality, and productivity. NIST offers over 300 

different calibrations, special tests, and measurement assurance services. These services allow 

customers to directly link their measurement systems to measurement systems and standards 

maintained by NIST. These services are offered to the public and private organizations alike. 

They are described in NIST Special Publication (SP) 250, NIST Calibration Services Users 

Guide. 

The Users Guide is supplemented by a number of Special Publications (designated as the “SP250 

Series”) that provide detailed descriptions of the important features of specific NIST calibration 

services. These documents provide a description of the: (1) specifications for the services; (2) 

design philosophy and theory; (3) NIST measurement system; (4) NIST operational procedures; 

(5) assessment of the measurement uncertainty including random and systematic errors and an 

error budget; and (6) internal quality control procedures used by NIST. These documents will 

present more detail than can be given in NIST calibration reports, or than is generally allowed in 

articles in scientific journals. In the past, NIST has published such information in a variety of 

ways. This series will make this type of information more readily available to the user. 

This document, SP250-43 (1997), NIST Measurement Services: Radiance Temperature 

Calibrations, is a revision of SP250-7 (1987). It covers the calibration of radiance temperature 

standards for disappearing filament optical pyrometers, ribbon filament lamps, and radiation 

thermometers (test numbers 350 1OC-35070s in SP250, NIST Calibration Services Users Guide). 

Inquiries concerning the technical content of this document or the specifications for these 

services should be directed to the author or to one of the technical contacts cited in SP250. 

NIST welcomes suggestions on how publications such as this might be made more useful. 

Suggestions are also welcome concerning the need for new calibrations services, special tests, 

and measurement assurance programs. 

Stanley D. Rasberry 

Director 

Measurement Services 

Katharine B. Gebbie 

Director 

Physics Laboratory 

iii 
ABSTRACT 

This document describes the realization and dissemination of the International Temperature Scale 

of 1990 (US-90) above 700 "C at the National Institute of Standards and Technology (NIST). By 

using fundamental principles of blackbody physics, the US-90 scale is first fixed at the freezing 

point of gold (T90 = 1064.18 "C) and is then extended to temperatures between 700 "C and 

2700 "C by determining the ratio of the spectral radiance of a tungsten ribbon filament lamp to 

that of a gold fixed-point blackbody at a wavelength of 655.3 nm. A description of the facilities 

in the NIST Radiance Temperature Calibration Laboratory is given, along with a discussion of 

the wavelength calibration, size of source, and linearity issues. The use and calibration of 

radiance temperature standards are explained. Values of stability and uncertainties in the scale 

are reported. The expanded uncertainties (k = 2) at 800 "C and 2300 "C are 0.6 "C and 1.4 "C for 

ribbon filament lamps, 4 "C and 7 "C for disappearing filament optical pyrometers, and 2 "C and 

3 "C for infrared radiation thermometers. 

KEYWORDS: gold-point blackbody, International Temperature Scale (lTS-90), 

pyrometers, pyrometry, radiance temperature calibration, radiation 

thermometry, tungsten ribbon filament lamps 

iv 
TABLE OF CONTENTS 

Abstract ........................................................................................................................................ iv 

1 . Introduction .............................................................................................................................. 1 

2 . Measurement theory ................................................................................................................. 4 

3 . Realization of the US . national scale of radiance temperature ................................................ 9 

3.1 1990 NET scale of radiance temperature ....................................................................... 9 

3.2 Temperature standards .................................................................................................... 9 

3.2.1 Gold-point blackbody ............................................................................................ 9 

3.2.2 Tungsten ribbon filament lamps .......................................................................... 11 

3.2.3 Working standard lamps ...................................................................................... 14 

3.2.4 Variable-temperature blackbody .......................................................................... 15 

3.3 NIST photoelectric pyrometer ...................................................................................... 19 

3.3.1 Measurement system ........................................................................................... 19 

3.3.2 Optical system ..................................................................................................... 21 

3.3.3 Interference filters ................................................................................................ 22 

3.3.4 Detectors .............................................................................................................. 23 

3.3.5 Linearity of response ........................................................................................... 24 

3.3.6 Wavelength calibration ........................................................................................ 27 

3.3.7 Size of source effect ............................................................................................. 29 

..................................................................... 30 

3.5 Quality control .............................................................................................................. 32 

3.4 Radiance temperature scale uncertainties 

4 . Tungsten ribbon filament lamp calibrations ........................................................................... 37 

4.1 Lamp preparation .......................................................................................................... 37 

4.2 Lamp calibration ........................................................................................................... 37 

4.4 Lamp calibration uncertainty 

4.3 Lamp data analysis ........................................................................................................ 38 

........................................................................................ 40 

5 . Disappearing filament optical pyrometer calibrations ........................................................... 44 

...................................................................................... 44 

....................................................................................... 44 

.................................................................... 45 

5.1 Optical pyrometer preparation 

5.2 Optical pyrometer calibration 

5.3 Optical pyrometer data analysis .................................................................................... 44 

5.4 Optical pyrometer calibration uncertainty 
TABLE OF CONTENTS (continued) 

6 . Radiation thermometer calibrations ....................................................................................... 49 

6.1 Radiation thermometer preparation .............................................................................. 49 

6.2 Radiation thermometer calibration ............................................................................... 49 

6.3 Radiation thermometer data analysis ............................................................................ 49 

6.4 Radiation thermometer calibration uncertainty ............................................................. 49 

7 . Modifications to the NIST photoelectric pyrometer .............................................................. 53 

Acknowledgments ....................................................................................................................... 54 

References ................................................................................................................................... 55 

Appendix A: Ribbon filament lamp sample calibration report ................................................. A1 

Appendix B: Optical pyrometer sample calibration report ........................................................ B1 

Appendix C: Radiation thermometer sample calibration report ................................................ C1 

Appendix D: Radiance temperature measurement services laboratory procedure manual ......... D1 

Appendix E: How to request radiance temperature calibration services .................................... E1 

vi 
LIST OF FIGURES 

Figure 1 Schematic of optics for the NIST photoelectric pyrometer ........................................... 4 

Figure 2 Blackbody spectral distribution . As the temperature increases. the peak moves 

toward shorter wavelengths. and the slope increases at each wavelength ..................... 5 

Figure 3 Schematic of gold-point blackbody ............................................................................. 10 

Figure 4 Gold-point blackbody liquid-to-solid phase transition ................................................ 11 

Figure 5 Gold-point blackbody control system ......................................................................... 12 

Figure 7 Typical lamp currents for the General Electric 30A/T24/6 ribbon filament lamp ...... 14 

Figure 8 Ribbon filament lamp .................................................................................................. 16 

Figure 9 Calibration history of the working standard (no . SL20) ............................................ 17 

Figure 11 Variable temperature blackbody control system ......................................................... 18 

Figure 12 Spatial scan of the variable temperature blackbody at 2000 "C . The temperature 

differences are from the center position (0.0) ............................................................. 18 

Figure 13 Variable temperature blackbody PID control . After decreasing the set point by 

100 "Cy the blackbody stabilizes in less than 10 min .................................................. 19 

Figure 14 NIST photoelectric pyrometer ..................................................................................... 20 

Figure 15 NIST radiance temperature laboratory measurement system ...................................... 21 

Figure 16 NIST photoelectric pyrometer filter transmittances . The wavelength of the 

pyrometer is selected by using a 1 nm and a 10 nm spectral bandwidth (SBW) 

filter ............................................................................................................................. 22 

Figure 18 Relative spectral response of the NIST photoelectric pyrometer ................................ 28 

Figure 19 The size of source corrections for the variable temperature blackbody to the 

Figure 6 Schematic of lamp current monitoring system ............................................................ 13 

Figure 10 Schematic of the variable temperature blackbody ....................................................... 17 

Figure 17 The linearity correction factors for the PEP ................................................................ 25 

working standard lamp comparison and the working standard lamp to the 

gold-point blackbody ................................................................................................... 30 

Figure 20 Calibration history of the ribbon filament lamp check standards ................................ 35 

Figure 2 1 Calibration history of the radiation thermometer check standard 

(Minolta Cyclops 52) ................................................................................................... 36 

Figure 22 Calculation of Icom from Tmean and AVAT .................................................................... 39 

Figure 23 Graph of Tmean and AZ/AT ............................................................................................ 40 

Figure 24 Modified NIST photoelectric pyrometer ..................................................................... 53 

vi i 
LIST OF TABLES 

Table 1 

Table 2 

Table 3 

Table 4 

Table 5 

Table 6 

Table 7 

Table 8 

Table 9 

Table 10 

Table 11 

Table 12 

Table 13 

Table 14 

Radiance temperature calibration services .................................................................. 2 

Calibration uncertainties ............................................................................................. 3 

Current amplifier normalization factors .................................................................... 24 

Detector system correction factors and linearity coefficients .................................... 25 

Default hardware settings used by calibration program .............................................. 26 

Corrections ("C) to the radiance temperature at 900 nm and at 1000 nm ................... 29 

Typical values of WS variables and parameters .......................................................... 33 

Uncertainty budget for the NIST WS lamp spectral radiance realization ................... 34 

Typical values of TL variables and p. arameters ........................................................... 42 

Uncertainty budget for the TL spectral radiance calibration ....................................... 43 

Uncertainty budget for the DF spectral radiance calibration ....................................... 48 

Typical values of RT variables and parameters .......................................................... 51 

Uncertainty budget for the RT spectral radiance calibration ....................................... 52 

Typical values of DF variables and parameters ........................................................... 47 

viii 
1. Introduction 

The National Institute of Standards and Technology (NIST) is responsible for the 

establishment, maintenance, and dissemination of the U.S. National Scale of Radiance 

Temperature through its Radiance Temperature Calibration Laboratory (RTCL), which provides 

temperature measurements above 700 "C. The 1990 NIST Radiance Temperature Scale [l] is 

based upon the NIST realization of the International Temperature Scale 1990 [2] using principles 

from blackbody physics. Beginning with the determination of the freezing point of gold 

(T90 = 1064.18 "C), the scale is realized for the range from 700 "C to 4200 "C using radiometric 

methods. The radiance temperature (also referred to as the brightness or apparent temperature) 

of a radiator is equivalent to the temperature of a blackbody with the same radiant intensity as 

that of the radiator's surface at a chosen wavelength. 

This document describes the determination of the ratio of the spectral radiance of a 

tungsten ribbon filament lamp used as a temperature standard to that of a gold fixed-point 

blackbody at a wavelength of 655.3 nm. A description of the NIST RTCL along with the use and 

calibration of radiance temperature standards therein is presented in detail. Issues relating to the 

wavelength calibration, size of source, and linearity of the NIST Photoelectric Pyrometer (PEP) 

are then discussed. Stability and uncertainties in the scale are considered in detail within the 

framework of the NIST policy on uncertainty statements described in reference [3]. 

The NIST disseminates the radiance temperature scale by two methods. The first method 

involves calibrating ribbon filament lamps as radiance temperature standards in the temperature 

range from 800 "C to 2300 "C with expanded uncertainties (k = 2)' of 0.6 "C at 800 "C, and 

1.4 "C at 2300 "C. The second method involves the calibration of customer pyrometers and 

radiation thermometers. Disappearing filament optical pyrometers are calibrated from 800 "C to 

4200 "C with expanded uncertainties (k = 2) of 4 "C at 800 "C, 7 "C at 2300 "C, and 25 "C at 

4200 "C. Radiation thermometers are measured from 800 "C to 2700 "C with expanded 

uncertainties (k = 2) of 2 "C at 800 "C, and 3 "C at 2700 "C. 

The radiance temperature calibration services shown in Table 1 are offered through the 

NIST Calibration Services Program and are listed in the Radiation Thermometry section of the 

Thermodynamics Quantities Chapter of the NIST Calibration Services Users Guide [4]. A 

summary of the calibration uncertainties is given in Table 2. This laboratory's quality system is 

based on the ANSI/NCSL 2540- 1 - 1994 standard and the ISO/IEC Guide 25. 

' Throughout this paper, all uncertainty values are given as an expanded uncertainty with 

coverage factor k = 2, thus a two standard deviation estimate. Uncertainties of fundamental units 

given as a combined standard uncertainty in other documents are restated as an expanded 

uncertainty (k = 2). 

1 
Table 1. Radiance temperature calibration services 

Service ID No. Measurement Description 

Calibration reports are issued giving the radiance temperature of the blackbody at 655.3 nm 

versus the scale reading, output current, or output voltage. 

35010C Radiance Temperature Standard, Disappearing Filament Optical Pyrometer 

(800 "C to 2400 "C, 4 to 12 points, 1 range) 

35020C Radiance Temperature Standard, Disappearing Filament Optical Pyrometer 

(each additional range up to 4200 "C, only available with No. 35010C) 

35030C Additional Interpolated Values 

35040C Radiance Temperature Standard, Disappearing Filament Optical Pyrometer 

(800 "C to 4200 "C, 3 or fewer points, 1 range) 

Calibration reports are issued giving the radiance temperature of the lamp at 655.3 nm versus 

the lamp current. 

35050C Radiance Temperature Standard, Ribbon Filament Lamp (800 "C to 

2300 "C, 6 to 16 points) 

35060C Radiance Temperature Standard, Ribbon Filament Lamp (800 "C to 

2300 "C, 5 or fewer points) 

Test reports are issued giving the radiance temperature of the blackbody at 655.3 nm, 900 nm, 

or 1000 nm versus the indicated reading, output current, or output voltage. 

35070s Special Tests of Radiation Thermometers 

2 
Table 2. Calibration uncertainties 

Standard Expanded 

Uncertainty Temperature Range 

Ribbon filament lamp 800 "C to 1600 "C 0.7 "C 

1.0 "C 

1.5 "C 

1600 "C to 1900 "C 

1900 "C to 2300 "C 

keds & Northrup 800 "C to 1600 "C 4 "C 

Model 8000 series 1600 "C to 2100 "C 5 "C 

7 "C 

Disappearing filament 2400 "C to 2700 "C 8 "C 

optical pyrometer 2700 "C to 3200 "C 17 "C 

25 "C 

1900 "C to 2300 "C 

3200 "C to 4200 "C 

Pyrometer Instrument 800 "C to 1400 "C 3 "C 

Model 95 1400 "C to 1800 "C 4 "C 

5 "C 

Disappearing filament 2400 "C to 2700 "C 8 "C 

1800 "C to 2400 "C 

optical pyrometer 2700 "C to 3200 "C 12 "C 

Infrared radiation 800 "C to 2000 "C 2 "C 

thermometer 2000 "C to 2700 "C 3 "C 

The expanded uncertainty (coverage factor k = 2) is 

equivalent to a two standard deviation estimate. 

3 
2. Measurement theory 

Temperatures above the freezing point of silver (1234.93 K or 961.78 "C) are defined on 

the International Temperature Scale of 1990 (ITS-90) [2] in terms of the ratio of spectral 

radiances of two blackbody sources, one of which is maintained at the temperature of freezing 

silver, gold (1337.33 K or 1064.18 "C), or copper (1357.77 K or 1084.62 "C). The 1990 NIST 

Scale of Radiance Temperature (1990 NIST) is a realization of the ITS-90 using a gold fixedpoint blackbody. In this section, the blackbody temperature will be defined in terms of the 

spectral radiance. Using the signal measurement equation, the measurement equation for the 

calibration of a transfer standard will be derived. 

The signal measurement equation, defined by Nicodemus and Kostkowski in 1978 [5], 

relates the detector signal output, S [VI2, to the source flux input parameters through a detector 

responsivity term, R;I [AeW-'], by the integral relationship, 

LEGEND 

AS Aperture Stop 

CL Collimating Lens 

DL Diverging Lens 

F1 1 nm bandwidth interference filter 

F2 10 nm bandwidth interference filter 

FS Field Stop 

OL Objective Lens 

I 

OL 

FS 

1 CL ! 

I diameter 

AS 

All units in centimeters. 

Figure 1. Schematic of optics for the NIST photoelectric pyrometer. 

1 DL 

As an aid to the reader, the appropriate coherent SI unit in which a quantity should be expressed 

is indicated in brackets when the quantity is first introduced. 

4 
where LA [W.m-3.sr-’] is the spectral radiance, dil [m] is the wavelength band, 8 [rad] is the angle 

between the aperture normal and the line connecting the aperture centers, dw [sr] is the 

differential solid angle originating at the source aperture as defined by the detector aperture, and 

dA [m2] is the differential source aperture area. For the NIST PEP in figure 1, the spectral 

responsivity RA includes the spectral transmittance of the interference filters, the spectral 

transmittance of all other optical elements, and the spectral responsivity of the detector. In terms 

of its specific components, the spectral responsivity is 

where ZA,OL is the spectral transmittance of the objective lens, z;~,,cL is the spectral transmittance of 

the collimating lens, ZA,F~ is the spectral transmittance of the 1 nm bandpass interference filter, 

ZA,m is the spectral transmittance of the 10 nm bandpass interference filter, ‘;1,DL is the spectral 

transmittance of the diverging lens, QEC is the spectral transmittance of the evacuated window 

cell, and Rhp~p is the detector absolute spectral responsivity. 

5.OE+5 

YL 4.5E+5 

3 4.OE+5 

n 

u) 

E 

: 3.5E+5 - 3.OE+5 

Q) 

0 

c 2.5E+5 

0 

e 2.OE+5 

- 1.5E+5 

8 1.OE+5 

P 

v) 5.OE+4 

O.OE+O 

E 

- E 

lOOOn 

900nm 3 

............... 

............... 

Temp. (“C) ............. 

200 600 1000 1400 1800 2200 

Wavelength (nm) 

Figure 2. Blackbody spectral distribution. As the temperature increases, the peak moves towards shorter 

wavelengths, and the slope increases at each wavelength. 

5 
Spectral radiance LA is the radiant power contained in a defined area, solid angle, 

direction, and wavelength interval, 

where CP is the radiant flux [W], A is the source area, a is the plane angle between the surface 

normal and the direction of propagation [rad], p is the solid angle about that direction [sr], and A 

is the wavelength [m]. A few blackbody distributions from 250 nm to 2500 nm between 800 "C 

and 2300 "C are illustrated in figure 2. For an ideal blackbody in a vacuum environment, 

the relation between spectral radiance, wavelength, and temperature is given by the Planck 

equation [6], 

CIL La = 2 e (exp(c2 /(a T)) - 1) ' (4) 

where CIL is the first radiation constant in radiance form with a value of 119.1044 W.nm2, c2 is 

the second radiation constant with a value of 1.4388 x lo-' nm.K [7], A is the wavelength in 

vacuum, and Tis the temperature [K]. The Planck equation in the form of eq (4) is the definition 

for an ideal blackbody radiator. When using a non-ideal blackbody such as a fixed-point 

blackbody to realize the temperature scale, the following form of the Planck equation is used, 

and temperature is defined as a function of spectral radiance using the following equation 

where Ea is the spectral emissivity of the blackbody (which is equal to unity in the case of an 

ideal blackbody), A is the wavelength in air, and nn is the refractive index of air at 15 "C and 

101,325 Pa. From the Cauchy [8] formula, 

nn = 1 + (2726.43 + 12.288 nm2/(A2 x los6)+ 0.3555 nm4/(A4 x lO-I2))x lo-' , (7) 

the refractive index of air at 655.3 nm is about 1.00028. The temperatures described in this 

document are radiance temperatures. The radiance temperature of a radiator is equivalent to the 

temperature of a blackbody with the same radiant intensity of the radiator's surface at a specified 

wavelength. The relationship between the radiance temperature and the true or thermodynamic 

temperature of a blackbody is given by: 

6 
where T is the thermodynamic temperature, TA is the radiance temperature, A is the mean 

effective wavelength of the NIST PEP (655.3 nm), and EL is the estimated emissivity of the 

blackbody (0.99). 

Determination of the spectral radiance temperature of a working standard (WS) lamp 

requires measurement of the ratio rl, 

(9) sws r, =-, 

Au 

of the signals from the transfer standard and the goldpoint blackbody (Au) with the NIST PEP. 

From eq (2), this measured ratio is actually 

To simplify the complex expression in eq (lo), it is assumed that the spectral radiances Lkws and 

L~A~, spectral responsivities Rkws and R~A~, and amplifier gains GWS and GA~ are independent of 

both direction and spatial location. Furthermore, these three variables can be defined by unique 

for the transfer source and the gold-point blackbody at equivalent wavelengths (to be defined 

later) over the same small wavelength band dil. The solid angle terms can be replaced with the 

definition of the solid angle, 

where Ad is the detector area [m2], 8d is the angle between the optical axis and the normal to the 

detector surface [rad], and D is the distance between the detector area and the source area [m]. 

