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A11105 ^77723

NBS TECHNICAL NOTE 594-14

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U.S. DEPARTMENT OF COMMERCE/National Bureau of Standards

Optical Radiation Measurements:

High Pressure Sodium Discharge

Lamp Characterization for Use

as Standards of Geometrically

Total Luminous Flux

Minggao He and Robert J. Bruening
rheNational Bureau of Standards1 was established by an act of Congress on March 3, 1901. The

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Optical Radiation Measurements:

High Pressure Sodium Discharge

Lamp Characterization for Use

as Standards of Geometrically

Total Luminous Flux

Minggao He

Fudan University

Shanghai, China

Robert J. Bruening

Center for Radiation Research

National Measurement Laboratory

National Bureau of Standards

Gaithersburg, MD 20899

August 1988

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U.S. DEPARTMENT OF COMMERCE, C. William Verity, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director
National Bureau of Standards Technical Note 594-14

Natl. Bur. Stand. (U.S.), Tech. Note 594-14, 49 pages (Aug. 1988)

CODEN: NBTNAE

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1988

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402
Abstract

The stability of commercial 400W high pressure sodium lamps has been

studied to allow the selection of lamps that produce a stable luminous

flux on relighting. The properties of the lamps have been studied during

the first minutes of starting, their output on relighting in place, and

their output after 100' s of hours burning. Lamps have been selected that

repeat to + 1% on relighting, and are expected to remain that stable over

a life of about 450 hours. The lamps have been calibrated for total

luminous flux by sphere comparison, with an uncertainty of +4.6%. These

lamps will be used as working standards, and goniometric measurements

will be made to reduce the uncertainty.

Commercial products — materials and instruments — are identified in this

document for the sole purpose of adequately describing experimental or test procedures. In no event does such identification imply

recommendation or endorsement by the National Bureau of Standards of a particular product; nor does it imply that a named material or instrument

is necessarily the best available for the purpose it serves.

1X1

TABLE OF CONTENTS

Page

1

.

Introduction 1

2. Development of HPS lamp 1

3. The physical properties of HPS lamps 2

3.1 Lamp construction 2

3.2 Starting characteristics 4

3.3 Design parameters and their effect on luminous

efficacy and spectral distribution 4

3.4 Design parameters' effects on life of lamp 9

4. Method of selecting stable lamps 10

5. Description of the measurements 12

5.1 General 12

5.2 Lamp operation 13

5.3 Integrating sphere properties 14

5.4 Spectroradiometer properties and measurement

techniques 15

5.5 Measurements made and analysis of the data 18

6

.

Results of the measurements 20

6 .

1

Sphere measurements of total luminous flux 20

6.2 Ambient temperature effects on luminous flux 21

6.3 Lamp wattage influence on luminous flux 21

6.4 Repeatability on relighting 23

6.5 Stability of lamps as a function of lamp

burning time 23

7

.

Summary 24

Tables 32

References 43

1 . Introduction

The National Bureau of Standards has provided standards for

measurements of light for much of its history. Photometric standards

have been issued in the form of calibrated incandescent tungsten lamps.

Such lamps were quite satisfactory for many years when the bulk of

lighting was provided by tungsten illumination, having similar spectral

properties to the standards. Over the years, discharge lamps have come

into very common use. However, such lamps have spectral distributions

that are quite different from that of a tungsten lamp. Calibration of

the luminous flux produced by a discharge lamp by direct photometric

comparison to a tungsten lamp standard can not be made with the same accuracy as that available for tungsten lamp to tungsten lamp

comparisons. Therefore, modern lighting laboratories calibrate discharge

lamps by making spectral measurements of the lamp output. The lighting

industry has asked the NBS to produce standards which would be calibrated

spectrally, and to provide a discharge type of calibrated lamp which more closely matches the type of lamp and method of calibration used in

industry. A high pressure sodium discharge lamp (HPS) was chosen for

this standard. The stability of the light output of 400W HPS lamps has

been studied, and as a result, methods have been developed to select the

most stable lamps for calibration as standards.

2. Development of HPS lamp

High pressure sodium (HPS) lamps provide an economical source of

illumination. Introduced by Louden and Schmidt [1] in 1965, such lamps

generate light by an electric discharge in sodium vapor. They convert

electricity into light more efficiently than incandescent, fluorescent,

or other discharge light sources, producing the highest luminous efficacy

of all short arc high intensity discharge (HID) light sources. The

luminous efficacy of HPS lamp can be as high as 150 lm/W [2] . This is

six times the efficacy of typical incandescent lamps, over twice the

efficacy of high pressure mercury lamps, and about 50% higher than the

efficacy of either metal halide or fluorescent lamps. Over the twenty

years since their initial development, the HPS lamp has been improved by

research into the basic properties of electrical discharge in sodium

vapor at high pressures. Comprehensive review papers on HPS lamps [3, 4,

5, 6] have reported on both basic and engineering aspects of the

development. In such lamps, the high pressure sodium vapor discharge arc operates at temperatures of up to 1500 C C, producing optical radiation

with a broadened spectrum near the peak of the human eye photopic vision.