Assuming that the areas are independent of direction and that the solid angles are independent of 

area or spatial location, this ratio then becomes 

(R, * LA * A, . COS 8, Ad * COS 8d)ws .- D:, q= (R, * LA . A, * COS 8, Ad COS e,),,, 0;s ’ 

where A, is the source area [m2], 8, is the angle between the optical axis and the normal to the 

source surface [rad], R1,ws is the detector responsivity when viewing the transfer source, and 

RLA, is the detector responsivity when viewing the gold-point blackbody. The spectral 

responsivities RAWS and RLA~ are assumed to be equal. If the source aperture areas dA~s and 

7 
&A,, source solid angles dws and dOAu, and the source inclination angles 6~s and eA, are the 

same for measuring both the transfer standard and the gold-point blackbody, the measured ratio 

simplifies to the expression, 

This relationship is the defining equation for the ITS-90 above 1337.33 K. In terms of eq (4), it 

can be written at a discrete wavelength, A, as 

where Ln(Tws) and L~(TA,) are the spectral radiances of the two blackbodies at temperatures T 

and TA,, TAU is the temperature of freezing gold defined as 1337.33 K, and rl is their ratio. In 

principle, a measurement of the ratio at a discrete wavelength with a linear response instrument 

yields the value of T. 

The radiance temperature scale is typically maintained and disseminated on tungsten 

ribbon filament lamps, which possess a repeatable lamp current versus radiance temperature 

relationship. At the NIST, a pyrometer system is presently being used with a mean effective 

wavelength of 655.3 nm. This method requires that the pyrometer relative spectral response 

extends only over a small spectral range, or is known accurately enough to determine the 

wavelength at which the integrands of eq (10) have the same ratio as the integrals. Equation (13) 

above is an approximation, and, in practice, corrections, which will be presented in the next 

section, are used. 
3. Realization of the U.S. national scale of radiance temperature 

3.1 1990 NIST scale of radiance temperature 

The reference temperature standard, a gold fixed-point blackbody (Au) with a 

temperature (TAU) of 1064.18 "C (1337.33 K), and the Planck radiation law are used to realize 

and disseminate the 1990 NIST Radiance Temperature Scale. Equation (5) is used to calculate 

the spectral radiance L/LA,,(A, TA") of the fixed-point blackbody for A = 655.3 nm in all the 

measurements of this calibration facility. Measurements are performed from 800 "C to 2300°C 

for lamps, from 800 "C to 2700 "C for radiation thermometers, and extrapolated to 4200 "C for 

some disappearing filament optical pyrometers. 

The NIST PEP is the transfer device used to compare the spectral radiances of the sources 

by the direct substitution method. The signals are corrected for size of source, amplifier gain, 

and linearity. With these corrections, the spectral radiance and the radiance temperature can be 

determined from eqs (12) and (13). The NIST PEP is a filtered radiometer that uses two 

interference filters to select the bandpass. The spectral bandwidth is 5 nm with a mean effective 

wavelength of 655.3 nm. A photomultiplier tube with an S-20 spectral response is used in the dc 

mode. The measurement spot size is a 0.6 mm by 0.8 mm rectangle. 

A high stability vacuum lamp operated at a single radiance temperature of approximately 

1255 "C is the working standard (WS). By equating eqs (9) and (13), the spectral radiance ratio is 

After applying correction factors to the signals in eq (15) for amplifier calibration (CA), linearity 

(CL), and size of source (Cs), the spectral radiance of the WS1 lamp can be written as 

T- .r 

References regarding linearity issues are presented in Section 3.3.5. The uncertainty analysis in 

Section 3.6 can then be derived from eq (15) for the NIST radiance temperature scale up to the 

calibration of the spectral radiance of the working standard lamp. 

3.2 Temperature standards 

3.2.1 Gold-point blackbody 

In the RTCL, a gold fixed-point blackbody with a calculated emissivity of 0.9999, 

designed and built by the NIST Optical Technology Division, is the primary standard used to 

realize the 1990 NIST Radiance Temperature Scale. The blackbody in figure 3 consists of a 

graphite cavity, a crucible of gold, and a cylindrical heat-pipe furnace. The cavity, which is 

9 
76 mm in length and 6 mm in diameter and has a 60" conical end shown, is made from Ultra "I?' 

grade graphite (spectrographic purities of 10 ppm or less). Surrounding this cavity is a crucible 

containing 0.99999% pure gold. The cavity, along with graphite rings and silica glass spacers, is 

placed in an alumina tube. The front rings define a solid angle with af/6 field of view, while the 

back rings support the thermocouple. A furnace (see fig. 3), which consists of a sodium heatpipe heated by two semi-cylindrical ceramic heater elements inside of a mullite tube, is enclosed 

in a water-cooled housing (631 mUmin) and is operated in an argon environment (37 mUmin 

with furnace door closed and 235 mUmin with furnace door open). 

The gold-point blackbody liquid-to-solid phase transition is shown in figure 4. The 

duration of a melt or freeze plateau is approximately 40 min, and the time delay between these 

observation periods is about 45 min. Measurements during the freeze cycle show a negative 

slope of 20 mK in 30 min. The blackbody is slowly heated over about 8 h before reaching the 

melting point and is typically ramped up over night so that it is held just below the melting point 

the next morning. After the initial heating at 8 A, the melt cycle is begun by increasing the 

current to 8.5 A until the temperature reaches 1071 "C. The freeze cycle is begun by lowering 

the blackbody current to 7.95 A. Then the blackbody current is raised to 8.5 A at 1050 "C to 

begin the melt cycle again. 

1 

2 

3 

4 

5 

6 

7 

s 

cavity 

c r u c 1 b 1 e heat^ pipe semicylindrical heater element 

water-cooling coil 

graphite rings silica glass spacers shutter opening device 5 a 

II I 0 a 0 0 8 a a 

I' ' I 0 0 0 0 

Figure 3. Schematic of gold-point blackbody. 

10 
G 

15 

10 

5 

0 

-5 

.lo 

t - -1 

c I 

Time (min) 

Figure 4. Gold-point blackbody liquid-to-solid phase transition. 

The gold-point blackbody control system shown in figure 5 consists of a 286-based 

personal computer, which regulates the power supply and reads the thermocouple measurements 

from the digital voltmeter. To monitor the set points, platinum and platinum/lO% rhodium 

(type S) thermocouples are inserted into round double bore alumina tubing and are placed in a 

silica glass sheathing which makes contact with the rear end of the crucible. 

3.2.2 Tungsten ribbon filament lamps 

Because of a reproducible radiance temperature versus lamp current relationship, tungsten 

ribbon filament lamps are used in the radiance temperature scale realization and are issued as 

radiance temperature standards. Vacuum lamps are typically used for temperatures from 800 "C 

to 1700 "C, and argon gas-filled lamps for temperatures from 1300 "C to 2300 "C. Gas is 

introduced into the high temperature lamps to slow down the evaporation rate of the tungsten. 

The evaporated tungsten atoms collide with the gas atoms, lose their energy, and re-condense on 

the filament surface before being swept away by convection [9]. 

11 
c 

0 HPF 

PC PS 

GC 

Lo---,, DVM 

ASA 

cw 

DVM 

GC 

H PF 

PC 

PS 

PT 

LEGEND 

Argon Supply and Alarm 

55 "C Chilled Water/Cold Water Switch 

Digital Voltmeter 

Gold-filled Crucible 

Heat Pipe Furnace 

Personal Computer 

Power Supply 

Pt/Pt-10% Rh Thermocouple (Type S) 

Figure 5. Gold-point blackbody control system. 

The lamps have cylindrical glass envelopes and are operated on direct current with the 

base facing downward. A computer-stabilized power supply regulates the lamp current to within 

* 0.2 mA. A schematic of the lamp current monitoring system is shown in figure 6. The 

filament is connected to the screw base by wires, which conduct the current and thereby 

minimize contact problems associated with the screw bases. To achieve the required precise 

alignment, the lamps are rigidly fastened in source mounts that allow translation along and 

rotation about three mutually perpendicular axes. Located at the intersection of the center of the 

lamp filament at the height of the notch opening, the rectangular calibration area on the surface 

of the lamp filament is 0.6 mm wide by 0.8 mm high. The notch is about midway along one edge 

of the filament. An alignment mark or an etched arrow is placed on the envelope opposite the 

side viewed by the pyrometer to permit reproducible angular positioning. Then the lamp is 

rotated so that the arrowhead is centered at the mouth of the notch. 

Some lamps use a pointer that is connected to the filament support to indicate the 

calibration area. The advantage to this approach is a more uniform filament. However, one 

12 
disadvantage is the requirement of predictable filament expansion and contraction for 

reproducible calibration area indication by the pointer. 

Until 1995, the NIST issued General Electric3 type 30A/6V/T24 ribbon filament lamps 

as radiance temperature standards, However, General Electric stopped manufacturing these 

lamps in 1990. The lamp had a glass cylindrical envelope that was 300 mm long and 75 mm in 

diameter and a filament that was 3 mm wide and 50 mm long. Figure 7 shows typical lamp 

currents as a function of temperature for the General Electric ribbon filament lamps. 

SH : 

b DAC 

GPlB 

PS 

pin 1 

common pin 4 

- 

GPlB 

+ 

I I I 

+ I 

LA + 

LEGEND 

CL Current Sensing Leads 

DAC Two-channel 12-bit D/A Converter 

DVM Digital Voltmeter 

GPlB GPlB IEEE-488 Interface 

LA Lamp 

PC Personal Computer 

PS Power Suppy 

SH 0.1 R Shunt 

Figure 6. Schematic of lamp current monitoring system. 

Certain commercial equipment, instruments, or materials are identified in this paper for the sole 

purpose of adequately describing experimental or test procedures. Such identification does not 

imply recommendation or endorsement by the National Institute of Standards and Technology of 

a particular product, nor does it imply that the materials or equipment identified are necessarily 

the best available for the purpose it serves. 

13 
50 1 c I ................................................... 

45 1 I 0 

40 I ........... n 

4 

?! 

c, 35 c 

5 30 

0 

E25 

0 

J 

20 

r................ .... 

..................... 

.... -0 ............ 

..... 0 ............ 

0 

............ 1 .............'.......................... 

b 

0, 

10 n I 

500 1000 1500 2000 2500 

Temperature ("C) 

Figure 7. Typical lamp currents for the General Electric 30A/T24/6 ribbon filament lamp. 

The NIST is currently issuing U.K. General Electric Company (GEC) lamps, although the 

lamps are no longer available from this source. The GEC lamps (type 20/G and 20N) have glass 

cylindrical envelopes that are 235 mm long with a 64 mm diameter. The 20N is a vacuum lamp 

with a filament 1 mm wide by 50 mm long and requires about 10 A dc at 1500 "C. The 20/G is 

a gas-filled lamp with a 2 mm wide by 30 mm long filament and requires about 20 A dc at 

2300 "C. 

In 1992, Type TRU 1100-2350 lamps were purchased from the Moscow Lamp Factory 

(Russia) for testing as radiance temperature standards. Due to a decline in requests for radiance 

temperature standard lamps, the testing was not done. At 2300 OC, about 25 A dc current is 

required from the gas-filled lamp, which has a cylindrical envelope, a 2.5 mm wide by 20 mm 

long filament, and an alignment pointer. The TRU lamps, which have a 35 mm silica glass 

window that projects about 5 mm from the envelope, were used in addition to the GE lamp in the 

NISTNNIOFFI spectral radiance intercomparison [ 101. 

The NIST has also bought type 24/G lamps with double silica glass windows from 

Polaron Engineering LTD (U. K.) for use as working and check standards. These lamps are 

similar in design and construction to the GEC lamps. 

3.2.3 Working standard lamps 

A vacuum tungsten ribbon filament lamp of the Quinn-Lee type [ 11,121 is used in the 

temperature scale realization as the secondary temperature standard which maintains the 

14 
temperature scale between scale realizations and as the transfer standard for calibration 

measurements. The temperature of the working standard lamp (serial number SL20) is 

determined by spectral comparison with the gold-point blackbody. A drawing of this lamp is 

shown in figure 8. This lamp is operated at a single current (7.7788 A dc) to produce a spectral 

radiance about eight times higher than that of the gold-point blackbody at 655.3 nm (a radiance 

temperature of about 1530 K). This lamp is stable to better than 0.1 "C over 100 h when 

operated under these single-level conditions. A graph of the calibration history of the working 

standard from August 1989 to February 1996 is shown in figure 9. 

3.2.4 Variable-temperature blackbody 

The NIST uses a commercial variable-temperature blackbody (VTBB) for its radiance 

temperature transfer standard (See fig. 10). This VTBB was manufactured by Thermogage Inc. 

in Frostburg, MD and was supplied with the Type 11 dual blackbody assembly (2.54 cm or 1 in 

ID cavity), the 48 kW power supply, a control program, the model 7000-1 (4 range) optical 

pyrometer, and a digital temperature computer control module. Modifications requested by the 

NIST include the addition of the water-cooled semi-cylindrical mirrors, and enlarging the 

extension tube opening to accommodate measurements with the NIST PEP. 

The VTBB is operated between 700 "C and 2700 "C. The ranges, which are selected by 

placing different size apertures on the optical control pyrometer, are the low range (700 "C to 

1300 "C), the medium range (1300 "C to 1800 "C), the high range (1 800 "C to 2500 "C), and the 

extra high range (2500 "C to 2700 "C). The electrodes are water-cooled by using a 13 "C (55 OF) 

chilled water source. Before the blackbody is turned on, argon gas displaces the air in the cavity. 

When the VTBB cavity is operating, the argon exits from both the front and back extension 

tubes. 

The variable-temperature blackbody control system regulates the blackbody temperature 

to within k 0.1 "C (see fig. 11). The NIST measures the uniformity of the center partition of the 

Thermogage heater elements, and uses those with a spatial uniformity of better than ?- 0.2 "C at 

2000 "C over an area of 10 mm diameter (see fig. 12). The blackbody heats up to the operating 

point in less than 30 min and responds quickly to temperature changes (see fig. 13). The day-today stability of the blackbody is better than k 0.3 "C, and the 6-month stability is within k 2 "C. 

The VTBB operates between 800 "C and 2700 "C with an estimated emissivity of 0.99 

from analytical modeling. The temperature distribution within the VTBB cavity is less than 

50 "C. The blackbody cavity is composed of a single piece of graphite, which is specially 

tapered for achieving high temperature uniformity. This graphite tube is cylindrically hollow on 

both ends to form two 2.54 cm diameter cavities with a common partition in the center. One 

cavity is used for temperature control, and the other cavity is the blackbody source. 

15 
A 

1.6 mm 

ik 

PYREX 

7 21 

Figure 8. Ribbon filament lamp. 

16 
0.0 

......................... k ......................... 

I 

-0.1 

-0.2 [ 80- 352 

-0.4 

I 

-0.6 

-0.7 

................. 

................. 

......... 

......... 

-0.8 

-0.9 

960 

............................................... 

1226 

I I I 1 I I 

0 200 400 600 800 1000 1200 1400 

Time (h) 

Figure 9. Calibration history of the WS (no. SL20). 

Cylindrical sections 

with finer details 

1\- 

Argon line - Control Pyrometer Endcap 

Extension 

All dimensions 

-. 

in 

00 

4-- 

6 5 

_____ __- __--- 

centimeters. 

Figure 10. Schematic of variable-temperature blackbody. 

17 
PS 

ASA cw 

LEGEND 

ASA 

cw 

PC 

PS 

PTC 

SD 

TS 

VTBB 

Argon Supply and Alarm 

55 "c Chilled WaterKold Water Switch 

Personal Computer 

Power Suppiy 

PID Temperature Controller 

Silicon Detector 

Thermal Stabilizer 

Variable Temperature Blackbody 

Figure 11. Variable-temperature blackbody control system. 

Temperature 

difference ("C) 

0 0 to 0.2 

0-0.2 to 0 

W -0.4 to -0.2 

W -0.6 to -0.4 

-0.8 to -0.6 

m-1 to -0.8 

-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 

Horizontal distance from center (mm) 

Figure 12. Spatial scan of the variable-temperature blackbody at 2000 "C. The 

temperature differences are from the center position (0,O). 

18 
2.5 

2 

n > 

a 

21.5 

Y 

I 

c, 

? 

c, e1 

- 

c 

0 

0 

0.5 

0 

,- - - - - - - - -,- - - - - - - - -, -,- - - - - - - - - 

0 2 4 6 8 10 12 

Time (min) 

Figure 13. Variable temperature blackbody control. After decreasing the set point by 100 "C, the blackbody 

stabilizes in less than 10 min. 

3.3 NIST photoelectric pyrometer 

3.3.1 Measurement system 

The PEP is a NIST designed transfer radiometer, which uses refractive optics to image 

the source onto the detector. The schematic of the NIST PEP is shown in figure 14. A drawing 

of the measurement system is shown in figure 15. The measurement system is completely 

automated and controlled by a personal computer, while the laboratory environment is monitored 

by temperature and relative humidity sensors. Lamps and blackbodies are positioned onto the 

optical axis of the PEP using a closed-loop motor controller system that allows positioning to 

within 0.01 mm. The components of the pyrometer are discussed in the next three sections 

followed by a discussion of the method used to characterize the system in the last three sections. 

19 
64 

1 

A 

64 

.- 3 

I 

20 
Source Table 

LEGEND 

AMP Amplifler PS Power Supply 

DVM Digital Vdtneter RS Room Humidity Sensor 

EM Environmental Monitor TC Thermceiectdc Coder 

GPBB Gad-point Blackbody n Test Lamp 

GPL Gold-pdnt Lamp TS Temperature Sensor 

PC Personal Computer WEB Variable Temperature Blackbody 

PMT Photomultiplier Tube WSL Working Standard Lamp 

Figure 15. NIST radiance temperature laboratory measurement system. 

3.3.2 Optical system 

The first element is the objective lens (OL) which is a 5.8 cm diameter bi-convex lens 

with a focal length of 32 cm. The source is placed at twice the focal length from the lens and is 

imaged with unit magnification onto the field stop (FS), which is located at the back radius of 

curvature. The dimensions of the rectangular field stop are 0.6 mm wide by 0.8 mm high. The 

field stop defines the size and shape of the calibration target area. The next element is the 

collimating lens (CL), which is a 2.45 cm diameter bi-convex lens with a focal length of 

12.94cm. The field stop is placed at the front focal point of this lens with the result being a 

collimated beam with a diameter of approximately 1.2 cm. Next the aperture stop (AS) reduces 

the beam diameter to 1 cm. The beam continues through two interference filters (F1 & F2) 

through a plano-concave diverging lens that spreads the radiant flux over the photomultiplier 

tube cathode. The beam completely covers the surface of the cathode. 

In all cases, the source overfills the objective lens and the aperture stop that corresponds 

to a system with anf-number of 13. The solid angle (4.67 x loe3 sr) used is a cone having a half 

angle of 0.0772 rad (4.4'), the apex of which is at the center of the field stop. 

To align sources, the field stop is removed, and the alignment prism (AP) is placed in the 

21 
path behind the field stop mount. The operator views the lamp filament or blackbody aperture 

and moves the filament or aperture to the target area viewed by the PEP. 

3.3.3 Interference filters 

The PEP uses two interference filters centered on 655.3 nm to produce a very narrow 

spectral bandwidth filter pack with transmitances in the wings six orders of magnitude lower than 

the peak. The first filter is a three-cavity type, and the second is a four-cavity type. Both are 

5.08 cm diameter filters made from polished optical quality glass and are coated with a metal 

film. The regular spectral transmittances of the filters (see fig. 16) were measured from 400 nm 

to 1000 nm in 0.2 nm steps (with a relative expanded uncertainty of 0.3 % at 655 nm) using the 

NIST Transfer Spectrophotometer for Regular Transmittance described in reference [ 131. The 

expanded uncertainty of the wavelength calibration of the spectrometer used to make these 

measurements was 0.5 nm at 655 nm. The first and second filters have spectral bandwidths of 

1 nm and 10 nm, respectively. The central wavelength of the filters measured in series was 

determined to be 654.9 nm with a bandwidth of 2.4 nm when using transmittance data around the 

peak from 644 nm to 667 nm. For the full spectral range, the measured central wavelength was 

836.6 nm with a bandwidth of 9.4 nm. The central wavelength ;1, was determined from the 

following equation for determining the effective wavelength, 

50 I 

45 

40 

Q) 35 

0 5 30 

t: 'E 25 

u) 

2o 

15 

10 

5 

0 

640 645 650 655 660 665 670 

Wavelength (nm) 

Figure 16. NIST photoelectric pyrometer filter transmittances. The wavelength of the 

pyrometer is selected by using a 1 nm and a 10 nm spectral bandwidth (SBW) filter. 

22 
By approximating the integral with finite sums over equal wavelength bandwidths dil, & is found 

to be 

a, = 

where the value of i indicates the wavelength in nm. The spectral bandwidth A& was determined 

from the following integral relationship, 

.dA 

A& = 

'peak 

When the integral is converted into finite sums, the SBW becomes 

'peak 

3.3.4 Detectors 

The PEP uses an 11-stage photomultiplier tube with a quartz window and an extended 

S-20 spectral response to measure spectral radiances. The detector is housed in a 

thermoelectrically cooled (-25 "C) chamber. The anode current is amplified and converted to a 

0.1 V to 10 V signal by a programmable dc current amplifier and measured using a high accuracy 

digital voltmeter, capable of integration times ranging from 0.2 s to several minutes. 

The signals for the test source and the WS lamp can vary by as much as a factor of 1100. 

Because several amplifier gain settings are required to cover this dynamic range, all signals are 

normalized to the lo8 V/A range. The amplifier normalization factors CA are determined by 

measuring the values of the four amplifier feedback resistors. Electrical currents Z in the range 

from 1 nA to 1OOOnA are supplied to the current amplifier, and the output voltages V are 

measured using a digital voltmeter. The resistances R, determined using Ohm's law, V = I R, 

are R7, R8, Rg, and Rlo, for the (lo', lo8, lo9, and 10") V/A ranges, respectively. The 

23 
normalization factors for each range are shown in table 3. 

Table 3. Current amplifier normalization factors 

Range [V/A] Normalization factor 

3.3.5 Linearity of response 

The degree of linearity of the PEP response is determined with a NIST designed 

automated beam conjoiner [14]. A beam from a constant source is split into two branches, 

whose fluxes are independently attenuated or blocked before recombination and further 

attenuation. The flux contribution from both branches is equal to the sum of the fluxes from 

each branch when measured separately (additivity). The device provides 100 levels of flux 

ranging over a factor of about 500. The levels are presented in random order to avoid systematic 

errors, and are interspersed with 25 zero flux levels. A personal computer controls the 

attenuating filters and records the filter positions and radiometer signals. The data is leastsquares fitted to a polynomial response function to determine a correction factor (CL) by which 

the radiometer output signal must be multiplied to obtain a quantity proportional to radiant flux. 

The correction factor is given by 

C, = flux / signal = (A, + A, S + A, - S2) / S , (21) 

where Ao, A,, and A2 are the coefficients found from the least squares approximation and S is the 

signal as defined in eq (1). The current values for the coefficients are listed in table 4. The 

magnitude of linearity correction factors is graphically shown in figure 17. 

The measured instrument response is linear to within 0.2 % for a range of 

photomultiplier anode currents from 0.1 nA to 500 nA. For currents much less than 0.1 nA, the 

signal is limited by noise. In order to ensure linearity of response, the current is restricted to a 

maximum of 500 nA by selection of the appropriate photomultiplier tube voltage. Typical 

default hardware settings used by the calibration program are listed in table 5. 

24 
Table 4. Detector system correction factors and linearity coefficients 

A0 

[VI A1 A2 

[V-ll 

"Ooo2 for 1'0003 for -8.9698 x lo-' 1 -3.1787 x log 5 nA 10 nA 

0' 

I 

Figure 17. The linearity correction factors for the PEP. 

25 
41 41 

4 

Io\ 

3 m 3 v, 

00 

m 

i 

6 

f 

9 

4 

W 

00 

8 

0 0 

01 I2 3 F1 W 8 09 

+ i 

6 

0 41 

X 

v, 

v) 

m 

2 

0 

41 0 41 

X 

00 I00 

2 

* 

41 

X 

IW 

v, 

5 

m 

v) 

v, 

Iv, 

9 

v, 

v, 

Iv, 

z v, 

3 

vi 

Iv, 

[z 

2 

II m m o\ 

2 

26 
3.3.6 Wavelength calibration 

The mean effective wavelength of the PEP is calculated for temperature from 800 "C to 

3000 "C by measuring its relative spectral response in the NIST Visiblemear Infrared Spectral 

Comparator Facility [ 151. The collimating lens, aperture stop, optics enclosure, and PMT system 

of the PEP were set up in the Spectral Comparator Facility and the relative spectral response was 

measured while maintaining the same system geometry as in the RTCL. The PEP was measured 

from 400 nm to 900 nm in 5 nm steps and from 630 nm to 670 nm in 0.2 nm steps. The relative 

spectral response was calculated from the following equation, 

where RpEp(A)is the relative spectral response of the PEP in [AN] as defined in eq (2), SpEp(jl) is 

the signal from the PEP in [VI, S&) is the signal from the monitor detector simultaneous with 

Sp&), &(A) is the signal from the detector working standard (DWS), Smz(jl) is the signal from 

the monitor detector simultaneous with &(A), Rw(A) is the absolute spectral response of the 

DWS, 6 is the calibrated amplifier gain for the DWS in [VIA], and Gp~p is the calibrated 

amplifier gain for the PEP. The PEP results are relative spectral responses because the 

measurement was performed in the overfill mode that resulted in a slightly different spot size. 

From eq (18), the CW was determined to be 655.0 nm and the SBW was calculated to be 5.0 nm 

from eq (20) for data over the 400 nm to 900 nm range. The CW was 655.3 nm with a SBW of 

4.2 nm for the 630 nm to 670 nm data. Relative to the peak value, the measured relative spectral 

responsivity values decrease to about lo4 at 5 nm from the central wavelength and to about loe6 

at 50 nm as illustrated in figure 18. Spectral radiance as defined in eq (4) is a function of a single 

wavelength, A. However, the PEP has a finite bandwidth, and the PEP measures radiance as 

defined by an integral form of the Wien' equation, 

900 

R, dA , C1 L= j 

400 a5 exp(c2 /(a T)) 

which could be used in the ITS-90 definition of eq (14). In the RTCL, the single wavelength 

&, -T, used in eq (4) is be defined as follows, 

27 
where &,-T2 is the mean effective wavelength, LI is the radiance of the test lamp at temperature 

TI, and & is the radiance of the WS at temperature T2. 

All of the temperature measurements are performed for a mean effective wavelength of 

655.3 nm, and these corrections are calculated for the VTBB with an emissivity of 0.99. The 

spectral radiance LL(A, EA, T) of the blackbody is defined by eq (5) to be a function of the 

wavelength, spectral emissivity, and the temperature, while the temperature T(A, L;L EA) is 

defined by eq (6) to be a function of the wavelength, spectral emissivity, and the spectral 

radiance. The following steps are performed to calculate the corrections at 900nm for 

To = 1073 K. 

-- L 

Jan-93 ...... 

* Calculate Lo = 1.2856 W.~m'~.sr-', where A = 655.3 nm, Ea = 1 , and T = TO * Calculate T1 = 1073.53 K, where A= 655.3 nm, Ea= 0.99, and Lz. = Lo 

j Calculate L1 = 68.3 1 W-~m-~-sr-', where A = 900 nm, EZ. = 0.99, and T = TI 

j Calculate T2 = 1072.80 K, where A = 900 nm, = 1 , and Lz. = L1 

The corrections T2 - TO that are added to the radiance temperature at 655.3 nm to determine the 

radiance temperatures at 900 nm and 1OOOnm are given in table 6. These corrections are 

equivalent to a spectral radiance correction of -0.27 % at 900 nm and -0.34 % at 1000 nm. 

1 oo 

lo-' 

1 0-* 

1 0-3 

10-4 

1 0-5 

1 o-6 

400 450 500 550 600 650 700 750 800 850 900 

Wavelength (nm) 

Figure 18. Relative spectral response of the NIST photoelectric pyrometer. 

28 
Table 6. Corrections ("C) to the radiance temperature at 900 nm and at 1000 nm 

Blackbody temperature ("C) 900 nm 1000 nm 

800 -0.20 -0.27 

1100 -0.32 -0.45 

I500 -0.53 -0.75 

1900 -0.80 -1.13 

2300 -1.12 -1.58 

3000 - 1.82 -2.55 

3.3.7 Size of source effect 

Measurements are performed to determine how much of the measured flux is from 

sources other than the target. This additional flux from outside the target area is scattered into 

the measured beam by the optical system. The measurement is performed to determine the size 

of source effect or the sensitivity of the PEP when viewing a 0.6 mm wide by 0.8 mm high target 

area on sources of various sizes. The magnitude of the size of source correction is determined by 

measuring the spectral radiance of a large uniform diffuse source with various apertures in front 

of the source. The large uniform diffuse source designed at NIST is used to measure the source of 

source effect. A 1 kW frosted quartz-halogen lamp is placed in a 20 cm by 23 cm by 20 cm 

vented housing. A lens focuses the lamp onto an opening in the housing that is covered by a 

diffuser. The apertures are on an aperture slide for quick positioning and reproducibility. The 

aperture sizes measured are a 1.4 mm by 25.4 mm slit, a 3 mm by 25.4 mm slit, a 15 mm 

diameter hole, and 25.4 mm diameter hole which approximate the sizes of the WS filament, the 

TL filament, the Au blackbody opening, and the BB opening. The ratio r-1 is the measurement of 

the ratio of the WS to the AuBB in eq (9). The size of source correction is calculated from the 

ratio of the measurements of the 15 mm diameter hole to the 1.4 mm by 25.4 mm slit. The 

spectral radiance correction was 0.09 %, which corresponds to a correction factor of 1.0009 

k 0.0006 and a temperature correction of 0.10 "C. A negligible difference was observed for the 

comparison of the measurements of the 1.4 mm by 25.4 mm slit and the 3 mm by 25.4 mm slit; 

therefore, the correction factor for ratio r2 is 1. The size of source correction for ratios r3 and 1-4 

is -0.13 940 which corresponds to a correction factor of 0.9987 L- 0.0002. The correction was 

calculated from the ratio of the measurements of the 1.4 mm by 25.4 mm slit to the 25.4 mm 

diameter hole. The magnitude of the temperature correction varies from -0.07 "C at 800 "C to 

-0.52 "C at 2700 "C. The size of source corrections are shown in figure 19. Because of flux 

contributions from outside the target area, the larger area BB results in a higher temperature. A 

negative correction is added to subtract the additional flux. 

29 
0.2 1 

0.1 

3 

.- 0 

c, 

L 

m 

0 

r 

-0.4 w 

z 

-0.5 

..... ... 

1255 OC .............................. I,,,, 1111~1111rI~III 

500 1000 1500 2000 2500 3COO 

'A ............................................... A 

A AA A 

.................. -4- -A- ......................... 

A A A . ............................................... 

A 

A 

................................. A ............. 

A 

.............. A 

............. 

A 

-0.6 I 1 

Temperature ("C) 

Figure 19. The size of source corrections for the variable temperature blackbody to the working 

standard lamp comparison and the working standard lamp to the gold-point blackbody. 

3.4 Radiance temperature scale uncertainties 

assumed to be negligible, the propagation of standard uncertainty u(y) for a variable y, 

From the laws of statistical theory, when the covariances of the independent variables are 

can be defined in terms of the following sum, 

where u(xJ are the standard uncertainties. The uncertainty in the WS lamp spectral radiance, 

30 
can be calculated by the root sum of squares (RSS) of the products of partial derivatives with 

their respective uncertainties. This uncertainty ~~(LWS) can be derived directly from the 

measurement equation in eq (16) by using the propagation of standard uncertainty relationship in 

eq (27). The partial derivatives are those of the spectral radiance with respect to the independent 

variables in eq (16) and are listed in eqs (29) through (33). The eleven variables in the 

summation of eq (28) are the following variables: EA^, CIL, YI, CA,WS, CL,WS, CS,WS, Gws, CA,A~, 

CL,A~, CS,A~, or GA~. Since all of the measurements in the RTCL are based on the WS lamp, the 

uncertainty analysis of each calibration service (tungsten ribbon filament lamps, disappearing 

filament optical pyrometers, infrared thermometers) will be completed in Sections 4, 5, and 6 

using the uncertainty in ~~(LWS). 

The measurement equation for the radiance temperature scale from the gold-point 

blackbody to the WS lamp can be represented by eq (16). The partial derivatives of the WS 

spectral radiance in eq (16) with rc 

an 

C, 

n, . A TAU 

c2 

n, . A . TAU 

pect to the variables, na, A, TA~, and c2, are 

c2 

n, A - TAU ] -2 

- j, 

31 
- Lws 

c2 

C, 

The expression in eq (28), 

represents the partial derivatives of LWS with respect to x, where x is one of the eleven variables 

in eq (28). 

Table 7 details typical values of the variables in eq (16), while table 8 summarizes the 

uncertainties in eq (28). The uncertainty ~(TA") in table 8 is derived from the NIST radiometric 

determination of the freezing point of gold [ 161. The combined uncertainty ~(Lws) in the spectral 

radiance of the WS lamp can then be calculated by calculating the RSS from the following 

expression, 

where u@MM) is the digital multimeter uncertainty, u(LTC) is the lamp current uncertainty, and 

up) is the lamp drift uncertainty. From tables 7 and 8, a typical relative expanded uncertainty 

in the WS spectral radiance is equal to (2.870 W-m".pm ".sr-')l(569.9 W.m-2.pm -'.si'), or 

0.50 %. The final value of the WS spectral radiance will be utilized in Sections 4 through 6 to 

continue the uncertainty analyses for each type of calibration service. 

3.5 Quality control 

The Radiance Temperature Measurements Calibration Service ensures quality 

measurements through quality system implementation, internal quality control procedures, 

periodic audits, and interlaboratory comparisons. The Quality System Manual for the Radiance 

Temperature Measurements Calibration Service is based on the ANSIRVCSL 2540- 1 - 1994 

standard [17] and the ISOAEC Guide 25 [18]. The Quality System Manual is organized into 

three sections that form a pyramidal shape. The top section is the Optical Technology Division 

Quality System Policies, the middle section contains the Division Procedures that uniformly 

apply to all the calibration services, and the bottom section is the Calibration Service Procedures 

for each calibration service. Additional information on the Divisions Quality System can be 

found in reference [ 191. 

32 
Table 7. Typical values of WS lamp variables and parameters 

Variable Symbol Value 

Refractive index 

Wavelength 

Freezing temperature of gold 

Second radiation constant 

Emissivity of Au 

First radiation constant 

Ratio of WS signal to Au signal 

WS amplifier calibration correction 

WS linearity correction 

WS size of source correction 

WS amplifier gain 

Au amplifier calibration correction 

Au linearity correction 

Au size of source correction 

Au amplifier gain 

WS spectral radiance 

1.00028 

655.3 nm 

1337.33 K 

14387.69 ym.K 

0.9999 

1.191 x lo8 W+~m~.m-~ 

7.764 

1 

1 

1.0009 

1 x 108 V*A-' 

1 

1 

1 

1 x 108 V*A-' 

569.9 W-m-2-ym-1.sr-' 

33 
Table 8. Uncertainty budget for the NIST WS lamp spectral radiance realization 

Expanded 

Uncertainty component Symbol Uncertainty (k = 2) 

Type A Type B 

Refractive index 

Wavelength 

Freezing temperature of gold 

Second radiation constant 

Emissivity of Au 

First radiation constant 

Ratio of WS signal to Au signal 

WS amplifier calibration correction 

WS linearity correction 

WS size of source correction 

WS amplifier gain 

Au amplifier calibration correction 

Au linearity correction 

Au size of source correction 

Au amplifier gain 

WS lamp spectral radiance 

Digital voltmeter 

WS current 

WS drift 

0.006 

0.000 1 

0.00 1 

0.0006 

0.000 1 

0.001 

0.0002 

0.00002 

0.2 nm 

0.23 K 

0.24 pm.K 

0.0002 

440 

0 V.A-' 

0.570 W/m2/pm/sr 

NIST WS lamp spectral radiance 

NIST WS lamp temperature 

34 
The calibrations resulting from the processes described in this document are derived in 

principle from a complete realization of the radiance temperature scale, and therefore are not 

dependent upon the maintenance of in-house standards. In practice, the realization often omits 

the GPBB comparison and relies upon the spectral radiance that is maintained on the stable 

working standard lamp. The calibration history of the lamp compared to the GPBB is monitored 

to confirm the stability of the lamp (see fig. 9). The working standard lamp is compared to the 

gold point blackbody at least twice a year. Lamp and radiation thermometer check standards are 

periodically measured to ensure the accuracy of the measurements. The calibration history of the 

ribbon filament lamp check standards (Serial numbers P51 and P74) are shown in figure 20, 

while the calibration history of the radiation thermometer check standard (Minolta Cyclops 52) is 

shown in figure 21. The calibration process is further monitored by using control limits in the 

data acquisition and data reduction programs. A check-list is used to track the status of the test 

unit throughout the calibration process. A calibration summary sheet is created for each 

calibrated item to record customer information, measurements performed, test unit information, 

environmental conditions, filenames, and computer programs used for data acquisition and 

reduction. The calibration report is carefully reviewed by a party who was not involved in 

producing the values. 

Audits are performed annually by the Division's quality control team. This calibration 

service participates in bilateral and multilateral laboratory comparisons of radiance temperature 

with various national laboratories usually involving guest scientists [20,2 13. 

500 700 900 1100 1300 1500 1700 1900 2100 2300 2500 

Temperature ("C) 

Figure 20. Calibration history of the ribbon filament lamp check standards. 

35 
4 

3 

4 

c -1 

-2 

-u 

500 1000 1500 2000 2500 

Temperature ("C) 

Figure 21. Calibration history of the radiation thermometer check standard (Minolta Cyclops 52). 

36 
4. Tungsten Ribbon Filament Lamp Calibrations 

4.1 Lamp preparation 

Tungsten ribbon filament lamps are calibrated by NIST for the temperature range 800 "C 

to 2300 "C in terms of the 1990 NIST Radiance Temperature Scale by spectral comparison to a 

standard temperature lamp calibrated at 655.3 nm. New lamps are inspected for filament 

continuity, envelope and window clarity, and filament flatness and centering. A digital 

multimeter is used to check the filament continuity. The envelope or window is checked for 

defects and striations in the optical path. 'The filament is checked to determine that it is flat, 

parallel to the envelope walls, and within 2 mm of being centered in the envelope or window. 

The lamps are cleaned with water and laboratory glassware detergent. 

Test lamps (TL) are operated base down on direct current with the center contact (longer 

filament support for a bipost base lamp) at the positive potential. The test lamps are tested for air 

leaks by turning the lamp on, then off, and then on again after 15 min. If air has leaked into the 

lamp envelope because of bad or broken seals, then the lamp will fail when it is turned on. 

Lamps that pass the leak test are annealed to improve lamp stability. New gas lamps are 

annealed at a radiance temperature of 2350 "C at 655.3 nm for 2 h on direct current and vacuum 

lamps are annealed at 1450 "C for about 14 h. The gas lamps are aged for an additional 50 h at 

2300 "C. 

The lamp orientation chosen for the calibration of a new lamp minimizes the variation in 

lamp output while maintaining the optical axis of the measuring instrument approximately 

normal to the lamp filament. This orientation is determined with the lamp operating at 

approximately 1700 "C for a gas lamp, or 1200 "C for a vacuum lamp. An arrow is etched onto 

the rear surface of the lamp envelope to allow reproducible alignment of this orientation. The 

alignment is performed with the lamp operating base down, the filament vertical, and the optical 

axis of the PEP passing through the lamp envelope and intersecting the center of the filament at 

the height of the notch. The sides of the target area, area 0.6 mm wide by 0.8 mm high, are 

approximately parallel to the sides of the lamp filament. The center of the target area is located 

at the intersection of two orthogonal lines on the filament surface. One line bisects the filament 

lengthwise, and the other passes through the point centered at the mouth of the notch. The lamp 

is positioned so that the etched arrow on the lamp envelope is to the rear, as viewed from the 

PEP. The center of the target area is viewed along the horizontal optical axis of the PEP. A 

plumb line is used to make the notch side of the filament vertical. The image of the lamp 

filament is focused onto the field stop of the PEP to within k2.5 mm. The lamp is then 

successively rotated about the horizontal and vertical centerlines through the target area until the 

tip of the arrowhead is centered at the mouth of the notch. 

4.2 Lamp calibration 

The values of radiance temperature apply when the lamp has been aligned to a specified 

orientation while operating at a designated radiance temperature and after the lamp has reached 

thermal stability at each specified operating current. The WS and TL are aligned as described in 

Section 4.1 at one temperature. At all other temperatures, the TL is translated vertically and/or 

horizontally so that the target area viewed by the PEP is always centered on the lamp filament at 

the height of the notch. No additional rotational alignments are performed 

37 
The initial lamp current that corresponds to 1700 "C is selected from previous data for the 

lamp type. The TL is turned on and set to approximately 1700 "C and aligned after 30 min. The 

spectral radiance ratio of the TL to the WS, r2, is calculated, the WS signal, SWS~, is measured, 

and the TL signal, Sn, that corresponds to1700 "C is calculated. The lamp current is adjusted 

until the measured signal is equal to Sn. After waiting 10 min, the final alignment of the TL and 

the WS is performed and the TL is spectrally compared to the WS to determine its radiance 

temperature. The spectral radiance ratio of the TL to the WS is measured three times by 

alternately translating the WS and the TL to the PEP. If the percent standard deviation of the 

ratio is less then the control limit, then the next calibration point is measured; otherwise, the 

point is repeated. The control limits are equal to the relative standard uncertainty (k = 1) of the 

ratio and were determined from previous calibration data. The control limits are the expected 

uncertainties for the spectral radiance ratio measurement. Next, the TL is aligned and measured 

at 2300 "C after waiting 20 min. The additional calibration temperatures are aligned and 

measured in decreasing order after waiting 10 min. A typical calibration interval is 100 "C. The 

following temperatures are repeated at the previously determined lamp currents to estimate the 

lamps stability: 1700 "C, 2300 "C, 1900 "C, 1500 "C, 1100 "C, and 800 "C. The following data 

is stored in a computer file: nominal temperature, measured temperature, lamp current, and 

spectral radiance ratio. See the "Ribbon Filament Lamp Calibration Procedure'' in Appendix D 

for a more details on lamp calibrations in the RTLC. 