With continued development of new materials and technology, this

lamp may come close to its theoretical maximum efficacy of 385 lm/W. For

a conventional 400W HPS lamp, the efficacy including ballast losses, is

presently about 120 lm/W. Like other HID lamps, the efficacy increases

with increasing wattage. They have a very long life, about 24,000 hours

on average, and a correlated color temperature of about 2100 K. Unlike

the metal halide lamps , the flux output of HPS lamps is not affected by

the burning position or tilt angle. The major hindrance to wide use of
HPS lamps is their poor color rendering of everyday objects, since HPS

lamps have a color rendering index (CRI) of approximately 25 [7].

HPS lamps have become the most popular -HID source for general

outdoor lighting applications such as roadway lighting, tunnel lighting, area lighting and building floodlighting. HPS lamps are also rapidly

becoming the economical choice for many stadium lighting needs. For

indoor lighting, there is an increasing interest in their application to

commercial, industrial, school, and sports areas where high efficacy is

of prime importance and color rendition is a secondary consideration.

There are proven techniques that will improve the color rendering

index of HPS lamps. These techniques include increasing the sodium

operating pressure to emphasize the self -absorption and re-emission of

the D- lines, using additives in the lamp to provide spectra other than

that from sodium, or exciting higher energy levels of the sodium vapor to

obtain emission at wavelengths other than the D-lines [3].

In the past years, using these methods, lamp manufacturers have

developed some ultra-HPS lamps with an improved color rendering index,

but only at the expense of luminous efficacy. At present, new HPS lamps

with superior color rendering properties and high efficacy have been

developed by several researchers. Bhalla, et al , [8] realized the new

250W HPS lamps with a CRI of 65 and an efficacy of 100 lm/W, and Otani

,

et al , [2] developed a new type of retrofit HPS lamp which achieves an improved CRI of 50-60 with high luminous efficacy of 105-130 lm/W (220W660 W) . Akutsu, et al, [9] described their improvement of new 150W400W HPS lamps with CRI of 78-85, a luminous efficacy of 40-60 lm/W, an average life time of 9,000 hrs .

, and a correlated color temperature

between 2500K and 2800K, close to that of an incandescent lamp. Because

of their higher CRI, higher efficacy, and longer life than incandescent

lamps, the new HPS lamps have achieved widespread commercial importance

for many lighting purposes where color rendition (illuminating quality)

are needed. They provide comfortable lighting environments with an energy-saving substitute for incandescent lamps.

3 . The physical properties of HPS lamps

Extensive theoretical and experimental data on HPS lamps have been

reported in other publications, and that information need not be reviewed

extensively here. However, those properties that play a role in the

stability of the spectral radiant flux produced by a lamp will be

discussed to provide a foundation for an explanation of the measurements

which were made.

3 . 1 Lamp construction

Because sodium vapor, operating at a high temperature, has a highly

corrosive effect on ordinary glass or quartz, the high pressure sodium

discharge was solely of theoretical interest for many years. The

development of a translucent polycrystalline alumina (PCA) tube,

resistant to sodium attack at high temperatures, and with high optical
transmittances in the visible range, made the HPS lamp technically

feasible. Development of techniques for sealing sintered PCA ceramic

tubes to carry electrodes and lead-in wires made it possible to actually

manufacture such a lamp.

The heart of a conventional HPS lamp is a PCA tube filled with a sodium/mercury amalgam and an inert gas, usually xenon, used for starting

the arc. A typical construction of a HPS lamp is illustrated in Fig. 1. The arc tube is mounted in an evacuated outer borosilicate glass bulb to

isolate the tube from the ambient environment. The arc tube transmits

>90% of visible radiation and can withstand the corrosive attack by hot

sodium vapor. The PCA tube and outer glass envelope can withstand

temperatures as high as 1600°C and 400 C C, respectively. A getter

material is used in the glass bulb to trap any impurities that may be

released from the glass, arc tube and tube mounting structure. The

diameter of the HPS arc tube is much smaller than that of mercury or metal halide lamps, and does not have a starting electrode inside the

tube like other HID lamps. Therefore, the ballast for a HPS lamp

contains a special starting circuit capable of ionizing the xenon gas,

such as a low energy, high voltage pulse on each power line cycle or half

cycle.

Borosilicate Sodium Vapor Exhaust Tube with

Glass Discharge Amalgam Reservoir Mogul Base

"V- w >s

Seal of

Arc Tube Vacuum

LujjF

Getter

Polycrystalline Coated Tungsten

Alumina Arc Tube Electrodes

Ballast

Input

Power

Fig 1. Typical construction of a High Pressure Sodium Discharge lamp
3 . 2 Starting characteristics

When first started, the discharge is predominantly caused by the

xenon gas. As the temperature starts to rise, and mercury vapor pressure

builds up in the arc tube, more and more sodium is excited and the lamp

color shifts from the bluish-white of ionized mercury and xenon to the

yellow of sodium, and finally to golden-white produced by a large

continuum spectrum in the red and green regions and a smaller amount in

the blue and violet regions.

3 . 3 Design parameters and their effect on luminous efficacy and

spectral distribution

The luminous efficacy of a HPS lamp depends upon the following

design parameters:

(1) the sodium and mercury vapor pressures (which vary with the

ratio of sodium to mercury, the amount and the operating

temperature of the amalgam)

;

(2) the vapor pressure of the xenon;

(3) the discharge tube bore, length, wall thickness and tube

materials

;

(4) the tube wall loading (the lamp wattage divided by the effective

surface area of the tube)

;

(5) the electrode construction and emitter materials.

An optimally designed 400W HPS lamp has the following design

parameters [5]: the sodium, mercury and xenon pressures in the operating

lamp are about 10^ Pa, 8X10^ Pa and 2X10^ Pa, respectively; the inner

diameter of the arc tube, the electrode spacing, and the tube wall

thickness are about 7.5 mm, 82 mm and 0.6 mm, respectively; and the wall

loading of the arc tube is about 20 W/cm , that is, just below the

critical value for failure of the arc tube. The wall temperature of the

discharge tube is mainly determined by the wall loading. The luminous

efficacy increases with increasing tube diameter at constant wall

temperature. A higher wall loading results in a higher luminous efficacy

at constant diameter.

Like the metal halide lamps, HPS lamps contain an excess quantity of

liquid amalgam, which is located behind the electrodes. During lamp

operation, a small quantity of sodium/mercury amalgam is partially

vaporized. The excess amalgam remains condensed in the coolest part of

one end of the arc tube. The liquid amalgam can replenish any sodium

lost from the arc discharge, thereby prolonging the life and somewhat

stabilizing the electrical parameters of the HPS lamp.

The optical spectral power distribution of the HPS lamp is partly
determined by the vapor pressures of sodium and mercury, which are governed in turn by the ratio of sodium/mercury in the amalgam and the

temperature of the coolest part of the arc tube. The color rendition and

the luminous efficacy of an HPS lamp depend markedly on the shape of the

spectrum in the region of the self -reversed sodium D- lines. A typical

relative spectral power distribution curve is illustrated in Fig. 2 on

the next page. The coolest part of the arc tube serves as a reservoir of

the liquid amalgam which is kept at an optimum temperature for the

desired characteristics of the lamp. The temperature of the amalgam may

vary from approximately 600°C to 750°C, depending on the manufacturer.

Some manufacturers place the amalgam reservoir external to the arc tube

(see Fig. 1), but others use an inside corner of the tube. The partial

vapor pressure of the sodium will depend upon the composition of the

liquid phase at the operating temperature. If some radiation is

reflected back to the reservoir, it will increase the temperature of the

coolest part of the arc tube and then, the light output of the HPS lamp

will change. If the amalgam temperature changes, the lamp voltage will

change proportionately if not controlled. Therefore if stable flux is

desired, the power supplied to the lamp must be well controlled by

regularly adjusting the input voltage.

For a conventional HPS lamp, the ratio of sodium/mercury amalgam,

the dimensions of the arc tube, the xenon pressure, and the wall loading

are kept constant. However, the composition and the temperature of the

amalgam will be changed by the normal blackening of the ends of the arc tube and/or the loss of sodium during lamp life. This will affect the

stability of the light output of the lamp. If the sodium vapor pressure

in an HPS lamp is increased by increasing the cool spot temperature, the

separation of the intensity maxima on either side of the self-reversed Dlines, AA, (see Fig. 3) will be increased. If the sodium vapor pressure

is increased with a corresponding decrease in mercury vapor pressure, the

peaks of the spectral curve will be decreased asymmetrically. The

maximum luminous efficacy is produced at a certain sodium/mercury ratio.