4.3 Lamp data analysis 

The repeated calibration temperatures are averaged and the standard error of the mean is 

calculated and compared to the absolute control limits. These results are used to determine the 

expanded uncertainties listed in the calibration report. 

Calibration data is reported at the nominal temperatures 800 "C, 900 "C, 1000 "C, ... 2300 "C. One method to determine the nominal temperatures is to measure it directly. Through 

an iterative process, the TL is repeatedly measured and the lamp current is adjusted until the 

nominal temperature is actually measured. However, the RTCL calculates the lamp current that 

corresponds to the nominal temperature from measurements of the measured temperature (Tm) 

near the nominal temperature (Tn). 

For a small AT, where AT = Tn - Tm, the small change in lamp current is approximated by 

the slope of the tangent at T and given by 

Az Z(T + AT) - Z(T) -- AT 

wo - lim - = lim dT AT+O AT AT+O 

This limit simplifies to a working equation of the form 

dz I(T + AT) = I(T) + - 

dT AT, 

(35) 

where I(T) is the measured lamp current Zm at Tm and I(T + AT) is the measured lamp current Icon. 

The derivative dZ/dT can be approximated by AUAT, which can be modeled as 

3% 
The coefficients aj are calculated from a least squares fit of two other parameters, Tme. and 

AZ/AT. The first parameter is defined by 

Tm.k + Tm.k+l T, = 

2 9 

and the slope of the line between the calibration points Pk and Pk+l in figure 22 is given by 

Figure 22 shows the shape of the curve for Tm versus Zm. AI/AT(Tmm) is fit to a fifth degree 

polynomial giving the coefficients ai. Figure 23 shows the shape of the curve with of T, and 

Az.ATused to calculate the coefficients aj. From eq (36), the corrected lamp current is 

Tm 

Figure 22. Calculation of I,,, from T,,, and AUAT. 

39 
determined to be 

dz - I,,, - I, + (T” - Tm) * 

T mean 

Figure 23. Graph of T,,, and AUAT. 

A least squares fit of the entire calibration data sets finds the best curve for the data set but not 

necessarily for each data point. This method ensures that the direction of the correction is right 

and has been verified by comparison to the iterative method. Sample data can be found in the 

“Ribbon Filament Lamp Data Reduction Procedure” in Appendix D. 

4.4 Lamp calibration uncertainty 

of the TL, 

To calibrate test lamps (TL), the ratio (r2) of the spectral radiance of the WS lamp to that 

40 
is first measured. Taking into account the correction factors for the signals, the overall 

measurement equation for the 1990 NIST Scale of Radiance Temperature for calibration of the 

TL temperature is 

In a manner similar to eq (28), the uncertainty in the spectral radiance of the WS can be 

represented by the RSS of products of partial derivatives, 

where xi is one of the variables: ETL, CIL, LWS, r2, CA,WS, CL,WS, Cs,ws, Gws, CA,TL, CL,TL, CS,TL, or 

%. The partial derivatives of TTL with respect to na, A, and c2 are 

(cA . ‘L . * ‘)WS 7. 

41 
The partial derivatives of Tn with respect to x are 

where x is one of the variables labeled xi in eq (43). 

Typical values of the variables in eq (42) are shown in table 9, and the uncertainties of 

eq (43) are displayed in table 10. The total expanded relative uncertainty u(Tm)ITn in the TL 

temperature has contributions from w(Tn) in eq (43), from the uncertainty u(TLC) in the TL 

current, and from the uncertainty u(AL) in alignment. These contributions are shown in table 10 

and are summed by the RSS technique as follows, 

From tables 9 and 10, a typical relative expanded uncertainty in the TL temperature realization is 

1.10 W1973.52 K, or about 0.059 %. For other nominal TL temperatures besides 1700 "C, the 

user is referred to table 2. 

Table 9. Typical values of TL variables and parameters 

Variable Symbol Value 

Refractive index 

Wavelength 

Second radiation constant 

Emissivity of TL 

First radiation constant 

WS spectral radiance 

Ratio of TL signal to WS signal 

WS amplifier calibration correction 

WS linearity correction 

WS size of source correction 

WS amplifier gain 

TL amplifier calibration correction 

TL linearity correction 

TL size of source correction 

TL amplifier gain 

TL temperature 

1.00028 

655.3 nm 

14387.69 pm-K 

1 

1.191 x IO* ~.p,m~.m-~ 

569.9 W-m-2y.m-'.sr'' 

2.55 1 

0.09986 

1 

1 

1 

1 

1 

1 x lo8 V-A-' 

1973.52 K 

1 x io9 VA-' 

42 
Table 10. Uncertainty budget for the TL temperature calibration 

Expanded 

Uncertainty component Symbol Uncertainty (k = 2) 

Type A Type B 

Refractive index 

Wavelength 

Second radiation constant 

Emissivity of TL 

First radiation constant 

WS spectral radiance 

Ratio of TL signal to WS signal 

WS amplifier calibration correction 

WS linearity correction 

WS size of source correction 

WS amplifier gain 

TL amplifier calibration correction 

TL linearity correction 

TL size of source correction 

TL amplifier gain 

TL temperature 

TL current 

Alignment 

TL temperature calibration 

0.00002 

0.2 nm 

0.24 pm.K 

0.0002 

440 W.pm4-mT2 

2.998 W. m-2.pm-'. sr- ' 

0.005 1 

0.00001 

0.001 

0.0002 

0.000 1 

0.001 

0.0002 

0 V-A-' 

0.09 K 

0.30 K 

0 VeA-' 

1.10 K 

1.10 K 

43 
5. Disappearing filament optical pyrometer calibrations 

5.1 Optical pyrometer preparation 

Disappearing filament optical pyrometers (DFP) are calibrated from 800 "C to 4200 "C 

by comparison to the VTBB. When the test unit arrives, the batteries are checked, the objective 

lens and eyepiece are cleaned, and the eyepiece is focused onto the DFP lamp filament. The 

lamp is checked to ensure that it is operating and that matching is possible. If an operating 

manual is not on file, then one is requested from the customer because test pyrometers are 

operated according to the manufacturer's instructions unless other instructions are given. The 

pyrometers and associated electronics are initialized according to manufacturer's specifications. 

5.2 Optical pyrometer calibration 

The DFP is 

measured at an appropriate distance from the front surface of the objective lens holder to the 

blackbody cavity partition and is focussed on the center of the partition. After the VTBB is 

turned on, the pyrometer centering is checked and adjusted as necessary. 

For the 800 "C to 2700 "C temperature range, the PEP is used to spectrally compare the 

VTBB to the WS to determine the radiance temperature of the blackbody at each calibration 

temperature. The VTBB and the WS are compared three times and the mean is used. Once the 

temperature of the blackbody has been determined, the test DFP lamp filament is matched in 

brightness to that of the blackbody, and the DFP lamp current is measured using a standard resistor 

and a digital voltmeter. The matching is performed from bright to disappearance and from dark to 

disappearance twice and the mean of the four readings is used. The indicated temperature is 

recorded for pyrometers with either a temperature scale or a digital panel indicator. The output 

voltage is measured for pyrometers with internal current measuring resistors. The DFP 

measurements are not bracketed by VTBB measurements because the VTBB has been shown to be 

stable to within f 0.1 "C during the time required to complete the measurements. 

For temperatures above 2700 "C, the method used to extrapolate the calibration to 4200 "C 

involves measuring temperatures below 2700 "C on two or more ranges. For a three-range DFP 

with a low range (L) from 1100 "C to 1700 "C, a medium range (M) from 1700 "C to 2800 "C, and 

a high range (H) from 2900 "C to 4200 "C, the following measurements are performed. The DFF 

lamp currents are measured for VTBB temperatures from 1100 "C to 1700 "C on the L range, from 

1600 "C to 2700 "C on the M range, and from 1700 "C to 2700 "C on the H range. 

The DFP is aligned onto the geometric center of the VTBB opening. 

5.3 Optical pyrometer data analysis 

The various data reduction methods used are determined by how the DFP indicates 

temperature. In all cases, the data is sorted by range and averaged and the standard deviation is 

calculated. For DFPs with ranges below 2700 "C, the data is analyzed and the blackbody 

temperature versus the scale or panel reading, output current, or output voltage is reported. The 

pyrometer correction, blackbody temperature minus DFP reading, that is added to the pyrometer 

reading is reported for scale and panel indicator DFPs. 

For the three-range DFP case when temperatures are determined above 2700"C, more 

calculations are required before the data is reported. The current measurement averages are fit to 

44 
the curve Z(T) = a0 + a1.T + a2-T2 + a3.T3 calculating a least squares approximation for each DFP 

range. For the L range the blackbody temperatures are calculated at the nominal temperatures 

1100 "C, 1200 "C, ..., 1700 "C and reported versus the pyrometer lamp currents. For the 

M range, the blackbody temperatures are calculated at the nominal temperatures 1700 OC, 

1800 "C, . . . , 2700 "C and reported versus the pyrometer lamp currents. The 2800 "C calibration 

point is determined in two steps. The first step is to calculate AM, the "A" value [22] for the M 

range, which is defined be the relationship, 

where TApp is the apparent temperature [K], TBB is the blackbody temperature [K], z is the filter 

transmittance, and A is the "A" value [K-'I. From eq (44), it becomes apparent that In z must be 

approximately equal to l/A in order for A to be constant. Typically, the value of A is on the order 

of 173~10-~ IC1. TBB, is determined during the M range measurements. TApp is the temperature on 

the L range that corresponds to the current measured on the M range which is determined through 

iteration of the L range function Z(t). The second step is to use the "A" value to calculate the 

pyrometer lamp current that corresponds to the extrapolated blackbody temperature at 2800 "C. 

Use eq (44) to calculate TApp2 when TBB2 = 3073.15 K and A = AM. Next calculate the pyrometer 

lamp current using the L range function Z(t). 

This procedure is repeated to determine the extrapolated blackbody temperatures for the H 

range. The H range "A-value", AH, is determined where TAPP is the temperature on the L range 

that corresponds to the current measured on the H range and TBB is the blackbody temperature 

during the H range measurements. AH is then used to calculate the apparent temperature TAppz for 

each extrapolated blackbody temperature from 2900 "C to 4200 "C. The pyrometer lamp 

currents are calculated from the L range function Z(t). The extrapolated blackbody temperatures 

for the M and H ranges are reported versus the pyrometer lamp currents. 

5.4 Optical pyrometer calibration uncertainty 

radiance of the WS lamp to that of the variable-temperature blackbody (BB), 

To calibrate disappearing filament optical pyrometers (DR), the ratio (r3) of the spectral 

is first measured to determine the radiance temperature of the BB, T(A,Ln,BB), at each 

disappearing filament optical pyrometer temperature by the equation, 

45 
The uncertainty in the spectral radiance of the BB can be calculated by the RSS of products of 

partial derivatives of eq (46) with their respective uncertainties as follows, 

where Xi is one of the following variables: EBB, CIL, r3, CA,WS, CL,WS, CS,WS, GWS, CA,BB, CL,BB, 

CS,BB, or GBB. The partial derivatives of nA, a, and c2 can be derived from eq (46) as 

The expression, 

46 
represents the partial derivatives of TBB with respect to x, where x is one of the variables, EBB, CIL, 

~3, CA,WS, CL,WS, CS,WS, Gs, CA,BB, CL,BB, CS,BB, or GBB. 

A summary of the DFP variable values in eq (46) in table 11. Uncertainty values from 

eq (47) are given in table 12. Table 12 also shows the standard uncertainties leading up to the 

total standard uncertainty in the DFP temperature, 

The uncertainty in the pyrometer temperature is related to the uncertainty in the variabletemperature blackbody temperature by the following relationship, 

~DFP L ~BB ( ~DFP ) ( ~DFP ) 1 

where u(BU) is the blackbody uniformity uncertainty and u(PR) is the pyrometer reading 

uncertainty. The relative expanded uncertainty in the DFP temperature from tables 11 and 12 is 

7.57 W2579.07 K, or 0.29 %. The uncertainty values for other DFP temperatures are listed in 

table 2. 

Table 11. Typical values of DFP variables and parameters 

Variable Symbol Value 

Refractive index 

Wavelength 

Second radiation constant 

Emissivity of BB 

First radiation constant 

WS spectral radiance 

Ratio of BB signal to WS signal 

WS amplifier calibration correction 

WS linearity correction 

WS size of source correction 

WS amplifier gain 

BB amplifier calibration correction 

BB linearity correction 

BB size of source correction 

BB amplifier gain 

BB temperature 

na 

a 

c2 

EBB 

CIL 

Lws 

r3 

cA,WS 

GWS 

CS,WS 

GWS 

CA,BB 

CL.BB 

CS,BB 

GBB 

TBB 

1.00028 

655.3 nm 

14387.69 pm.K 

0.99 

1.19 1 x lo8 W+~m~.m-~ 

569.9 W.m-2.pm-1.sr-1 

3.445 

0.0998 6 

1 

1 

1 x lo9 V.A-’ 

9.978 

0.9997 

0.9987 

2579.07 K 

I x io7 V-A-‘ 

47 
Table 12. Uncertainty budget for the DFP pyrometer temperature calibration 

Expanded 

Uncertainty factor Symbol Uncertainty (k = 2) 

Type A Type B 

Refractive index 

Wavelength 

Second radiation constant 

Emissivity of BB 

First radiation constant 

WS spectral radiance 

Ratio of BB signal to WS signal 

WS amplifier calibration correction 

WS linearity correction 

WS size of source correction 

WS amplifier gain 

BB amplifier calibration correction 

BB linearity correction 

BB size of source correction 

BB amplifier gain 

Digital voltmeter 

BB temperature 

Blackbody uniformity 

DFP reading 

DFP temperature calibration 

0.00002 

0.2 nm 

0.24 pm-K 

0.0002 

440 W+~m~.m-~ 

2.998 W.m-'.pm-'.si' 

0.00682 

0.00001 

0.00 1 

0.0002 

0 V-A-' 

0.00 1 

0.001 

0.0002 

OK 

0.20 K 

7.20 K 

0 V.A-' 

2.34 K 

7.57 K 

48 
6. Infrared thermometer calibrations 

6.1 Radiation pyrometer preparation 

Radiation thermometers (RT) are measured for the temperature range from 800 "C to 

2700 "C. The RTs are operated according to the manufacturer's operating instructions unless 

special instructions are given. First, the lens, eyepiece, and filters are cleaned; then the 

emissivity control is set to unity. The RT is aligned so that its optical axis, when viewing the 

VTBB, coincides with the geometrical center of the blackbody. 

6.2 Radiation pyrometer calibration 

The VTBB is turned on and set to the highest temperature measured. After waiting 

30min, the PEP is used to determine the radiance temperature of the VTBB by spectrally 

comparing it to the WS lamp at each calibration temperature from 2700 "C to 800 "C in 100 "C 

steps. The measurements are repeated at 2300 "C, 1900 "C, 1500 "C, 1100 "C, and 800 "C to 

determine the stability of the RT. The VTBB is compared to the WS three times, and the average 

of the measurements is used. After the temperature of the VTBB is determined, three RT 

measurements of the VTBB are made, and the output current, output voltage, or indicated 

temperature is recorded. The spectral radiance temperatures of the VTBB used in the calibration 

are determined at wavelengths of 655.3 nm, 900 nm, and lo00 nm. For 100 "C temperature 

changes, the VTBB is measured after waiting 5 min for the VTBB to stabilize. 

6.3 Radiation pyrometer data analysis 

For RTs with output currents or voltages, the nominal temperature, the VTBB 

temperature, and the output current or voltage are reported in the test report. For RTs with 

temperature indicators, the nominal temperature, the VTBB temperature, the temperature 

indicated by the RT, and the RT correction are reported in the test report. The RT correction is 

equal to the VTBB temperature minus the RT indicated temperature. 

6.4 Radiation pyrometer calibration uncertainty 

lamp to that of the variable-temperature blackbody (BB), 

To calibrate radiation thermometers (RT), the ratio (14) of the spectral radiance of the WS 

is first measured to determine the radiance temperature of the BB, T(A,LABB), at each test 

temperature by the equation, 

49 
The uncertainty in the spectral radiance of the BB can be calculated by the RSS of the products 

of the partial derivatives in eqs (57) through (60) with their respective uncertainties, 

where xi is one of the following variables: ERT, CIL, r4, CA,WS, CL,WS, CS,WS, GWS, CA,BB, CL,BB, 

CS,BB, or GB. From eq (59, the partial derivatives of nay A, and c2 are 

r 1 

The expression, 

c2 c2 

n, . R TBB * n, . il TBB 1 r4 * 

represents the partial derivatives of TBB with respect to x, where x is one of the variables, ERT, CIL, 

50 
~4, CA,WS, CL,WS, Cs,ws, Gws, CA,BB, CL,BB, CS,BB, or GBB. 

are displayed in table 14. Finally, the total expanded uncertainty shown in table 14 is 

Table 13 shows the typical values of the variables in eq (55). The uncertainties of eq (56) 

The uncertainty in the RT temperature is related to the uncertainty in the variable-temperature 

blackbody temperature by the following relationship, 

From tables 13 and 14, the relative expanded uncertainty in the TRT is 3.05 W2579.07 K, or 

0.12 %. For other RT temperatures, table 2 can be used to approximate the uncertainties. 

Table 13. Typical values of RT variables and parameters 

Variable Symbol Value 

Refractive index 

Wavelength 

Second radiation constant 

Emissivity of BB 

First radiation constant 

WS spectral radiance 

Ratio of BB signal to WS signal 

WS amplifier calibration correction 

WS linearity correction 

WS size of source correction 

WS amplifier gain 

BB amplifier calibration correction 

BB linearity correction 

BB size of source correction 

BB amplifier gain 

BB temperature 

n,2 

a 

c2 

EBB 

CIL 

LWS 

r4 

cA,WS 

CLWS 

cs,ws 

GWS 

CA,BB 

CL,BB 

G,BB 

GBB 

TBB 

1.00028 

655.3 nm 

14387.69 pm-K 

0.99 

1.191 x lo8 Wq.~m~-m'~ 

569.9 W.m-2-pm-'.sr-' 

3.445 

0.09986 

1 

1 

1 x 109V.A-' 

9.978 

0.9997 

0.9987 

1 x lo7 VSA-' 

2579.07 K 

51 
Table 14. Uncertainty budget for the RT temperature calibration 

Expanded 

Uncertainty component Symbol Uncertainty (k = 2) 

Type A Type B 

Refractive index 

Wavelength 

Second radiation constant 

Emissivity of BB 

First radiation constant 

WS spectral radiance 

Ratio of BB signal to WS signal 

WS amplifier calibration correction 

WS linearity correction 

WS size of source correction 

WS amplifier gain 

BB amplifier calibration correction 

BB linearity correction 

BB size of source correction 

BB amplifier gain 

Digital voltmeter 

BB temperature 

Blackbody uniformity 

RT reading 

RT temperature calibration 

0.00002 

0.2 nm 

0.24 pm.K 

0.0002 

440 ~.pm~.m-~ 

2.998 W.m-2.pm-'.sr-' 

0.00579 

0.00001 

0.001 

0.0002 

0 V.A-' 

0.00 1 

0.001 

0.0002 

0 V*A-' 

OK 

2.29 K 

0.20 K 

2.00 K 

3.05 K 

52 
7. Modifications to the NIST photoelectric pyrometer 

The radiance temperature calibrations described in this document are performed using 

the NIST PEP, which is a single wavelength instrument. The spectral radiance temperatures at 

900 nm and 1000 nm are calculated from measurements made at 655.3 nm. Modifications to the 

PEP are underway to allow direct measurements at 900nm and 1OOOnm. The modified 

pyrometer also uses refractive optics, interference filters, and a photomultiplier tube. The 

modifications will include adding a filtered silicon detector and amplifier system, and a laser to 

simplify source alignments. A schematic of the modified PEP is shown in figure 24. The 

methods described in the report to realize the radiance temperature scale at 655.3 nm will be 

employed to realize the scale in the infrared. 

GPL 

WSL 

TL 

VTBB 

TL 

GPBB 

TL 

OL FS AS 

CL 

rl CPD 

I 

LFW +, 

HeNe I 

CEGEND 

AS ApeftureStop HeNe Helium-Neon Laser 

CL Colllmatlng Lens IF Interference Filters 

CPD Cooled Photomultiplier Detector L Lens 

DL Dlverglng Lens OL Objective Lens 

FS 0.6 mm x 0.8 mm PM Plane Mirror 

FW Fllter Wheel lt Test tamp 

GPBB Gold-point Blockbody WBB Variable Temperature Blockbody 

GPL Gold-point Lamp WSL Working Standard tamp 

Rectangular Field Stop SI Silicon Detector 

Figure 24. Modified NIST photoelectric pyrometer. 