For 400W HPS lamps, the mole fraction of sodium in amalgam is within the

range of 0.625 - 0.76. The maximum efficacy is reached when a (25°C)

sodium mole fraction of 0.70 is used at an amalgam temperature of 640 °C

[10].

3.3.1 Electric power dissipation mechanisms

All theoretical studies of the high pressure sodium vapor discharge are based on equating the input electric power to various power

dissipation mechanisms [4,5,11]. For a 400W HPS lamp about 50 - 60

percent of the input power is transformed into radiant power, about 118W

into the visible, about 80W into the infrared, and about 2W into the

ultraviolet. About 5 percent of the input power is lost at the

electrodes, and the rest is lost by heat-conduction [6, 12]. It is

necessary to establish and solve the energy balance equation of the

input-output process in order to predict the performance of arcs in high

pressure sodium vapor.
0)

'S3

<0 Ul rf m 0J n <i r=3 C3 H a

Fig 2. Optical spectral power distribution of a high pressure sodium

discharge lamp, relative radiance versus wavelength in nm.
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Fig 3. Expanded optical spectral power distribution of peaks in the

region around the self reversed sodium D- lines, relative radiance versus wavelength in ran.

3.3.2 Optical spectrum parameters

3.3.2.1 Effects of the relative Hg and Na pressures

The broadening mechanisms of sodium D- lines include the

resonance broadening due to the interactions between sodium atoms , and

the Van der Waals broadening due to the sodium-mercury interactions . In

a high pressure sodium discharge arc without mercury, the self-reversed

profile of the D- lines is symmetrical and the width of the absorption

depends on the sodium pressure. Because mercury atoms are present in the

discharge tube of an HPS lamp, they influence the profile of D- lines and

result in an asymmetrical line broadening (see Fig. 3). This asymmetrical broadening of the D- lines and the shift, AAr, of the maximum of

the red wing toward longer wavelengths is increased by increasing the

mercury partial pressure [6,13].
3.3.2.2 Determination of partial pressures from spectral

distribution

In order to estimate the existing sodium and mercury pressure

during lamp operation, several researchers have both theoretically and

experimentally studied the sodium resonance radiation from the HPS lamp.

For a quantitative explanation of this asymmetrical profile, it is

assumed that:

(1) the positive column in the arc discharge is a plasma with

cylindrical symmetry;

(2) the plasma is in a steady state and near local thermodynamic

equilibrium (LTE)

;

(3) the broadening mechanisms of the D- lines mainly include the

resonance broadening due to the mutual interactions between the

sodium atoms and the Van der Waals broadening due to the

interactions between the sodium and mercury atoms;

(4) both D-lines interact strongly.

Thus, the relationship among AAg, AAr, and the partial pressure

of sodium Pjga and mercury Py„ are [14.]:

rl AAB = 2.23X10" 5 -PNa -R^[

T

2 (p)

dp. 3X10' (1)

8. AAR

= AAB+4.78X10"°-PNa -PHg -R(AAR)M - 1 T

Z (P)

-dp

AAB+AAR

+6X10' (2)

Where AAg is the shift of the maximum of the blue wing from the center

of the self -reversed D-lines;

AAr is the shift of the maximum of the red wing from the center of

the self-reversed D-lines;

R is the radius of the arc tube

;

T(p) is the radial temperature distribution in the arc tube; and

p is the variable of radial distance from the central axis of

the arc tube

.

The function T(p) , with a strong radial gradient is roughly

parabolic. Equation (1) indicates that the location of the maxima on the

8
blue side AAg depends only on the sodium vapor pressure P^a- The shift

of AAg provides a measure of the partial pressure of sodium in a burning

lamp. From Eq. (2), the shift of the red wing maximum, AAr depends on both the sodium pressure P^a and the mercury pressure Php-- As a result,

the mercury partial pressure P^„ can be determined by the difference

between AAr and AAg. The color appearance, color rendering and luminous

efficacy of the HPS lamp are mainly determined by the sodium vapor

pressure. The optimum sodium vapor pressure for maximum efficacy is

achieved when the spacing AA between the peaks of the blue and red wings

is about 10 nm.

3.3.3 Role of mercury and xenon gases in the tube

Heat is carried from the arc to the tube wall primarily by the

sodium vapor, because the thermal conductivity of sodium vapor is higher

than that of xenon or mercury. The presence of the xenon and mercury

vapors however, do serve to raise the vapor pressure and reduce the

thermal conduction losses below that of the sodium alone, thereby

improving the luminous efficacy of the lamp. In addition, the inert

xenon gas starts the arc in the HPS lamps, and protects the electrodes

from sodium corrosion during lamp ignition. The mercury vapor in the arc tube also has another important function during the lamp life. It serves

to reduce the mobility of the electrons and thus increase the operating

voltage of the HPS lamp to a more convenient value for matching the lamp

to a ballast. On the other hand, the xenon and mercury atoms have higher

excitation potentials than sodium, and their spectral lines therefore

make a negligible contribution to the light output of the HPS lamp.