53 
Acknowledgments 

The authors would like to thank Robert D. Saunders for his technical assistance in 

reading the manuscript and his constant encouragement. They also like to thank Frank Lovas, 

Dean Ripple, and Chris Kuyatt for useful suggestions and comments. 

54 
References 

Mielenz, K.D., Saunders, R.D., Parr, A.C., and Hsia, J.J., “The 1990 NIST Scales of 

Thermal Radiometry,” J. Res. NIST, 95,621 (1990). 

Preston-Thomas, H., “The International Temperature Scale of 1990 (lTS-90),” Metrologia, 

27,3-10, 107 (1990). 

Taylor, B.N., and Kuyatt, C.E., “Guidelines for Evaluating and Expressing the Uncertainty 

of NIST Measurement Results,” NIST TN 1297 (2nd ed., 1994). 

Simmons, J.D. Ed., “NIST Calibration Services Users Guide,” NIST SP 250,69 (1991). 

Kostkowski, H.J., and Nicodemus, F.E., “An Introduction to the Measurement Equation, 

Chapter 5 of Self-study Manual on Optical Radiation Measurements: Part I - Concepts,” 

NBS TN 910-2,58 (1978). 

Planck, M., “Distribution of Energy in the Spectrum,” Ann. Phys., 4,3,553 (1901). 

Cohen, E.R. and Taylor, B.N., “The 1986 Adjustment of the Fundamental Physical 

Constants,” Review of Modern Physics, 59,4, 1 121 (1987). 

Lide, D.R., “CRC Handbook of Chemistry and Physics,” CRC Press, 67th ed., E-373 

(1 986- 1987). 

Quinn, T.J., “Temperature,” Academic Press Inc., San Diego, CA, 380 (1990). 

Saunders, R.D., Gibson, C.E., Mielenz, K.D., Sapritsky, V.I., Sudarev, KA., Khlevnoy, 

B.B., Mekhontsev, S.N, and Harchenko, G.D. , “Results of a NISTNNIIOFI Comparison L 

of Spectral-Radiance Measurements,” Metrologia, 32,449 (19931 996). 

[ 111 Quinn, T.J. and Lee, R.D., “Vacuum Tungsten Strip Lamps with Improved Stability as 

Radiance Temperature Standards,” Temperature, Its Measurement and Control in Science 

and Industry, Instrument Society of America, Pittsburgh, 4, 1,395 (1972). 

[12] Lee, R.D., Kostkowski, H.J., Quinn, T.J., Chandler, P.R., Jones, T.N., Tapping, J., and 

Kunz, H., “Intercomparison of the IPTS68 Above 1064°C by Four National Laboratories,” 

Temperature, Its Measurement and Control in Science and Industry, Instrument Society of 

America, Pittsburgh, 4, 1,377 (1972). 

[13] Eckerle, K.L., Hsia, J.J., Mielenz, K.D., and Weidner, V.R., “Regular Spectral 

Transmittance,” NBS SP 250-6 (1987). 

55 
[ 141 Saunders, R.D. and Shumaker,J.B., “Automated Radiometric Linearity Tester,” Appl. Opt., 

23,20, 3504, (1984). 

[15] Larason, T.C., Bruce, S.S., and Cromer, C.L., “The NIST High Accuracy Scale for 

Absolute Spectral Response from 406 nm to 920 nm,” J. Res. NIST, 101,2, 133 (1996). 

[ 161 Mielenz, K.D., Saunders, R.D., and Shumaker, J. B., “Spectroradiometric Determination of 

the Freezing Temperature of Gold,” J. Res. NIST, 95,49 (1 990). 

[ 171 “American National Standard for Calibration - Calibration Laboratories and Measuring and 

Test Equipment - General Requirements,” ANSI/NCSL 2540- 1-1994. 

[18] “IS0 Guide 25 General requirements for the competence of calibration and testing 

laboratories,” 3rd edition (1990). 

[19] Bruce, S.S. and Larason, T.C., “Developing Quality System Documentation Based on 

ANSI/NCSL 2540- 1- 1994 : The Optical Technology Division’s Effort,” NISTIR 5866 

(1996). 

[20] Johnson, B.C., Gibson, C., Machin, G., and Rusby, R.L., “Intercomparison of the ITS-90 

radiance temperature scales of the national physical laboratory and NIST,” J. Res. NIST, 99, 

731 (1994). 

[21] Johnson, B.C., Sakuma, F., Sakate, H., Gibson, C., Machin, G., Ricolfi, T., Battuello, M., 

Fischer, J., and Jung, H. J., “International comparison of radiation temperature scales among 

five national metrological laboratories using a transfer standard radiation thermometer,” 

Metrolgia, 33,241 (1996). 

[22] Kostkowski, H.J., and Lee, R.D. “Theory and Methods of Optical Pyrometry,” NBS 

Monograph 41, (1 962). 

56 
Appendix A: Ribbon filament lamp sample calibration report 

In reply refer to: 8441123456-95 

Radiometric Systems Inc. 

Attn: John Doe 

123 Calibration Court 

Measurement City, MD 00000-0000 

Subject : Ribbon Filament Lamp Report of Calibration 

Order No.: AB 1234 dated January 1, 1995 

Dear Mr. Doe: 

Enclosed are results of the calibration you requested for Test Number 35050C Radiance 

Temperature Standard, Ribbon Filament Lamp. Please refer to the above file number in any 

further communication concerning this calibration. 

Sincerely, 

Albert C. Parr, Chief 

Optical Technology Division 

Physics Laboratory 

Enclosures: 

One Report of Calibration 

ACP/j ah 

NIST Cost Center 8443600 

A1 
REPORT OF CALIBRATION 

35050C Radiance Temperature Standard, 

Ribbon Filament Lamp 

for 

Model # General Electric 30NT24/6, Serial # PO00 

Submitted by: 

John Doe 

Radiometric Systems Inc. 

123 Calibration Court 

Measurement City, MD OOO00-0000 

(See your Purchase Order No. AB1234 dated January 1, 1995) 

1. Description of Calibration Item 

A gas-filled tungsten ribbon filament lamp with a mogul screw base was calibrated by the 

National Institute of Standards and Technology (NIST) as a standard of radiance temperature 

from 1000 "C to 2200 "C. The serial number is located on the rear of the lamp envelope 

opposite the side viewed by the pyrometer. 

2. Description of Calibration 

The lamp was calibrated in the NIST Radiance Temperature Calibration Facility using the 

equipment and procedures described in Ref. [I]. The NIST Photoelectric Pyrometer, which has a 

mean effective wavelength of 655.3 nm, was used to spectrally compare the test lamp to working 

standard SL20 to determine its radiance temperature at each test lamp current. The NIST 

Photoelectric Pyrometer is described in the Ref. [ 11. 

The orientation and operation of the test lamp is described in the enclosed NIST SP250-43 

entitled, "Radiance Temperature Calibrations." The calibration was performed with the lamp 

operating on direct current and with the center contact of the lamp base at positive potential. The 

lamp was aligned base down while operating at a radiance temperature of 1700 "C. 

Laboratory Environment: 

Temperature: 24 "C * 1 "C 

Relative Humidity: 25% * 5% 

Calibration Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 1 of 5 

A2 

, 
REPORT OF CALIBRATION 

35050C Radiance Temperature Standard, Ribbon Filament Lamp 

Radiometric Systems Inc. 

Model #: GE 30A/r24/6 

Serial #: PO00 

3. Results of Calibration 

Table 1 gives the radiance temperature of the test lamp at 655.3 nm versus the test lamp current. 

Table 2 gives the calibration uncertainties in relative to the International System of Units (SI 

Units). The expanded uncertainties U = ku, (T) (coverage factor k = 2) are two standard deviation 

estimates. Details on the estimation of these uncertainties are given in Ref. [ 11. The NIST policy 

on uncertainty statements is described in Ref. [3]. 

4. General Information 

The temperatures described in this report are radiance temperatures. The temperatures are stated 

with respect to the 1990 NIST Radiance Temperature Scale and correspond to temperatures when 

sighting on a Planckian radiator. See Ref. [2] for further details on the 1990 NIST Radiance 

Temperature Scale. 

To maintain the highest accuracy, keep the lamp envelope clean and have the lamp recalibrated 

periodically. Appropriate calibration schedules vary with lamp and application and are best 

determined by the user. 

The following was taken from Barber [4]. The radiance temperature below 1500 "C for gas-filled 

lamps and 900 "C for vacuum lamps will change as the room or ambient temperature changes. 

Barber observed a change in radiance temperature for a gas-filled lamp of between 0.3 "C and 

0.4 "C per 1 "C change in room temperature at 1000 "C and 0.05 "C per 1 "C change in room 

temperature at 1400 "C. Changes of the same magnitude were observed at 700 "C and 900 "C for 

a vacuum lamp. 

The results of this calibration apply only to the lamp referenced in this report. This report shall 

not be reproduced, except in full, without the written approval of the Radiance Temperature 

Measurements Calibration Service. 

Prepared by: Approved by: 

Charles E. Gibson 

Optical Technology Division 

Physics Laboratory 

(301) 975-2329 

Robert D. Saunders 

For the Director, 

National Institute of 

Standards and Technology 

(301) 975-2355 

Calibration Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 2 of 5 

A3 
REPORT OF CALIBRATION 

35050C Radiance Temperature Standard, Ribbon Filament Lamp Model #: GE 30A/T24/6 

Radiometric Systems Inc. Serial#: PO00 

References 

C. E. Gibson, B. K. Tsai, and A. C. Parr, "Radiance Temperature Calibrations," NZST 

Special Publication 250-43 (1 997). 

K. D. Mielenz, R. D. Saunders, A. C. Parr, and J. J. Hsia, "The 1990 NIST Scales of 

Thermal Radiometry," J. Res. Natl. Znst. Stand. Technol., 95,621-629, (1990). 

B. N. Taylor and C. E. Kuyatt, "Guidelines for Evaluating and Expressing the Uncertainty 

of the NIST Measurement Results," NZST Technical Note 1297 (2nd ed., 1994). 

C. R. Barber, "Factors affecting the reproducibility of brightness of tungsten strip lamps for 

pyrometry standardization," J. Sci. Znstr. 23,238 (1946). 

Calibration Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 3 of 5 

A4 
REPORT OF CALIBRATION 

35050C Radiance Temperature Standard, Ribbon Filament Lamp Model #: GE 30A/r24/6 

Radiometric Systems Inc. Serial#: POOO 

TABLE 1 

Radiance Temperature of Lamp POOO at 655.3 nm 

Radiance 

Temperature 

(1990 NIST) 

[“CI 

1000 

1100 

1200 

1300 

1400 

1500 

1600 

1700 

1800 

1900 

2000 

2100 

2200 

Lamp 

Current 

[AI 

12.945 

14.220 

15.698 

17.358 

19.191 

21.155 

23.246 

25.449 

27.757 

30.175 

32.669 

35.254 

37.922 

Calibration Date: January 2, 1995 

NIST Test No.: 8441123456-95 

A5 

Page 4 of 5 
REPORT OF CALIBRATION 

35050C Radiance Temperature Standard, Ribbon Filament Lamp Model #: GE 30A/r24/6 

Radiometric Systems Inc. Serial#: PO00 

0.12 

TABLE 2 

Radiance Temperature Calibration Uncertainties 

0.19 

Source of Uncertainty 

0.32 

1. Calibration of the reference 

radiance temperature lamp 

relative to the 1990 NIST 

Radiance Temperature Scale 

B 0.48 

2. Test lamp temperature 

determination 0.29 lA 0.43 

3. Current measurement IB 

4. Mean effective wavelength 

measurement for the NIST 

Photoelectric Pyrometer 

B 

5. Test lamp alignment IB 

0.09 

6. 1990 NIST Radiance 

Temperature Scale relative to 

the Thermodynamic 

Temperature Scale 

B 

0.28 

~~ ~~ 

Expanded Uncertainties (k = 2) ["C] 

800°C 1100°C 1500°C 1900°C 2300 "C 

I 

0.42 I 0.17 

tOslo I O.O4 

0.67 

0.60 

0.14 

0.54 

0.5 1 __ 

0.85 

I 0.6 I 0.4 Overall uncertainty of test lamp * calibration with respect to SI units 0.7 1 1.0 I 1.5 

Calibration Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 5 of 5 

A6 
Appendix B: Optical pyrometer sample calibration report 

In reply refer to: 844/123456-95 

Radiometric Systems Inc. 

Attn: John Doe 

123 Calibration Court 

Measurement City, MD 00000-0000 

Subject: 

Order No.: 

Optical Pyrometer Report of Calibration 

AB 1234 dated January 1, 1995 

Dear Mr. Doe: 

Enclosed are results of the calibration you requested for Test Number 35040C Radiance 

Temperature Standard, Disappearing Filament Optical Pyrometer. Please refer to the above file 

number in any further communication concerning this calibration. 

Sincerely, 

Albert C. Parr, Chief 

Optical Technology Division 

Physics Laboratory 

Enclosure: 

One Report of Calibration 

ACP/j ah 

NIST Cost Center 8443600 

B1 
REPORT OF CALIBRATION 

35040C Radiance Temperature Standard, 

Disappearing Filament Optical Pyrometer 

for 

Model # keds and Northrup 863 1-F, Serial # 0000000 

Submitted by: 

John Doe 

Radiometric Systems Inc. 

123 Calibration Court 

Measurement City, MD 00000-0000 

(See your Purchase Order No. AB 1234 dated January 1, 1995) 

1. Description of Calibration Item 

An optical pyrometer was tested by the National Institute of Standards and Technology (NIST) as 

a standard of radiance temperature from 1149 "C (2100 OF) to 1482 "C (2700 OF). 

2. Description of Calibration 

The test pyrometer was measured in the NIST Radiance Temperature Calibration Facility using 

the equipment and procedures described in Ref. [ 13. The NIST Photoelectric Pyrometer, which 

has a mean effective wavelength of 655.3 nm, was used to spectrally compare the variabletemperature blackbody to working standard SL20 to determine the radiance temperature of the 

blackbody at each calibration temperature. The portion of the test pyrometer lamp filament 

below the wire marker was matched in brightness to that of the blackbody and the test pyrometer 

scale reading was recorded at each calibration temperature. The NIST Photoelectric Pyrometer is 

described in the Ref. [ 11 

The variable-temperature blackbody has an estimated emissivity of 0.99. The blackbody cavity 

is a single piece of graphite, specially tapered for temperature uniformity. This graphite tube is 

cylindrically hollow on both ends to form two 2.54 cm diameter cavities with a common partition 

in the center. One cavity is used for temperature control and the other as a blackbody source. 

Laboratory Environment: 

Temperature: 23 "C k 1 "C 

Relative Humidity: 46% f 5% 

Calibration Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 1 of 5 

B2 
REPORT OF CALIBRATION 

35040C Radiance Temperature Standard, Optical Pyrometer 

Radiometric Systems Inc. 

Model #: L&N 863 1 -F 

Serial #: 0000000 

The test pyrometer was operated according to the manufacturer's operating instructions. The 

pyrometer was calibrated from 1149 "C (2100 OF) to 1482 "C (2700 OF) on the high range (H). 

The pyrometer was aligned so that its optical axis, when viewing the variable-temperature 

blackbody, coincided with the geometrical center of the blackbody. The pyrometer was 

measured at a distance of 8 1.7 cm from the front surface of the objective lens holder to the 

blackbody cavity partition and was focussed on the center of the partition. 

3. Results of Calibration 

Table 1 gives the radiance temperature at 655.3 nm versus the test pyrometer scale reading. 

Table 2 gives the calibration uncertainties relative to the International System of Units (SI Units). 

The expanded uncertainties U = ku, (7') (coverage factor k = 2) are two standard deviation 

estimates. Details on the estimation of these uncertainties are given in Ref. [ 11. The NIST policy 

on uncertainty statements is described in Ref. [3]. 

4. General Information 

The temperatures described in this report are radiance temperatures. The temperatures are stated 

with respect to the 1990 NIST Radiance Temperature Scale and correspond to temperatures when 

sighting on a Planckian radiator. See Ref. [2] for further details on the 1990 NIST Radiance 

Temperature Scale. 

To maintain the highest accuracy, keep the optical components clean and have the pyrometer 

recalibrated periodically. Appropriate calibration schedules vary with instrument and application 

and are best determined by the user. 

The results of this calibration apply only to the pyrometer referenced in this report. This report 

shall not be reproduced, except in full, without the written approval of the Radiance Temperature 

Measurements Calibration Service. 

Prepared by: Approved by: 

Charles E. Gibson 

Optical Technology Division 

Physics Laboratory 

(301) 975-2329 

Robert D. Saunders 

For the Director, 

National Institute of 

Standards and Technology 

(301) 975-2355 

Calibration Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 2 of 5 

83 
REPORT OF CALIBRATION 

35040C Radiance Temperature Standard, Optical Pyrometer 

Radiometric Systems Inc. 

Model #: L&N 8631-F 

Serial #: 0000000 

References 

[ 11 C. E. Gibson, B. K. Tsai, and A. C. Parr, "Radiance Temperature Calibrations," NZST 

Special Publication 250-43 (1 997). 

[2] K. D. Mielenz, R. D. Saunders, A. C. Parr, and J. J. Hsia, "The 1990 NIST Scales of 

Thermal Radiometry," J. Res. Natl. Inst. Stand. Technol., 95,621-629, (1990). 

[3] B. N. Taylor and C. E. Kuyatt, "Guidelines for Evaluating and Expressing the Uncertainty 

of the NIST Measurement Results," NIST Technical Note 1297 (2nd ed., 1994). 

Calibration Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 3 of 5 

84 
REPORT OF CALIBRATION 

35040C Radiance Temperature Standard, Optical Pyrometer 

Radiometric Systems Inc. 

Nominal 

Temperature 

["CI 

TABLE 1 

Radiance Temperature at 655.3 nm 

Blackbody Pyrometer Pyrometer 

Temperature Scale Reading Correction 

[OF1 Value [OF] [OF1 

Temperature 

(1990 NIST) 

roc] 

Model #: L&N 863 1-F 

Serial #: 0000000 

1148.9 1149.2 

1315.6 1316.5 

1482.2 1482.9 

2100.6 2098 3 

2401.7 240 1 1 

2701.2 2700 1 

I High range (H) 

This equation was used to convert the blackbody temperature T from "C to OF: 

T/"F = (1.8 x T/"C) + 32 

Calibration Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 4 of 5 

85 
REPORT OF CALIBRATION 

35040C Radiance Temperature Standard, Optical Pyrometer 

Radiometric Systems Inc. 

Overall uncertainty of test lamp calibration with 

respect to SI units 

Model #: L&N 863 1-F 

Serial #: 0000000 

1.2 1.2 2.3 

(2.2) (2.2) (4.1) 

TABLE 2 

Radiance Temperature Calibration Uncertainties 

Source of Uncertainty 

1. Calibration of the variable temperature 

blackbody relative to the 1990 NIST 

Radiance Temperature Scale 

2. Mean effective wavelength measurement for 

the NIST Photoelectric Pyrometer 

3. Blackbody uniformity 

4. Test pyrometer temperature determination 

5. 1990 NIST Radiance Temperature Scale 

relative to the Thermodynamic Temperature 

Scale 

Expanded Uncertainties (k = 2) 

roc (OF)] 

1148.9 "C 1315.6 "C 1482.2 "C 

(2100 OF) (2400 OF) (2700 OF) 

Type 

Note: The expanded uncertainties in parentheses are in OF. The following equation was used to 

convert the blackbody temperature T from "C to OF: T/"F = (1.8 x T/"C) + 32 

Calibration Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 5 of 5 

B6 
Appendix C: Radiation thermometer sample calibration report 

In reply refer to: 84411 23456-95 

Radiometric Systems Inc. 

Attn: John Doe 

123 Calibration Court 

Measurement City, MD 00000-0000 

Subject: 

Order No.: 

Radiation Thermometer Report of Test 

AB 1234 dated January 1, 1995 

Dear Mr. Doe: 

Enclosed are results of the test you requested for Test Number 35070s Special Test of Radiation 

Thermometer. Please refer to the above file number in any further communication concerning 

this test. 

Sincerely, 

Albert C. Parr, Chief 

Optical Technology Division 

Physics Laboratory 

Enclosure: 

One Report of Test 

ACPljah 

NIST Cost Center 8443600 

c1 
REPORT OF TEST 

35070s Special Test of Radiation Thermometer 

for 

Model # Minolta-Land Cyclops 52, Serial ## 00000000 

Submitted by: 

John Doe 

Radiometric Systems Inc. 

123 Calibration Court 

Measurement City, MD 00000-0000 

(See your Purchase Order No. AB1234 dated January 1, 1995) 

1. Description of Test Item 

A radiation thermometer was tested by the National Institute of Standards and Technology 

(NIST) as a standard of radiance temperature from 800 "C to 2300 "C. The test unit was 

measured with clear filter (Serial Number 0) and dark filter (Serial Number 0). 

2. Description of Test 

The test thermometer was measured in the NIST Radiance Temperature Calibration Facility 

using the equipment and procedures described in Ref. [ 11. The NIST Photoelectric Pyrometer, 

which has a mean effective wavelength of 655.3 nm, was used to spectrally compare the variabletemperature blackbody to working standard SL20 to determine the radiance temperature of the 

blackbody at each calibration temperature. The test thermometer display panel value was 

recorded at each calibration temperature. The NIST Photoelectric Pyrometer is described in the 

Ref. [l] 

The variable-temperature blackbody has an estimated emissivity of 0.99. The blackbody cavity 

is a single piece of graphite, specially tapered for temperature uniformity. This graphite tube is 

cylindrically hollow on both ends to form two 2.54 cm diameter cavities with a common partition 

in the center. One cavity is used for temperature control and the other as a blackbody source. 

Laboratory Environment: 

Temperature: 23 "C f 1 "C 

Relative Humidity: 46% f 5% 

Test Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 1 of 5 

c2 
REPORT OF TEST 

35070s Special Test of Radiation Thermometer 

Radiometric Systems Inc. 

Model #: Miiiolta-Land Cyclops 52 

Serial #: 00000000 

The thermometer was aligned so that its optical axis, when viewing the variable-temperature 

blackbody, coincided with the geometrical center of the blackbody. The test thermometer was 

operated according to the manufacturer's operating instructions and measured with the following 

conditions. 

Temperatures measured: 800 "C to 1200 "C with the clear filter 

1200 "C to 2300 "C with the dark filter 

Distance: 100 cm from the thermometer alignment mark to the blackbody 

cavity partition 

Operating mode: continuous mode 

Calculated target size: 5.6 mm diameter focused on the center of the blackbody cavity 

partition 

Emissivity setting: 1 

3. Results of Test 

Table 1 gives the radiance temperature at 1 OOO nm versus the test thermometer display panel 

value. 

Table 2 gives the test uncertainties relative to the International System of Units (SI Units). The 

expanded uncertainties U = ku, (7') (coverage factor k = 2) are two standard deviation estimates. 

Details on the estimation of these uncertainties are given in Ref. [ 11. The NIST policy on 

uncertainty statements is described in Ref. [3]. 

4. General Information 

The temperatures described in this report are radiance temperatures. The temperatures are stated 

with respect to the 1990 NIST Radiance Temperature Scale and correspond to temperatures when 

sighting on a Planckian radiator. See Ref. [2] for further details on the 1990 NIST Radiance 

Temperature Scale. 

To maintain the highest accuracy, keep the optical components clean and have the thermometer 

recalibrated periodically. Appropriate calibration schedules vary with instrument and application 

and are best determined by the user. 

The results of this test apply only to the thermometer referenced in this report. This report shall 

not be reproduced, except in full, without the written approval of the Radiance Temperature 

Measurements Calibration Service. 

Test Date: January 2, 1995 

NIST Test No.: 8441123456-95 Page 2 of 5 

c3 
REPORT OF TEST 

35070s Special Test of Radiation Thermometer 

Radiometric Systems Inc. 

Prepared by: 

Charles E. Gibson 

Optical Technology Division 

Physics Laboratory 

(301) 975-2329 

Model #: Minolta-Land Cyclops 52 

Serial #: 00000000 

Approved by: 

Robert D. Saunders 

For the Director, 

National Institute of 

Standards and Technology 

(301) 975-2355 

References 

[ 11 C. E. Gibson, B. K. Tsai, and A. C. Parr, "Radiance Temperature Calibrations," NIST 

Special Publication 250-43 (1997). 

[2] K. D. Mielenz, R. D. Saunders, A. C. Parr, and J. J. Hsia, "The 1990 NIST Scales of 

Thermal Radiometry," J. Res. Nutl. Inst. Stand. Technol., 95,621-629, (1990). 

[3] B. N. Taylor and C. E. Kuyatt, "Guidelines for Evaluating and Expressing the Uncertainty 

of the NIST Measurement Results," NIST Technical Note 1297 (2nd ed., 1994). 

Test Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 3 of 5 

c4 
REPORT OF TEST 

35070s Special Test of Radiation Thermometer 

Radiometric Systems Inc. 

TABLE 1 

Radiance Temperature at 1000 nm 

Blackbody 

Temperature 

(1990 NIST) 

["CI 

Nominal 

Temperature 

["CI 

Model #: Minolta-Land Cyclops 52 

Serial #: 00000000 

Thermometer Thermometer Display Panel 

Value 

["CI 

Correction 

["CI 

800 798.7 80 1 

900 899.1 900 

1000 1000.2 1000.5 

1100 1100.6 1100.5 

1200 1200.5 1199.5 

I Clear Filter 

-2.3 

-0.9 

-0.3 

0.1 

1 .o 

2000 

2100 

2200 

2300 

1999.9 1992 7.9 

2099.9 209 1.5 8.4 

2200.7 2191 9.7 

2301.2 2290 11.2 

Test Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 4 of 5 

c5 
REPORT OF TEST 

35070s Special Test of Radiation Thermometer 

Radiometric Systems Inc. 

Model #: Minolta-Land Cyclops 52 

Serial #: 00000000 

B 

TABLE 2 

Radiance Temperature Test Uncertainties 

0.1 

Source of Uncertainty I 800°C 1100 "C 1500 "C 1900°C 2300°C 

lq-T 1. Calibration of the variable 

temperature blackbody 

relative to the 1990 NIST 

Radiance Temperature Scale 

B 0.3 0.3 0.4 

2. Mean 

measurement 

effective 

for 

wavelength 

the NIST 

+ 

Photoelectric Pyrometer 

B 0.1 0.0 0.1 

I Oe3 I OS 

3. Blackbody temperature 

correction 0.2 0.4 0.6 I 0.8 

4. Blackbody uniformity I B I 0.2 0.2 0.2 

5. Test thermometer temperature 

determination A I 2.0 2.0 2.0 2.0 I 2.0 

6. 1990 NIST Radiance 

Temperature Scale relative to 

the Thermodynamic 

Temperature Scale 

B 0. f 0.2 0.4 

I 2.0 I 2.1 I 2.1 I 2.3 I 2.5 Overall uncertainty of test lamp 

calibration with respect to SI units 

Test Date: January 2, 1995 

NIST Test No.: 844/123456-95 Page 5 of 5 

C6 
Appendix D: Radiance temperature measurement services laboratory procedure manual 

i 

D1 
Safety Issues 

Safety glasses are required in lab at all times. 

The following hazards have been identified in this lab. Safety measures are in place to reduce 

risk of injury fiom hazards below. 

BRIGHT SOURCE 

Staring at source is to be avoided because staring can cause severe eye damage. Using correct 

neutral density filter when viewing is required 

BURN 

To avoid burns, it is wise to keep body and clothes away from lamps and blackbodies. 

COLLISION 

The boxcar path should be kept clear of collision with any objects, and cables should not be hung 

from boxcar at any time. 

ELECTROCUTION 

Since high voltage connections are present, electrical parts should not be touched at all. 

LASER 

As with other bright sources, staring into laser is to be avoided because staring can cause severe 

eye damage. When lasers are not in use, block laser with opaque object and turn off laser when it 

is not in use. 

Symbols, similar to one below, are used throughout this document to alert operator to potential 

hazards. 

G:\LPManual\RTMLP Safety. 1 Page 1 

D2 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedures 

Table of Contents 

1. 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

Safety Issues 

Running General Data Taking Program (RTMLP1) 

NIST Photoelectric Pyrometer (PEP) Operation (RTMLP2) 

Gold-point Blackbody (GPBB) Alignment (RTMLP3) 

Gold-point Blackbody Operation (RTMLP4) 

Ribbon Filament Lamp Preparation (RTMLPS) 

Ribbon Filament Lamp Alignment (RTMLP6) 

Ribbon Filament Lamp Operation (RTMLP7) 

Ribbon Filament Lamp Calibration Procedure (RTMLP8) 

Ribbon Filament Lamp Data Reduction (RTMLP9) 

Variable Temperature Blackbody (BB) Alignment (RTMLP 1 0) 

Variable Temperature Blackbody Operation (RTMLP 1 1) 

Disappearing Filament Optical Pyrometer Alignment (RTMLP 12) 

Radiation Thermometer (RT) Alignment (RTMLP 1 3) 

Radiation Thermometer (Optical Pyrometer) Calibration Procedure (RTMLP 14) 

Radiation Thermometer Data Reduction (RTMLP 15) 

G:\LPManual\RTMTOC . 1 

D3 

Page 1 of 1 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Running General Data Taking Program 

Written by: Charles Gibson Procedure: RTMLP 1 

Approved by: Date: 

Revised by: Date: 

Running the General Data Taking Program 

1. Turn on computer 

2. 

3. 

Enter password to work online or click on Cancel button to work offline 

Load Visual Basic program: c: \progrums\dututuknlpyro.muk (do one of following) 

a. 

b. 

Run program (do one of following) 

a. Press F5 

b. Click on b tool bar icon 

C. Click on menu item “Run” then “Start” 

Run Hurdwure.frm to set up equipment with settings used by other programs 

Run Softwure.fim to input data used by other programs 

Run all other programs fiom these forms 

Click on Pyro.mak shortcut icon 

Double click on folder c: \progrums\dututukn\pyro. muk using Windows Explorer 

4. 

5. 

6. 

7. 

G:\LPManual\RTMLP 1.1 

D4 

Page 1 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

NIST Photoelectric Pyrometer (PEP) Operation 

Written by: Charles Gibson Procedure: RTMLP2 

Approved by: Date: 

Revised by: Date: 

NIST Photoelectric Pyrometer (PEP) Operation 

1. Turn on equipment 

a. PMT thermoelectric cooler 

b. Digital multimeters 

C. Motor controller 

d. High voltage power supply 

e. Current amplifier 

f. Environment monitor 

2. Check alignment of optics 

a. 

b. 

c. 

d. 

e. 

f. 

Align laser on source table so that beam goes through center of pin hale aperture 

and field stop 

Check that collimating lens is centered on and normal to optical axis 

(retroreflection checked at field stop) 

Check that aperture stop is centered on and normal to optical axis (place 

microscope slide against aperture stop to check retroreflection at field stop) 

Check scope alignment (see step 3) 

Check that lamp beam is centered on aperture stop 

Record aperture stop micrometer position in lab notebook 

I BRIGHTSOURCE I 

PY COLLISION 

ELECTROCUTION 

G:\LPManual\RTMLP2.1 Page 1 

D5 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP2: Photoelectric Pyrometer (PEP) Operation 

3. Check scope alignment (scope is used to define optical axis of PEP) 

a. 

b. Move lamp to PEP 

C. Close PMT shutter 

d. Open enclosure doors 

e. Open scope door 

f. 

g. Put in field stop 

h. Put inprism 

1. 

j. 

k. 

1. 

m. Remove prism 

n. Remove field stop 

0. Put in prism 

Set up PEP for measurements 

a. 

b. Remove prism 

C. Close scope door 

d. Put in field stop 

e. Close all enclosure doors 

f. 

g. Open PMT shutter 

h. 

Turn on SL20 or other lamp in focal plane of PEP (see RTMLP7) 

Place 3/4" aperture on objective lens 

Focus reticle to operator's eye 

Focus scope on field stop 

Rotate reticle so that #5 vertical scale line is parallel to side of field stop opening 

Position reticle center (intersection of #5 vertical scale line and horizontal scale 

line) on field stop opening 

4. 

Remove aperture from objective lens 

Position baffles at front of PEP 

Begin calibration (see (RTMLPS) for lamps or (RTMLP14) for radiation 

thermometers) 

G:\LPManual\RTMLP2.1 Page 2 

D6 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Gold-point Blackbody (GPBB) Alignment 

Written by: Charles Gibson Procedure: RTMLP3 

Gold-point Blackbody (GPBB) Alignment 

LASER 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

Align laser on source table so that beam goes through center of pin hole aperture and field 

stop 

Move first laser to laser on PEP table 

Align second laser so that it coincides with first laser 

Remove outer most graphite ring 

Put in alignment jig 

Translate GPBB to center jig on laser 

Rotate GPBB to make jig normal to laser (retroreflect laser beam) 

Turn on GPBB (see RTMLP4) 

Radiometrically center GPBB 

a. 

b. 

C. 

d. 

e. 

f. 

g. Check centering 

Center X along horizontal axis 

Center Y along vertical axis 

Center <X about horizontal axis 

Center <Y about vertical axis 

Make '8 turns along optical axis 

Repeat steps a and b until centered 

1. 

11. 

iii. 

Monitor BB signal on graph logger 

Hold card in front of BB opening 

Check for equal signal drop-offs when blocking top, bottom, left, and right 

portions of BB opening 

.. 

G:\LPManual\RTMLP3. I 

D7 

Page 1 
I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Gold-point Blackbody Operation 

Written by: Charles Gibson Procedure: RTMLP4 

Approved by: Date: 

Revised by: Date: 

Gold-point Blackbody (GPBB) Operation 

BRIGHT SOURCE 

I BURN I 

I ELECTROCUTION I 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

Close GPBB door 

Turn on cold water at flow rate of 10 GPH 

Set argon at flow rate of 54 mL/min (set black ball to 50) 

Go to rack of power supplies 

Turn on digital multimeter 

Check that correct cable is connected to GPBB power supply connector 

Switch on power supply (labeled HPPS) 

Run lamp current monitoring program 

a. Turn on computer 

b. Type 2 and press [Enter] at DOS prompt to load and run lamp monitoring 

program 

C. Prepare GPBB 

1. Ramp up GPBB 

(1) 

(2) 

(3) Wait 3 h 

(4) 

(5) 

Press 8 to ramp up GPBB 

Type (start time) and press [Enter] 

program will start ramping up GPBB at start time 

Ramp up GPBB to about 1040 OC 

Set current at 2 A 

Ramp up to 8 A in 4 h (ramping rate 1.5 Ah) 

Set GPBB temperature to about 1040 OC in 8 h to 10 h .. 

11. 

iii. 

iv. 

G:\LPManual\RTMLP4.1 

D8 

Page 1 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP4: Gold-point Blackbody Operation 

d. Cycle GPBB through melt and freeze cycles 

1. 

11. 

iii. 

iv. 

Press 3 to monitor lamps and read GPBB temperature 

Press [Esc] to return to main menu 

Set current to 8.5 A and begin GPBB melt cycle when set point falls below 

1050 "C 

Set current to 7.95 A and begin GPBB freeze cycle when set point rises 

above 1071 "C 

.. 

9. 

10. Open GPBB door 

11. TurnoffGPBB 

Set argon at flow rate of 235 mL/min (set black ball to 120) 

a. Close GPBB door 

b. 

c. 

d. 

Set argon at flow rate of 54 mL/min (set black ball to 50) 

Turn of power to GPBB 

Leave water and argon on overnight until GPBB is cool 

G:\LPManual\RTMLP4.1 

D9 

Page 2 
I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Ribbon Filament Lamp Preparation 

Written by: Charles Gibson Procedure: RTMLP5 

Approved by: Date: 

Revised by: Date: 

Ribbon Filament Lamp Preparation 

BRIGHT SOURCE 

ELECTROCUTION 

1. Lamp inspection 

a. Check filament continuity 

b. 

C. Check flatness of filament 

d. 

Check clarity of envelope (and window) 

Check that filament is within 2 mm of being centered in envelope (or window) 

2. Clean lamp envelope 

3. Anneal lamp 

a. Anneal gas lamp 

1. Leak test lamp 

(1) 

(2) Turnofflamp 

(3) 

(4) 

(5) Wait 15 min 

Anneal lamp for 2 h 

Age lamp for 50 h at 2300 OC (About 42 A dc) 

Set lamp to 1700 OC (PMT signal = 2.5 V on 8 range, high 

voltage = 449 V) (About 25 A dc) 

Wait 15 min to allow air to enter any leaks 

Set lamp to 2350 OC (PMT signal = 1.2 V on 7 range, high 

voltage = 394 V)(About 45 A dc) 

.. 

11. 

iii. 

G:\LPManual\RTMLPS. 1 Page 1 

D10 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLPS: Ribbon Filament Lamp Preparation 

b. Anneal vacuum lamp 

1. Leak test lamp 

(1) 

(2) Turnofflamp 

(3) 

(4) 

(5) Wait 15 min 

Anneal lamp for 14 h 

Set lamp to 1000 "C (PMT signal = 5.3 V on 9 range, high 

voltage = 730 V) 

Wait 15 min to allow air to enter any leaks 

Set lamp to 1450 "C (PMT signal = 5.1 V on 9 range, high 

voltage = 449 V) 

.. 

11. 

Set lamp to 1700 "C for gas lamps or 1200 "C for vacuum lamps (for 1200 "C, 

PMT signal = 5.5 V on 8 range, high voltage = 730 V) 

Use plumb line to make notch side of filament vertical 

Translate lamp horizontally so that reticle center bisects filament lengthwise 

Translate lamp vertically so that reticle center is positioned at center of notch 

opening 

Translate lamp along optical axis until filament is in focus 

Rotate lamp about vertical axis so that both edges of filament are in focus 

Use graph logger to locate angular settings with smallest change in radiance with 

respect to rotation about horizontal and vertical axes 

First person looks through alignment scope and guides second person to notch 

Second person makes dot on lamp envelope at notch 

Draw picture of notch in lab notebook showing its relationship to dot 

Draw arrow showing relationship of alignment arrow to dot 

Repeat steps for each lamp 

4. Locate arrow on lamp 

a. 

b. 

c. 

d. 

e. 

f. 

g. 

h. 

i. 

j. 

k. 

1. 

G:\LPManual\RTMLPS. 1 

D11 

Page 2 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Ribbon Filament Lamp Alignment 

Written by: Charles Gibson Procedure: RTMLP6 

Approved by: Date: 

Revised by: Date: 

Ribbon Filament Lamp Alignment 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

18. 

k BRIGHT SOURCE 

1 COLLISION I 

1 ELECTROCUTION 1 

Check PEP scope alignment (see RTMLP2) 

Place 3/4" aperture on objective lens 

Turn on lamp (see RTMLP7) 

Move lamp to PEP optical axis 

Use plumb line to make notch side of filament vertical 

Translate lamp horizontally so that reticle center bisects filament lengthwise 

Translate lamp vertically so that reticle center is positioned at height of notch opening 

Translate lamp along optical axis until filament is in focus 

Rotate lamp about vertical axis so that both edges of filament are in focus 

Translate lamp horizontally and vertically to reticle center 

Place 1/4" aperture on objective lens 

Place mirror behind lamp alignment arrow 

Rotate lamp about horizontal axis so that tip of arrowhead is positioned at height of notch 

opening 

Rotate lamp about vertical axis so that tip of arrowhead is positioned at notch opening 

Repeat steps 13 and 14 until tip of arrowhead is centered at notch opening 

Translate lamp horizontally and vertically to reticle center at height of notch 

Repeat steps 3 to 16 for standard and test lamps 

Set up PEP for measurements (see RTMLP2) 

G:\LPManual\RTMLP6.1 Page 1 

D12 
I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Ribbon Filament Lamp Operation 

Written by: Charles Gibson Procedure: RTMLP7 

Approved by: Date: 

Revised by: Date: 

kbbon Filament Lamp Operation 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

e 

BRIGHT SOURCE 

ELECTROCUTION 

Use Kimwipe to avoid touching lamp envelope 

Place lamp in socket 

a. 

b. 

Go to rack of power supplies 

Turn on digital multimeter 

Turn on GP-IB Programmer(s) for supply(s) to be used 

a. 

b. 

Check that correct cable is connected to power supply 

Switch on power supply 

Run lamp current monitoring program 

a. Turn on computer 

b. Type 2 and press [Enter] at DOS prompt to load and run lamp monitoring 

program 

C. Set lamp current 

1. 

11. 

iii. 

d. Monitor lamp currents 

1. Press 3 

11. 

Check lamp polarity (center contact for screw base, longer filament support for 

mogal base at positive potential) 

Set alignment arrow or mark away from PEP 

cables and programmers are numbered with corresponding power supply number 

programmers are two channel 12 bit D/A converters 

Press 1 to set power supply current 

Type (supply #) and press [Enter] 

Type (lamp current) and press [Enter] 

.. 

.. Press [Esc] to return to main menu 

G:\LPManual\RTMLP7.1 Page 1 

D13 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP7: Ribbon Filament Lamp Operation 

e. Turn off supply 

1. Press 2 

11. 

f. Change lamp current 

1. same as (1) 

g. Set multiple lamp currents 

1. 

11. 

iii. 

1. 

11. 

1. Check program locking 

.. Type (supply #) and press [Enter] 

Press A to select power supplies to turn on 

Type (lamp current) and press [Enter] to select supplies to turn on 

Type 0 and press [Enter] to skip supply 

Press B to turn off all lamps 

Type OFF and press [Enter] to turn off all lamps 

.. 

h. Turn off all supplies 

.. 

1. Trouble-shoot 

(1) Type Ctrl [Break] 

(2) Type GOT0 20, press [Enter] to return to main menu 

9. Align lamps (see RTMLP6) 

10. Use EMERGENCY TURN OFF procedure when necessary 

a. Go to supply 

b. 

c. Turn off supply 

d. 