3.4 Design parameters' effects on life of lamp

Among all HID lamps, HPS lamps are the best in terms of stable

lumen output. The total luminous flux of a 400W HPS lamp is about 98% of

the initial value after operating for 17% of its lamp life (about 4,000

hrs.) and 73% at the end of its lamp life (about 24,000 hrs . )

.

The life of a HPS lamp depends primarily on the rate of rise of

the lamp voltage during the lamp's life, and is dependent on the lamp

wattage, ballast circuit, and design used by the manufacturer. According

to one author, in most practical cases, the voltage rise is determined by

a change in the sodium/mercury amalgam composition and temperature, with

the loss of sodium from the tube playing a less important role [13]. The

typical lamp starts its life operating at a voltage of about half the

value of the line voltage. Eventually, the voltage rises so high that

the power supplied by the ballast can no longer maintain the discharge,

and the lamp will extinguish.

When selecting lamps for use as a standard, the rate of change

in voltage across the lamp gives an indication of the future stability,

and therefore the suitability of the lamp for use as a standard.
3.4.1 Temperature

The blackening of the inner wall of the arc tube by sputtered

and evaporated electrode materials will raise the temperature of the

amalgam, by raising the temperature of the coolest part of the tube which

is situated near one of the electrodes. The increased temperature

increases the sodium vapor pressure and lamp v.oltage.

The light output of HPS lamps will also be reduced by blackening

around the electrodes. It should be mentioned also that, when the

sintered PCA tube operates at a wall temperature above 1150°C, an excessive alumina sublimation rate could produce dark deposits on the

vacuum outer glass bulb. If the thickness of deposits exceeds a value of

about 10 run, that can also cause significant radiant flux absorption.

3.4.2 Results of Na loss from tube

During the continuous operation of the HPS lamp, there is a slow

loss of sodium from the arc tube which cannot be completely eliminated.

The loss decreases the sodium/mercury ratio, thereby raising the mercury

partial pressure which in turn increases the lamp voltage.

The loss of sodium from the tube is caused by several factors.

Sodium can leak through the end seals of the arc tube, through the arc tube itself, or be lost by chemical combinations with other materials.

The glasses used to seal the arc tube must be carefully selected to

minimize the sodium leakage, and are usually composed of multicomponent

oxides based on a CaO-Al203 system with additional additives. The

quality of the seal is sensitive to small changes in manufacturing

techniques. The sodium can also be lost by electrolysis through the tube

wall and by chemically combining with sputtered or evaporated emitter

materials, arc tube materials, sealing glass, or impurities. Sodium loss

is accelerated if the HPS lamp is operated at excessive power [15].

4. Method of selecting stable lamps

To be a useful standard, a HPS lamp should have a dependable and

known repeatability of light output on relighting, a long useful life,

and electrical operating parameters that are within the normal values

used by the customer, such as those specified by the American National

Standards Institute (ANSI) [16]. The HPS lamps discussed in this paper

have been chosen from the products of three U.S. manufacturers.

An initial process of selection and seasoning is described that

ensured that the lamps were stable before calibrations are performed.

Care had to be taken in the choice of a method used for evaluation of

lamp changes with time. The luminous flux of the lamps of course could

be compared between companies, but lamps produced by one company would

change properties in a different way from lamps by a second company. For

example, the relative spectral radiance as a function of wavelength

changed with age on all lamps, but the pattern of the change in the

relative spectrum differed from one manufacturer to another. Therefore,

10 i
some of the tests done on the lamps were valid only for comparison

between lamps made by one manufacturer.

In order to select HPS lamps that will have a relighting

repeatability of within +1% of the mean value, close attention had to be

paid to the changes in lamp output during seasoning. The suggested

seasoning cycle consists of 1 hour off for every 11 hours burning time

for a period of about 600 hours [17]. All lamps have been measured at a rated power of 400W. The power for seasoning the HPS lamp was supplied

by an ELGAR Model 3001 AC voltage stabilizer. The recommendations of the

CIE were followed, making measurements at intervals of about 100 hours to

determine the changes in radiometric, photometric and electrical

operating parameters as a function of time during the seasoning days

[18].