Turn CURRENT knob counter clockwise to turn down lamp current 

Turn off GP-IB Programmer for supply 

G:\LPManual\RTMLP7.1 

014 

Page 2 
I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Ribbon Filament Lamp Procedure 

Written by: Charles Gibson Procedure: RTMLP8 

Approved by: Date: 

Revised by: Date: 

Ribbon Filament Lamp Calibration Procedure 

1. Review calibration summary 

a. 

b. 

c. 

Run general data taking program (see RTMLP1) 

Align standard and test lamps (see RTMLPG)) 

a. 

b. 

C. Enter data filename 

d. Enter test filename suffix$ 

1. 

e. Select Yes and use suggested ranges (PMT high voltage and amplifier ranges are 

part of Rtca1.fi.m program) 

f. Click on "Start" button 

g. Enter data on Sofiare.Jim 

Enter lamp and blackbody data 

(1) 

(2) Select "Use" button 

(3) Enter lamp position 

(4) Enter lamp name 

(5) Select "Reference" button 

(6) 

(7) Enter power supply number 

Align and measure test lamp at 1700 "C 

Measure 2300 "C to 800 "C in 100 "C steps 

Repeat 1700 "C, 2300 "C, 1900 "C, 1500 "C, 1100 "C, and 800 "C 

2. 

3. 

4. Run calibration program 

Click on "Calibrations" fiom Hardware.Jim menu to load Rtca1.Ji.m 

Select "Lamps and blackbodies" button 

Create test filenames fiom names on S0fiare.Ji.m 

1. 

Enter data for reference and test lamps 

Enter lamp current (no necessary, lamp current automatically read 

from lamp monitoring computer) 

.. 

11. Select temperature scale 

iii. Select measurement wavelength [nm] 

iv. Enter number of repeats (number of tedstandard measurements) 

G:\LPManual\RTMLP8.1 Page 1 

D15 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLPS: Ribbon Filament Lamp Procedure 

h. 

1. 

j. 

k. 

1. 

m. 

n. 

0. 

P. 

9- 

r. 

S. 

t. 

U. 

V. 

W. 

v. 

vi. Select lamp type 

vii. Select detector channel 

Click on "Save Configuration" button 

Select Tontinuel' button to return to RtcaZ.Jim 

Enter Standard temperature in "C in input box 

Enter Nominal radiance temperature in input box 

Read lamp currents automatically 

Adjust test lamp current so that test lamp signal matches that indicated on 

Suggest.j?m 

Wait for lamp to stabilize (5 min, 10 min, 15 min, or 20 min depending on 

measurement temperature) 

Check lamp alignment 

Move source table to reference source and measure full scale signal 

Move source table to dark signal position and measure dark signal 

Move source table to test source and measure full scale signal 

Move source table to dark signal position and measure dark signal on test source 

amplifier range, if reference and test source amplifier ranges are different 

Repeat steps r to s for each test source 

Repeat steps p to s "number of repeats" times 

Select next action and then select "Continue" button 

1. Repeat measurement with no changes 

11. Measure with new temperature 

iii. Measure with new software changes 

iv. Stop measurements 

Repeat steps k to v for each measurement point 

Enter number of readings (number of readings per DMM trigger) 

.. 

G:\LPManual\RTMLP8.1 Page 2 

D16 
I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLPS: Ribbon Filament Lamp Procedure 

5. Store calibration data in log file "CALMMDD.YY" 

6. Use sample log file below: 1 

1 

Date 08-15-1995 Time 12:49:14 PM 

File Name = CAL0815.95 

PMT Detector 

Wavelength = 655.3 nm 

PMT HV = 449 NRDS = 5 Integration Time = 8.35 s 

Nominal Rad Temp = 1700 "C 

IName SL20 P5 1 

Rad. Temp 1255.07 "C 1700.37 "C 

Current 7.7788 A 26.960 A 

Sp. Rad. 5.696E+02 1.456E+04 

Ratio l.OOOE+OO 2.556E+0 1 

Std. Ratio 0.01% 0.04% 

AmpRange 9 8 

Full Scale 1.052E+00 40.00 ,O 2.685E+00 40. D 

Dark Sig. 

Mean 

Std(Mean) 

Range Cf. 

ss Cf. 

Corr. Mean 

Position # 

Table Pos. 

1.052E+00 *O.OO% 

1.052E+00 40.00% 

1.501E-04 

1.052E+00 

0.01% 

9.9858E-02 

l.OOOE+OO 

1.050E-01 

1 

37500 

2.683E+00 *O.OO% 

2.684E+OO *O.OO% 

2.684E+00 

0.04% 

l.OOOOE+OO 

l.OOOE+OO 

2.684E+00 

6 

246000 

-8.03 5E-05 

G:\LPManual\RTMLPS. 1 

D17 

Page 3 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLPS: Ribbon Filament Lamp Procedure 

7. 

8. 

Store lamp data in test file "XXXXMMDD.YY" 

Use sample test file below: 

P5 108 15.95 

Tnom "C Tmeas "C Imeas "C TesVStandard 

1700 1700.37 26.960 2.555 8E+O 1 

2300 2300.22 43.340 3.4 164E+02 

2200 2200.29 40.330 2.4203 E+02 

2100 2 100.04 37.440 1.6636E+02 

2000 2000.04 34.670 l.l075B+02 

1900 1900.16 3 1.990 7.1 053E+O 1 

1800 1800.13 29.420 4.3 646E+0 1 

08-15-1995 12:49:14 PM 

~~ ~ 

9. Reduce data (see RTMLP9) 

G:\LPManual\RTMLP8.1 

D18 

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Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Ribbon Filament Lamp Data Reduction 

Written by: Charles Gibson Procedure: RTMLP9 

Approved by: Date: 

Revised by: Date: 

Ribbon Filament Lamp Data Reduction 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

Print out test file 

Look in lab notebook and make changes on printout and then edit file 

Load Visual Basic program: c: Iprograms\Zmpredn\Rtred.mak (do one of following) 

a. 

b. 

Run program (do one of following) 

a. Press F5 

b. 

C. 

Select number of lamps to reduce 

Enter 4 character serial number for each lamp 

Enter data file suffix 

Select directory that contains data file 

Select degrees of freedom for curve fit 

Click on "Run" button 

Print data in list box 

Calculate mean (T,,,,) and standard deviation are calculated 

Compare standard deviation to control limit 

Correct lamp current to nominal temperature using following method, because measured 

temperatures are different from nominal temperatures (Tnom) 

a. 

b. 

c. 

d. Calculate dI/dT from fit 

e. 

Store reduced data in log file "REDMMDD.YY" 

Use sample log file on next page: 

Click on Rtred.mak shortcut icon 

Double click on folder c: IprogramsIZmprednlRtred. mak using Windows Explorer 

Click on b tool bar icon 

Click on menu item "Run" then on "Start" 

Fit data to fifth degree polynomial using least squares approximation 

Define independent variable: T,,, = (Tmes(n-l) + Tmeas(n))/2 

Define dependent variable: NIAT = (I,,,,(n-l) - I,,ea,(n))/(T,eas(n-l) - T,,,,(n)) 

Define corrected lamp current: I,,, = I,,,, +dI/dT *(Tnom - T,,,,) 

G:\LPManual\RTMLP9.1 Page 1 

D19 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP9: Ribbon Filament Lamp Data Reduction I I 

Reducing 'C\PYRO\P510815.95' 08-17-1995 11:26:56 AM 

P510815.95 

Tnom "C Tmeas "C ImeasA 

1700 1700.37 26.96 

2300 2300.22 43.34 

2200 2200.29 40.33 

2100 2100.04 37.44 

2000 2000.04 34.67 

1900 1900.16 31.99 

1800 1800.13 29.42 

08-15-1995 12~49~14 PM 

Test/Standard 

2.5 5 5 8E+O 1 

3.4 1 64E+02 

2.4203E+02 

1.6636E+02 

1.1075E+02 

7.1053E+O 1 

4.3 646E+0 1 

Tnom "C Tmean "C Imeas A Std Error Limit Flag Nrpt 

800 800.82 11.850 0.09 0.21 3 

900 899.58 12.720 0.00 0.19 1 

1000 1000.04 13.800 0.00 0.15 1 

1100 1100.02 15.100 0.00 0.09 1 

1200 1199.63 16.620 0.00 0.10 1 

Tnom Imeas Tmeas Tmean DelI/DelT dI/dT DelT Del1 Icon 

"C A "C "C A 

0800 11.850 0800.82 0850.20 0.0088 0.0079 -0.82 -0.007 11.843 

0900 12.720 0899.58 0949.81 0.0108 0.0097 0.42 0.004 12.724 

1000 13.800 1000.04 1050.03 0.0130 0.0119 -0.04 0.000 13.800 

1100 15.100 1100.02 1149.83 0.0153 0.0141 -0.02 0.000 15.100 

1200 16.620 1199.63 1249.74 0.0174 0.0163 0.37 0.006 16.626 

G:\LPManual\RTMLP9.1 Page 2 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP9: Ribbon Filament Lamp Data Reduction 

Zoefficients used to calculate dIldT from a degree polynomial 

7(0)= 0.0635 17488043 157 

7( 1)=-2.4035523727757E-04 

7(2)= 3.5672091 9376003E-07 

73)=-2.29083987235765E-10 

7(4)= 6.90646490071 546E-14 

7(5)=-7.96328820986401 E- 18 

800 11.843 

900 12.724 

1000 13.800 

1100 15.100 

1200 16.626 

1300 18.363 

1400 20.289 

1500 22.376 

1600 24.599 

1700 26.951 

1800 29.417 

1900 31.988 

2000 34.669 

2100 37.441 

2200 40.321 

2300 43.331 

lata is stored in 'C:\PYRO\PS 10895.TXT' 

(eduction of file 'C:\PYRO\P5 108 15.95 ' is complete 

G:\LPManual\RTMLP9.1 Page 3 

D2 1 
Optical Technology 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP9: Ribbon Filament Lamp Data Reduction 

17. 

18. 

19. 

20. 

21. 

22. 

23. 

24. 

25. 

26. 

27. 

28. 

29. 

30. 

Save T,, and I,,, in data file "XXXXMMYY.TXT" 

Use sample test data file below: 

C:\PYRO\P5 10895.TXT 

800 11 343 

900 12.724 

1000 13.800 

1100 15.100 

1200 16.626 

1300 18.363 

1400 20.289 

1500 22.376 

1600 24.599 

1700 26.95 1 

1800 29.4 17 

1900 3 1.988 

2000 34.669 

2100 37.441 

2200 40.321 

2300 43.33 1 

G:\LPManual\RTMLP9.1 

Compare current calibration to previous calibration 

Click on "Compare calibrations" from menu 

Select previous calibration filename 

Select current calibration filename 

Select temperature scale ("C, OF, or K) - 

Select international temperature scale (ITS-48, ITS-68, ITS-90) 

Enter wavelength (nm) for previous data file 

Enter wavelength (nm) for current data file 

Click on "Run" button 

Enter data file name "XXXXmyy.MYY" 

a. 

b. 

Store comparison data in log file "CMPMMDD.YY" 

Use sample log file on next page: 

Define myy: month and year of previous calibration 

Define MYY: month and year of current calibration 

D22 

Page 4 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP9: Ribbon Filament Lamp Data Reduction 

08- 17- 1995 1 1 :50:32 

Previous calibration data file = 'c:\files\p5 10393 .txt' 

Current calibration data file = 'c:\files\p5 10895.txt' 

Comparing previous to current calibration 

Temp Old [I] New [I] New [I] dI DI/DT Corr. 

655.3nm 655.3nm WL 

["C] ITS-90 ITS-90 ITS-90 ITS-90 

[AI [AI [AI [AI W"C1 

800 11.847 11.843 11.843 0.004 0.0078 0.00 

900 12.724 12.724 12.724 0.000 0.0096 0.00 

1000 13.799 13.800 13.800 -0.001 0.0119 0.00 

1100 15.098 15.100 15.100 -0.002 0.0142 0.00 

1200 16.623 16.626 16.626 -0.003 0.0164 0.00 

1300 18.361 18.363 18.363 -0.002 0.0185 0.00 

1400 20.287 20.289 20.289 -0.002 0.0201 0.00 

1500 22.372 22.376 22.376 -0.004 0.0216 0.00 

1600 24.600 24.599 24.599 0.001 0.0230 0.00 

1700 26.956 26.951 26.951 0.005 0.0242 0.00 

1800 29.423 29.417 29.417 0.006 0.0252 0.00 

1900 31.992 31.988 31.988 0.004 0.0262 0.00 

2100 37.442 37.441 37.441 0.001 0.0283 0.00 

2200 40.329 40.321 40.321 0.008 0.0295 0.00 

2300 43.340 43.331 43.331 0.009 0.0307 0.00 

2000 34.666 34.669 34.669 -0.003 0.0272 0.00 

Comparison data stored in 'CMP0817.95' 

Total change and %Change Radiance stored in 'PSI-393.895' 

Change Total %Change 

Temp. Change Rad. 

ITS-90 ITS-90 

0.5 1 

0.00 

-0.08 

-0.14 

-0.18 

-0.1 1 

-0.10 

-0.18 

0.04 

0.2 1 

0.24 

0.15 

-0.11 

0.04 

0.27 

0.29 

0.5 1 

0.00 

-0.08 

-0.14 

-0.18 

-0.1 1 

-0.10 

-0.18 

0.04 

0.2 1 

0.24 

0.15 

-0.1 1 

0.04 

0.27 

0.29 

0.98% 

0.00% 

-0.1 1% 

-0.16% 

-0.18% 

-0.10% 

-0.08% 

-0.13% 

0.03% 

0.12% 

0.12% 

0.07% 

-0.0 5 yo 

0.0 1 % 

0.10% 

0.10% 

Scale 

Corr. 

["CI 

0.00 

0.00 

0.00 

0.00 

0.00 

0.00 

0.00 

0.00 

0.00 

0.00 

0.00 

0.00 

0.00 

0.00 

0.00 

0.00 

G:\LPManual\RTMLP9.1 

D23 

Page 5 
I I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP9: Ribbon Filament Lamp Data Reduction 

3 1. Use sample comparison data file below: 

G:\LPManual\RTMLP9.1 

P51-393.895 08-17-1995 11:50:49 AM 

Temp ["C] dT ["C] %dL 

800 0.5 1 0.98% 

900 0.00 0.00% 

1000 -0.08 -0.1 1% 

1100 -0.14 -0.16% 

1200 -0.18 -0.18% 

1300 -0.1 1 -0.10% 

1400 -0.10 -0.08% 

1500 -0.18 -0.13% 

1600 0.04 0.03% 

1700 0.21 0.12% 

1800 0.24 0.12% 

1900 0.15 0.07% 

2000 -0.1 1 -0.05% 

2100 0.04 0.01% 

2200 0.27 0.10% 

2300 0.29 0.10% 

Page 6 
I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP9: Ribbon Filament Lamp Data Reduction 

32. Prepare calibration summary sheet 

33. A sample calibration summary sheet is below: 

Radiance Temperature Lab 

Calibration Summary Sheet 

Today's date: December 17, 1997 

NIST Test No: 844/123456-95 Use sample report: 35050c.rfl 

Company: Radiometric Systems Inc 

Contact: John Doe Phone: 301 123-4567 

P.O.#: AB1234 dated January 1,1995 

Test number: 3 5050C Radiance Temperature Standard, Ribbon Filament Lamp 

Test item: One General Electric Tungsten Ribbon Filament Lamp, Model # 30A'24/6, 

Serial # P51 

Temperatures measured: 800 "C to 2300 "C Aligned at 1700 "C 

Standard(s) used: SL20 (7.7788 A, 2.093 V), (Pcos(20)=0.001107, 12/92 TR2 p 123) 

Temperature: 21 "C L 1 "C Relative humidity: 38% f 5% 

Calibration date: 5/24/95 Measurement date(s):5/24/95 TR3 p42 

Data taking program: C:\programs\datatakn\pyro.mak(rtcal. fim 1 0/9/96 

Calibration files: CAL0815.95, P510815.95 

Data reduction program: C :\programs\lampredn\rtred. makl lmpred. frm 5/2 5/95 

Reduction summary: Red0525.95 

Final data filename: P510895.TXT 

Data analysis program:C:\programs\lampredn\rtred.maklcompare.fim 5/25/95 

Reduction summary: CmpO8 17.95 

Previous calibration filename: P5 10393 .TXT 

Comparison filename: P5 1-393.895 

G: \LPManual\RTMLP9.1 

D25 

Page 7 
r ~ ~~ 

Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP9: Ribbon Filament Lamp Data Reduction 

34. Enter data file name "XXXXmyy.MYY" 

a. Prepare history file consisting of Microsoft EXCEL spreadsheet with plots of 

temperature difference from first calibration versus nominal temperature 

G:\LPManual\RTMLP9.1 

D26 

Page 8 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Variable Temperature Blackbody (BB) Alignment 

Written by: Charles Gibson Procedure: RTMLP 10 

Approved by: 

Revised by: 

Date: 

Date: 

Variable Temperature Blackbody (BB) Alignment 

e GAUUUON COLLISION 

1. Align PEP (see RTMLP2) 

2. Remove field stop 

3. 

4. Level aluminum plate (<X) 

5. 

6. 

7. 

8. 

9. Radiometrically center BB 

Remove objective lens aperture, if any 

Use fiber optic light to illuminate BB 

Translate BB along optical axis until center partition is in focus (Z) 

Center BB on optical axis (X and Y) 

Turn on BB (see RTMLPll) 

a. 

b. 

c. 

d. Check centering 

Center <Y about vertical axis 

Center X along horizontal axis 

Repeat i and ii until centered 

1. 

11. 

iii. 

Monitor BB signal on graph logger 

Hold card in front of BB opening 

Check for equal drop-offs when blocking top, bottom, left, and right 

portions of BB opening 

.. 

G:\LPManual\RTMLP 10.1 

D27 

Page 1 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Variable Temperature Blackbody (BB) Operation 

Written by: Charles Gibson Procedure: RTMLP 1 1 

Approved by: Date: 

Revised by: Date: L 

BRIGHT SOURCE 

I BURN I 

ELECTROCUTION 

1. Turn On BB 

a. 

b. 

C. 

d. 

e. 

f. 

g. 

h. 

1. 

j. 

k. 

1. 

m. 

n. 

Open tap water valve 1/8 turn 

Check that blue box flow rate is about 2 gpm 

Open chilled water valves 

1. 

11. Open return valve fully 

Press reset button on blue water switch box to select chilled water 

Check that blue box flow rate is about 5 gpm 

Open argon cylinder valve fully 

Turn on argon alarm and check that it trips at 10 cfh 

Purge BB using argon flow rate of 70 cfh 

1. 

11. 

iii. 

iv. 

Repeat step h 5 times 

Reduce argon flow rate to 10 cfh 

Check that BB housing is cool and that argon is flowing 

Insert correct detector filter for initial set point 

1. 

11. 

iii. 

iv. 

Switch control mode to [MANUAL] 

Turn potentiometer to 0 

Open supply valve 1/4 turn .. 

Cover both BB openings for 5 s with your hands 

Uncover one end and wait 5 s 

Cover both BB openings for 5 s with your hands 

Uncover other end and wait 5 s 

.. 

Filter 0,700 OC to 1300 OC, Low with insulation (LIN) 

Filter 1, 1300 OC to 1800 OC, Medium (MED) 

Filter 2, 1800 OC to 2500 OC, High (HI) 

Filter 3,2500 OC to 3100 OC, Extra High(XH) 

.. 

G:\LPManual\RTMLP 1 1.1 

D28 

Page 1 
~~ ~~ 

Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLPl 1 : Variable Temperature Blackbody (BB) Operation 

0. Press [START], [WATER ON], and [RUN] buttons 

1. 

Turn potentiometer slowly until voltmeter reads between 150 VAC and 200 VAC 

(sets BB below 1300 "C) 

Note that BB does not control chilled water flow, because automatic BB 

shutoff switch has been disabled 

p. 

2. Operate BB 

a. Run BB control program 

1. 

11. 

111. Enter measurement direction 

'0' to run high to low 

'1' to run low to high 

Program is BBPROG.PRG in BetterBasic 

Enter BB at DOS prompt 

(1) 

(2) 

(1) IC' for "C 

(2) 'F' for "F 

.. 

... 

iv. Enter set point unit 

v. re Enter temperature range 

(1) LOW 

(2) LIN 

(4) HI 

(5) XH 

(3) MED 

vi. 

Press [Shift SI to enter initial set point 

Adjust potentiometer until temperature is 20 "C above set point 

Switch control mode to [PC] to maintain set point 

Insert correct filter and press [Enter] 

b. 

c. 

d. 

WARNING! DO NOT INCREASE SET POINT BY STEPS LARGER THAN 20 "C TO 

REDUCE DAMAGE TO BB 

e. Select new set point (set point is in "C or "F depending on set point unit selected) 

1. 

11. 

Press [Shift SI to enter set point 

Use numeric keypad to increment set point 

(1) Press increment key 

.. 

(a) 

(b) 

(c) 

Press 7 for 100 "C 

Press 4 for 10 "C 

Press 1 for 1 "C 

G:\LPManual\RTMLP 1 1.1 Page 2 

D29 
I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLPll : Variable Temperature Blackbody (BB) Operation 

(d) 

Press direction key to set new set point 

(a) 

(b) 

Press 0 for 0.1 "C 

Press 8 to increase set point 

Press 2 to decrease set point 

Use default set points depending on measurement direction 

(1) 

(2) 

f. Pause program (suspending BB control) if new set point is not in current range 

1. 

Use high to low default set points 

(a) 

(b) 

(c) 

(d) 

Use low to high default set points 

(a) 

(b) 

(c) 

(d) 

Select XH for 2500 "C 

Select HI for 2300 "C 

Select MED for 1800 "C 

Select LOW for 1300 "C 

Select LOW for 800 "C 

Select MED for 1300 "C 

Select HI for 1800 "C 

Select XH for 2500 "C 

(2) 

.. 

11. 

111. 

Switch control mode to [MANUAL] if new set point is not default value 

Loop program step 2.a.v. (see ") ... 

3. Use EMERGENCY TURN OFF procedure when necessary 

a. 

b. 

a. 

b. 

c. 

d. 

e. 

f. 

g. 

h. 

i. Close argon cylinder valve 

jPress [EMERGENCY STOP] button on power supply (chilled water and argon 

will continue flowing) 

Continue with steps 4.b. to 4.j. 

Switch control mode to [MANUAL] 

Turn to potentiometer to 0 

Press [EMERGENCY STOP] button on power supply (chilled water and argon 

will continue flowing) 

Switch off main breaker on wall 

Wait until furnace has stopped glowing 

Close chilled water supply valve 

Close chilled water return valve 

Close cold water supply valve 

Close argon flow meter valve 

4. Turn Off BB 

G:\LPManual\RTMLP 1 1.1 Page 3 

D30 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Disappearing Filament Optical Pyrometer Alignment 

Written by: Charles Gibson Procedure: RTMLP 12 

Approved by: Date: 

Revised by: Date: 

Disappearing Filament Optical Pyrometer Alignment 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

Align BB (see RTMLP 10) 

Check that objective lens and eye piece are clean 

Check batteries 

Zero galvanometer 

Use post with magnetic base, height adjustment, and angle bracket to mount pyrometer 

Position post and level angle bracket mounting surface 

Mount pyrometer to angle bracket 

I COLLISION I ~ ~~ 

Use joystick to move BB to test pyrometer position 

Use fiber optic light to illuminate BB 

Set pyrometer at measuring distance from BB center partition 

a. 

b. 

Adjust pyrometer eye piece to focus on illuminated lamp filament 

Focus pyrometer on center partition 

Adjust pyrometer and/or move BB so that pyrometer views down center of BB cavity 

Check distance 

Adjust pyrometer and/or move BB so that pyrometer views down center of BB cavity 

Record table position 

Repeat for other test pyrometers 

Use distance of 30.2 cm from center partition to end of graphite extension tube 

Measure distance from front surface of objective lens holder to extension tube (for 

1 m, distance is 69.8 cm) 

G:\LPManual\RTMLP 12.1 Page I 

D3 1 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Radiation Thermometer (RT) Alignment 

Written by: Charles Gibson Procedure: RTMLP 13 

Approved by: Date: 

Revised by: Date: 

Radiation Thermometer (RT) Alignment 

1. 

2. 

3. 

4. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

Align BB (see RTMLP 10) 

Check that objective lens and eye piece are clean 

Use post with magnetic base, height adjustment, and angle bracket to mount RT 

Position post and level angle bracket mounting surface 

Mount RT to angle bracket 

I I I COLLISION I 

Use joystick to move BB to test RT position 

Use fiber optic light to illuminate BB 

Set RT at measuring distance from BB center partition 

a. Use distance of 30.2 cm from center partition to end of graphite extension tube 

b. Measure distance from front surface of objective lens holder to extension tube (for 

1 m, distance is 69.8 cm) 

c. Measure distance from alignment mark to extension tube for Land Cyclops RT 

(for 1 m, distance is 69.8 cm) 

Adjust RT eye piece to operator's eye 

Focus RT on center partition 

Adjust RT and/or move BB so that RT views down center of BB cavity 

Check distance 

Adjust RT and/or move BB so that RT views down center of BB cavity 

Record table position 

Repeat steps 2 to 14 for each test RT 

Turn on BB (see RTMLPll) 

Check centering of each test RT 

a. 

b. 

c. 

Monitor RT signal on graph logger or look at RT display panel 

Hold card in front of BB opening 

Check for equal drop-offs when blocking top, bottom, left, and right portions of 

BB opening 

G:\LPManual\RTMLP 13.1 Page 1 

D32 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Radiation Thermometer (Optical Pyrometer) 

Calibration Procedure 

Written by: Charles Gibson Procedure: RTMLP 14 

Approved by: Date: 

Revised by: Date: 

Radiation Thermometer (Optical Pyrometer) Calibration Procedure 

1. Review calibration summary 

a. 

b. 

c. 

Run general data taking program (see RTMLP1) 

Align standard lamp (see RTMLP6) 

Align BB (see RTMLP 10) 

Align standard lamp, BB, and test RTS 

Measure from 2700 "C to 800 "C in 100 "C steps 

Repeat 2300 "C, 1900 "C, 1500 "C, 1300 "C, 1100 "C, and 800 "C 

2. 

3. 

4. 

5. Align RTS (see RTMLP13) 

6. Run calibration program 

a. 

b. Select "Radiation thermometer" button 

C. Enter data filename 

d. Enter test filename suffix$ 

1. 

e. Select Yes and use suggested ranges (PMT high voltage and amplifier ranges are 

part of Rtca1.Ji.m program) 

f. Click on "Start" button 

g. Enter data on Software.Ji.m 

Enter lamp and blackbody data 

(1) 

(2) Select "Usel' button 

(3) Enter lamp position 

(4) Enter lamp name 

(5) Select "Reference" button 

(6) 

(7) Enter power supply number 

Click on "Calibrations" from Hardware. frm menu to load Rtca1.Ji.m 

Create test filenames from names on SofhYare.jFm 

1. 

Enter data for reference and BB 

Enter lamp current (not necessary because lamp currents are 

automatically read from lamp monitoring computer) 

G:\LPManual\RTMLP 14.1 Page 1 

D33 
I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP14: Radiation Thermometer (Optical Pyrometer) 

Calibration Procedure 

h. 

1. 

jk. 

1. 

m. 

n. 

P. 

9- 

r. 

0. 

S. 

t. 

.. 11. Enter radiation thermometer data 

(1) 

(2) Select "Use" button 

(3) Enter RT name 

(4) Enter source table position 

(5) 

(6) 

(7) 

(8) Select instrument wavelength (nm) 

Enter data for check standard and test RTS 

Enter digital multimeter channel to read signal 

Enter RT type (0 for optical pyrometers and R for radiation 

thermometers) 

Enter output type (P for panel or scale, D for digital, A for analog) 

iii. Select temperature scale 

iv. Select measurement wavelength [nm] 

v. 

vi. 

vii. Select lamp type 

viii. Select detector channel 

Click on "Save Configuration" button 

Select "Continue" button to return to RtcaZ.fi.m 

Enter Standard temperature in "C in input box 

Enter Nominal radiance temperature in input box 

Read lamp currents automatically 

Enter BB set point 

Wait 5 min for BB to stabilize 

Move source table to reference source and measure hll scale signal 

Move source table to dark signal position and measure dark signal 

Move source table to BB and measure full scale signal 

Move source table to dark signal position and measure dark signal on BB 

amplifier range if reference and BB amplifier ranges are different 

Repeat steps o to r ''number of repeats'' times 

Enter emissivity correction for test RT wavelength 

1. 

iii. 

iv. 

Enter number of repeats (number of tesdstandard measurements) 

Enter number of readings (number of readings per DMM trigger) 

Enter 0 for 655.3 nm 

Enter 1 for 900 nm 

Enter 2 for 1000 nm 

Enter 3 for true temperature 

.. 

11. 

G:\LPManual\RTMLP 14.1 

D34 

Page 2 
I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLP14: Radiation Thermometer (Optical Pyrometer) 

Calibration Procedure 

u. Move BB in fiont of each RT and take reading 

1. 

11. 

iii. 

iv. 

Read RTs with digital outputs 3 times 

Read RTs with analog outputs 3 times 

Enter display value for RTs with digital display panels 

Read OPs matching from bright to dark and then fiom dark to bright 

(1) Enter scale value or press [Enter] to read output signal 

(2) Read 2 sets 

Select next action and then select "Continue" button 

i. Repeat measurement with no changes 

11. Measure with new temperature 

iii. Measure with new software changes 

iv. Stop measurements 

Repeat xxii for each measurement point 

.. 

V. 

.. 

w. 

Store calibration data in log file "CALMMDD.YY" 

Use sample log file on next page: 

7. 

8. 

G:\LPManual\RTMLP 14.1 

D35 

Page 3 
I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLPl4: Radiation Thermometer (Optical Pyrometer) 

Calibration Procedure 

Date 12-13-1996 Time 9:48:10 AM 

File Name = CAL 12 13.96 

PMT Detector 

Wavelength = 655.3 nm 

PMT HV = 449 V NRDS = 5 Integration Time = 8.35 s 

Nominal Rad Temp = 1800 "C 

Name SL20 TGBB 

Rad. Temp 

Current 

Sp. Rad. 

Ratio 

Std. Ratio 

Amp Range 

Full Scale 

Dark Sig. 

Mean 

Std(Mean) 

Range Cf. 

ss Cf. 

Corr. Mean 

Position # 

Table Pos. 

1254.96 "C 

7.7788 A 

5.690E+02 

l.OOOE+OO 

0.06% 

9 

1.016E+00 *O.OO% 

1.016E+00 ~0.00% 

1.01 5E+00 *O.OO% 

1.01 5E+00 

0.04% 

l.OOOE+OO 

1.014E-01 

1 

37500 

1.5 1 OE-04 

9.9858E-02 

1799.01 "C 

2.472E+04 

4.3 44E+O 1 

0.05% 

8 

4.41 1E+00 *O.OO% 

4.41 1E+00 *0.01% 

4.410E+00 *0.01% 

- 1.166E-04 

4.4 1 1 E+OO 

0.01% 

l.OOOOE+OO 

9.987E-01 

4.405E+00 

3 

127500 

Position CY52 TEST PYRO # 1 

Mean = 1804.0 "C 

Reading # 1 1804 "C 0.0 "C 

STD = 0.0 "C 

Temperature Set for THERMOGAGE = 1800 "C 

Measured Temperature at 655.3 nm = 1799.01 "C 

Calculated Temperature at 655.3 nm = 1799.01 "C 

Mean 1804.0 "C 

Test Std 0.0 "C 

rest Corr. -6.0 "C 

G:\LPManual\RTMLP 14.1 Page 4 

D36 
I Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Procedure RTMLPl4: Radiation Thermometer (Optical Pyrometer) 

Calibration Procedure 

9. 

10. 

Store RT data in test file "XXXXMMDD.YY" 

Use sample test data file below: 

c:\PYRO\CY521213.96 

Standard used is SL20 at 1254.96 "C 

Temperature in "C 

Temperature measured at 655.3 nm Temperature calculated at 1000 "C 

Tnom Tbb Tcorr CY52 Std Corr 

12-13-1996 9159106 AM 

1800 1799.01 1797.98 1804.0 0.0 -6.0 

1700 1699.18 1698.26 1704.5 0.0 -6.2 

1600 1599.47 1598.64 1603.0 0.0 -4.4 

1500 1499.31 1498.56 1502.0 0.0 -3.4 

1400 1399.24 1398.57 1401.0 0.0 -2.4 

1300 1299.30 1298.71 1302.0 0.0 -3.3 

1200 1199.36 1198.85 1201.0 0.0 -2.2 

1100 1099.34 1098.89 1100.5 0.0 -1.6 

1100 1099.25 1098.80 1100.5 0.0 -1.7 

1000 999.15 998.76 1000.0 0.0 -1.2 

1 1. Reduce data (see RTMLP 15) 

G:\LPManual\RTMLP 14.1 Page 5 

D37 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

Radiation Thermometer (RT) Data Reduction 

Written by: Charles Gibson Procedure: RTMLP 1 5 

Approved by: Date: 

Revised by: Date: 

Radiation Thermometer (RT) Data Reduction 

1. 

2. 

3. Print out test files 

4. 

5. 

6. 

7. Sort data 

8. 

9. Plot data 

10. 

1 1. 

Print out test file for RT check standard 

a. Veri@ that RT check standard values are within uncertainty 

Print out test file for BB RT check standard 

a. VeriQ that BB RT check standard values are within uncertainty 

Look in lab notebook and document any changes on print out and then edit file 

Load EXCEL and open test file 

Separate data by range or filter 

Calculate mean and standard deviation of repeats 

Save in data file "XXXXMMYY.XLS" 

Use sample data file below: 

c:\PYRO\TEST1007.96 

12. Use, for repeats, values of blackbody temperature (T,,,), test RT reading (TEST), and test 

RT correction (Corr) that best represents mean of repeats so that actual reading is 

reported 

13. Save data in text file (tab delimited) "XXXXMMYY.TXT" 

G:\LPManual\RTMLP15.1 Page 1 

D38 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

I Procedure RTMLP15: Radiation Thermometer (RT) Data Reduction I 

14. Use sample file below: 

Test1 096.TXT 1 1/4/96 

Tnom Tcorr TEST Corr Filter 

["CI ["CI ["CI ["C] Clear 

800 800.3 803 -2.7 

900 898.7 900.5 -1.8 

1000 998.7 1000 -1.3 

1100 1098.7 1100 -1.3 

1200 1198.8 1200 -1.2 

15. Prepare calibration summary sheet 

16. Use sample calibration summary sheet on next page: 

G:\LPManual\RTMLP15.1 

039 

Page 2 
Optical Technology Division (844) 

Radiance Temperature Lab 

Calibration Summary Sheet 

Today's date: December 17, 1997 

NIST Test No: 844/123456-95 Use sample report: 35070sdc.lum 

Company: Radiometric Systems Inc 

Contact: Joe Calibration Phone: 301 123-4567 

P.O.#: AB1234 dated January 1,1995 

rest number: 350703 Special Test of Radiation Thermometer 

rest item: One Minolta-Land Infrared Thermometer, Model # Cyclops 52, Serial # 0000000 

Wavelength = 1000 nm 

rarget size: 5.6 mm 

Distance: 100 cm from alignment mark 

Focus: 1 meterclear and dark lenses (sn L1) 

remperatures measured: 800 "C to 2500 "C 

800 "C to 1200 "C with clear filter 

1100 "C to 2500 "C with dark filter 

Itandard(s) used: SL20 (7.7788 A / 2.093 V ), (Pcos(28)=0.001107, 12/92 TR2 p 123) 

Land Cyclops 52 pyrometer, Serial no.: 202681 

Thermogage 7000-1 pyrometer, Serial no.: 5 127 

remperature: 21 "C + 1 "C Relative humidity: 38% + 5% 

Zalibration date: 2/16/96 Measurement date(s):2/15-16/96 TR3 p79 

3ata taking program: C :\programs\Lmpredn\pyro .maklrtcal. fim 1 0/9/96 

Calibration files: Cal1007.96, Test1007.96 Tgbb1007.96 

lata reduction program: Excel 7.0 

Data reduction file: Test1 096.~1s Final data file: Test 1096.m 

G:\LPManual\RTMLP 1 5.1 Page 3 
Optical Technology Division (844) 

Radiance Temperature Measurements Laboratory Procedure 

I Procedure RTMLP15: Radiation Thermometer (RT) Data Reduction 

17. Print out test file for RT check standard 

a. Prepare history file consisting of Microsoft EXCEL spreadsheet with plots of 

temperature difference from first calibration versus nominal temperature 

G:\LPManual\RTMLP 1 5.1 

D4 1 

Page 4 
Appendix E: How to Request Radiance Temperature Measurement Services 

1. Prepare a purchase order with the following: 

a. Company name and address 

b. Contact person's name and phone number. 

c. Billing address 

d. Service ID number requested (include range and points) 

e. Test fee 

f. Address to ship test item 

g. Return shipping instructions (prepay and add, COD, charge to account with shipper) 

i. the test fee does not include shipping costs 

ii. customers are responsible for all shipping costs 

iii. If no instructions are given, NIST will return the test item by common carrier, collect, 

and uninsured. 

2. Send the purchase order to: 

National Institute of Standards and Technology 

Calibration Program 

Building 820, Room 232 

Gaithersburg, MD 20899-0001 

Tel.: (301) 975-2002 

E-mail: calibrations@enh.nist.gov 

FAX: (301) 869-3548 

3.Send the test item@) to: 

Charles Gibson 

NIST 

Building 221 / Room B208 

Gaithersburg, MD 20899-0001 

Tel.: (301) 975-2329 

E-mail: cgibson@nist.Pov 

WWW: http://physics.nist.gov/Divisions/Div844/staff/Gp3/gibson.html 

FAX: (301) 869-5700 

Radiance temperature calibrations are performed in February, May, August, and November. 

Requests for calibration services are scheduled after the receipt of a purchase order. 

NIST policy requires prepayment of all calibration services performed for non-U.S. 

organizations. Please contact the Calibration Program office to arrange payment. 

El 

*U.S. (KIVE- PRINTINQ OFFICE:1998-433-235~93205 
THE SP 250 SERIES ON NlST MEASUREMENT SERVICES* 

SP 250-1 

SP 250-2 

SP 250-3 

SP 250-4 

SP 250-5 

SP 250-6 

SP 250-7 

SP 250-8 

SP 250-9 

SP 250-10 

SP 250-11 

SP 250-12 

SP 250-13 

SP 250-14 

SP 250-15 

SP 250-16 

SP 250-17 

SP 250-18 

SP 250-19 

SP 250-20 

Spectral Radiance Calibrations 

PB87179883 

Far Ultraviolet Detector Standards 

PB87227609 

Radiometric Standards in the Vacuum 

Ultraviolet 

PB87227625 

Fricke Dosimetry in High-Energy Electron Beams 

PB88110374 

Alpha-Particle Calibrations 

PB88168620 

Regular Spectral Transmittance 

PB88108550 

Radiance Temperature Calibrations 

PB88123674 

Spectral Reflectance 

PB88109905 

Calibration of Beta-Particle-Emitting 

Ophthalmic Applicators 

PB88108535 

Radioactivity Calibrations with the "4n" 

Gamma Ionization Chamber and Other 

Radioactivity Calibration Capabilities 

PB88123708 

Dosimetry for High Dose Applications 

PB88201587 

Neutron Personnel Dosimetry 

PB87227617 

Activation Foil Irradiation with Californium 

Fission Sources 

PB88217443 

Activation Foil Irradiation by Reactor Cavity 

Fission Sources 

PB88217435 

Photometric Calibrations 

PB88153747 

Calibration of X-Ray and Gamma-Ray 

Measuring Instruments 

PB88211826 

The NBS Photodetector Spectral Response 

Calibration Transfer Program 

PB88201595 

Neutron Source Strength Calibrations 

PB88211818 

Calibration of Gamma-Ray-Emitting 

Brachytherapy Sources 

PB89193858 

Spectral Irradiance Calibrations 

PB88123781 

SP 250-21 

SP 250-22 

SP 250-23 

SP 250-24 

SP 250-25 

SP 250-26 

SP 250-27 

SP 250-28 

SP 250-29 

SP 250-30 

SP 250-31 

SP 250-32 

SP 250-33 

SP 250-34 

SP 250-35 

SP 250-36 

SP 250-37 

SP 250-38 

SP 250-39 

SP 250-40 

Calibration of Beta-Particle 

Radiation Instrumentation 

PB88201579 

Platinum Resistance Thermometer 

Calibrations 

PB88138367 

Liquid-in-Glass Thermometer 

Calibration Service 

PB89128888 

Standard Cell Calibrations 

PB88123690 

Calibration Service for Inductive 

Voltage Dividers 

NBS Phase Angle Calibration Services 

PB88225636 

AC-DC Difference Calibrations 

PB892222616 

Solid-state DC Voltage Standard Calibrations 

PB88168703 

Traceable Frequency Calibrations 

PB88168364 

GOES Satellite Time Code Dissemination: 

Description and Operation 

PB88168760 

Mass Calibrations 

PB89153894 

A Calibration Service for 30 MHz 

Attenuation and Phase Shift 

PB88238324 

A Calibration Service for Voltage Transformers 

and High-Voltage Capacitors 

PB882252903 

High Vacuum Standard and Its Use 

PB89193841 

The Calibration of Thermocouples 

and Thermocouple Materials 

PB89209340 

A Calibration Service for 

Current Transformers 

PB91216770 

Photometric Calibrations 

PB97148472 

NlST Leak Calibration Service 

PB92149772 

NlST Pressure Calibration Service 

PB94164043 

Absorbed-Dose Calibration of 

Ionization Chambers in a 

'%20 Gamma-Ray Beam 

SN003-003-03034-1 $2.00 

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