The following evaluations of lamp performance were made:

(1) When operating inside an integrating sphere at 400 watts, the

electrical parameters (lamp voltage V and lamp current I) were

recorded. Relative values of the spectral radiance of the sphere

window were measured, from which the integrated radiance Le , luminance L^, luminous flux $v , chromaticity coordinates (x,y)

and correlated color temperature Tc were calculated;

(2) Determination of AAr and AAg from the spectral power distribution

curve ; and

(3) Measurement of the relative intensity of one of the mercury

spectral lines as a function of time during lamp ignition. After

the arc in the HPS lamp has been stabilized, the mercury lines can no longer be detected. To determine clearly the transition

time from mercury vapor discharge to sodium vapor discharge, the

blue mercury line at 435.8 ran was chosen because the sodium

continuum spectrum is weak at this wavelength.

All lamps were seasoned for 100 hours before luminous flux

measurements were made. After this initial 100 hours of seasoning, flux

measurements were made at approximately 100 hour intervals between 100

and 600 hours of operating time. From measurements made during this 500

hour period, it was found that lamps from certain manufacturers could be

predicted to be stable if they met the following criteria: the light

output varied by less than 2% per 100 hours of operation during the 100

to 600 hour burning period, the relative spectral power distribution

changed negligibly, and the time for transition from mercury discharge to

sodium discharge stayed constant. Meeting these criteria, these lamps

could be expected to have a luminous flux stable to within 1% for an additional 500 hours. Such a lamp is suitable for use as a working

standard. Typical data is given in Table II which will be discussed

later. If the light output of an HPS lamp varies more than 2% per 100

hours of operation, irregular results could generally be expected, and

this lamp should be rejected.

11
HPS lamps which had passed the stability screening test were turned

off and on 10 times on different days to verify the repeatability of

light output to within +1% of the average value.

5 . Description of the measurements

5 . 1 General

The nominal luminous fluxes of the high pressure sodium lamps were determined using the equipment shown schematically in Figure 4. The

lamps were placed inside a 2 meter diameter integrating sphere, and

readings of the luminous flux exiting the sphere were obtained with a commercial spectroradiometer with associated computer hardware and

software. Similar readings were taken for incandescent lamps with known

luminous fluxes, and then the luminous fluxes of the high pressure sodium

lamps were obtained from the expression:

$v,x = $v,s sv,x/sv,s (3)

where $v x and $v s are the luminous fluxes of the test and standard

lamps, and Sv x and Sv s are the photometric readings provided by the

spectroradiometer and computer. The chart recorder was used for

following changes in the intensity of spectral lines as a function of

time. For more details on spectroradiometric measurements of luminous

flux see references [19] and [20].

Spectroradiometer

< > Computer

Strip chart

Recorder

< > Printer

X-Y

Plotter

Fig 4. Schematic diagram of the experimental equipment.

12
5 . 2 Lamp operation

5.2.1 HPS lamps

The electrical circuit for electrical and photometric measurement

of HPS lamps used is shown in Fig. 5. The AC power for HPS lamps was supplied by an ELGAR 3006B, 60Hz sine wave, line conditioner with

harmonic distortion less than 0.2% and with regulation of ±0.025%. The

voltage, current and wattage were measured by a YEW Type 2503 digital AC

power meter with true rms response. One phase of the power supply and

one side of the ammeter were grounded together in order to prevent the

possibility of electrical shock.

The power to the HPS lamps passed through a reference ballast of

the variable- impedance type. It consisted of an adjustable reactor and a variable resistor connected in series. The required values of impedance,

power factor, and the corresponding current of the reference ballast were

as specified by ANSI [21]. For a 400W HPS lamp, these values were:

Impedance: 38.6 ohm

Power factor: 0.075 ±0.005

Reference current: 4.6 amperes

Every time a change was made in the adjustment of the reference

ballast, it was necessary to measure and to possibly reset the lamp

voltage, current, and power factor.

Line

Conditioner.V

110V

AC Input

T

.v

Fine

20

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Coarse

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/ V.

! I

A

Watt-Amp-Volt

Meter

/

Hps

Lamp

Fig 5. Electric circuit used for operation, control, and measurement of

electrical parameters of HPS lamp.

Switches V and A were provided so that the voltmeter or ammeter

impedance were removed from the circuit when not being used. The

following electrical measurements were recorded: the voltage supplied to

the lamp and ballast, the lamp current and the voltage across the lamp

13
with the lamp wattage held at 400W by adjusting the variable AC supply.

Electrical characteristics of each HPS lamp were measured immediately

after photometric measurements had been made.

The HPS lamps were operated for 40-60 minutes before making optical

measurements so that the electrical characteristics and the light output

would be stable. The HPS lamps were measured after the ambient

temperature in the integrating sphere had been stabilized. (To shorten

the testing period, the HPS lamps could be allowed to warm-up outside the

sphere on an ordinary ballast, and then transferred to a reference

ballast without being extinguished and moved into the sphere for

measurement .

)

5.2.2 Incandescent standards

A group of five 500-watt clear gas-filled incandescent lamps served

as NBS working standards of total luminous flux and were used to obtain

flux values for the HPS lamps. These incandescent lamps were run on DC

power supplies, with a stability of 0.01%. The electrical parameters of

the lamps were measured with a digital multimeter to an accuracy of

0.02%. The lamps were allowed to stabilize for at least 10 minutes

before measurements were made.

5 . 3 Integrating sphere properties

The lamps were mounted vertically with the base up in the center of an integrating sphere. The inside of the integrating sphere was coated

with pure barium sulfate powder, without binder to minimize absorption in

the blue. A 7.6 cm diameter observation opening with a white diffusing

plastic window was located on the sphere wall, from which the spectral

radiance as a function of wavelength was measured using a spectroradiometer . A pear shaped baffle coated with commercial sphere

paint shielded the sphere window from direct illumination by a lamp. The

baffle screen was approximately 20.5 cm by 27 cm. For this work, the

distance between the lamp and the baffle was about 1/3 of the radius of

the sphere. The radiant flux of the lamp was diffusely reflected on the

inner wall of the sphere and thus was depolarized. A blue filter was inserted between the window and the spectroradiometer in order to correct

for the non uniform spectral throughput of the sphere photometer. The

filter altered the relative spectral distribution of the flux incident on

the spectroradiometer to approximate the distribution produced by the

lamp alone

.

Because the HPS lamp differs from the 500W incandescent standard

lamp in self -absorption of luminous flux within the integrating sphere,

the ratio of the self -absorption of the HPS lamp to that of the standard

lamp was measured using a stable auxiliary incandescent lamp mounted near

the inner wall of the integrating sphere. The auxiliary lamp had the same relative spectral power distribution as the standard lamp. No light

from the auxiliary lamp could directly illuminate the observation window

of the sphere, or the lamp in the test position. The unlighted standard

lamp or the HPS lamp was located in turn at the center of the sphere.

14
The ratio of luminances of the observation window with the standard lamp

in position to that with the HPS lamp in position, is the correction

factor for self-absorption. Experimental results show this ratio, a, for

three manufacturers' HPS lamps as follows:

Manufacturer a A 1.002

B 1.003

C 1.003

The corrected luminous flux of a HPS lamp is obtained by multiplying the

measured flux by the ratio a.

The reflectance of the sphere used for the measurements has a slight

spatial nonuniformity. Since the light leaving a HPS and incandescent

lamp have different geometrical distribution patterns, it is possible

that the measured signal is in error due to the combination of

nonuniformities . In order to estimate the error due to this effect,

sample lamps were measured in 4 positions differing by 45° in rotation

about the vertical axis through the lamp. For each angle, the relative

luminance on the observation window was measured by the spectroradiometer. The relative luminance differences of the standard lamp and

the HPS lamp were less than 0.1% and much less than 0.1% respectively.

No correction was made for this error. From previous experience, if the

rotation interval were <45°, the estimated uncertainty due to a different

spatial distribution would be less than 0.2%.

5 .4 Spectroradiometer properties and measurement techniques

The spectral fluxes exiting from the sphere were measured using a Pritchard 1980B scanning spectroradiometer. The photomultiplier cathode

of the spectroradiometer was illuminated for 40 minutes by power levels

expected during later measurements. The output of the spectroradiometer

varied as a function of time. A typical curve is illustrated in Figure

6. After the initial 40 minutes of exposure, the measurements were

stable for an additional two and a half hours.

5.4.1 Linearity

The deviation from linear response of the detecting system depended

chiefly on the level of the anode current of the photomultiplier in the

spectroradiometer. The non-linearity was checked using the doubleaperture method [22]. For our experimental conditions, the non-linearity

_ o of the reading for the spectroradiometer ranges of 10"^ and

10 -> WSr~-L m~ znm x was 0.5% and 0.3% respectively. For the reading ranges

from 10"^" to 10" 'WSr'-'-m'^nm"-'- , the non-linearity was negligible. No

correction was applied to the data. If corrections for non linearity had

been applied to the measured signals, the resulting corrected value of

the luminous flux would have been about 0.2% higher than the flux based

on uncorrected data.

15
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Fig 6. Signal from spectroradiometer as a function of time of exposure

to a stable level of optical radiation.

16
5.4.2 Measuring aperture

The measuring field aperture of the spectroradiometer was chosen to

be 20', 1°, or 3° for our experiments. Because the observation window in

the sphere wall was a white diffusing plastic, and because it was illuminated by multiple diffuse reflections from the inner wall of the

sphere, uniform luminance exited from the observation window.

Experiments indicated that the different angular measuring fields did not

affect the final value for total luminous flux. Since the total luminous

flux of a 400W HPS lamp was higher than that of the 500W incandescent

lamp, different field apertures were chosen for these two lamp types to

match signal levels, and thereby avoid any possible non- linear response

of the detecting system.

5.4.3 Wavelength range and interval

The spectral range covered 370 run to 730 run, using 1 nm, 5 nm or 10

run bandpasses, and a wavelength sampling interval of 5 nm, the maximum

suggested by CIE. Values for V(A) outside the measured region are <0.05%

of the peak value, and therefore do not contribute significantly to the

flux.

5.4.4 Wavelength scale accuracy

The spectroradiometer wavelength scale was checked by using the

spectral lines of a low pressure mercury lamp in the visible range. The

indicated readings of the digital wavelength scale were shifted toward

longer wavelengths by 1 nm from the true value. Since an accurate

measurement of the flux of these lamps will be later determined by

goniometric measurements, a correction from the wavelength error was not

made. It was estimated however, that such a correction would increase

the values of the luminous flux by about 0.3%.

5.4.5 Spectral bandwidth

Spectral bandwidths of 10 nm, 5 nm or 1 nm were used during

calibration of the HPS lamp. If the same bandwidth were chosen for

measurements of both the HPS lamps and the standard lamp, the luminous

flux assigned to a HPS lamp differed by only 0.1% to 0.2%, depending on bandwidth used. Thus, it is evident that the spectral power distribution

of a HPS lamp can be measured by sampling as if it were a continuum

spectrum. In order to reduce the measurement time to avoid possible

long-term drift of the detecting system and to follow CIE suggestions,

the band-width of 5 nm was chosen for measuring the luminous flux and the

chromaticities of the lamps.

5.4.6 Radiometer AC response

The 500W working standards of total luminous flux were run on a DC

power supply, but the HPS lamps were powered by an AC source. The

luminous flux of the HPS lamp was therefore modulated at 120 hertz. The

spectroradiometer was checked to see whether it responded to the varying

17
signal correctly.

The test showing insensitivity to an AC modulated signal used a chopped source, a rotating disk with two 90° apertures , inserted between

a stable lamp and the spectroradiometer . The chopper was set at a rotational speed of 60 CPS , producing a chopping frequency of 120 Hz.

The ratio of the readings with and without the chopper gave a measure of

the transmittance of the chopper. In our experiment, the calculated

transmittance of the sector disc was 0.5, based on measurements of the

angular openings in the disc. For spectroradiometer reading ranges of

9 -7 -1-9 -1 10~ z to 10 ' WSr x m ^nm *

, the relative difference between the calculated

and measured transmittances was less than 0.1%. Therefore, the detecting

system obeyed Talbot's Law.

5 . 5 Measurements made and analysis of the data

5.5.1 General description of spectroradiometer data acquisition

Under the measurement conditions described, the instrument

photometric readings Sv xor Sv s appearing in Eq. (3) do not correspond

precisely to the luminous fluxes of the test and standard lamps:

*v = Km $A V(A) dA (*)

where Km

= maximum luminous efficacy (lm/W) , $A = spectral radiant flux,

V(A) = values of spectral luminous efficiency for photopic vision.

Rather, the readings are given by:

Sv - Km $A V(A) f(A) R(A) dA (5)

where f(A) is the spectral throughput of the integrating sphere and R(A)

is the spectral responsivity of the spectroradiometer detection system.

Because the accuracy of calibration factors used by the data

processing routines of the spectroradiometer were unknown, the following

assumptions were made to estimate the magnitude of the systematic error

that can result from the difference between the integrals of Eqs . (4) and

(5):

(1) The spectral distribution of a HPS lamp in a manufacturer's

catalog represented the relative values of the HPS lamps'

spectral distribution, $\ x ; (2) The spectral distribution of CIE Source "A" represented the

relative values of the standard lamps' spectral

distribution, $A s ; (3) The throughput of the integrating sphere was estimated

experimentally. The relative spectral irradiance of a lamp in one direction was measured on an optical bench using the

Pritchard Spectroradiometer. The lamp was then operated in the

18 i
sphere used for calibrations. The spectral irradiance leaving

the sphere was then measured with the same spectroradiometer

.

The ratios of the values of spectral irradiance were used as the

values for f (A) ; and

(4) Values for instrument response R(A) were approximated by the

relative response of a S-20 type photomultiplier

.

The error in the measured luminous flux due to nonuniform sphere

throughput was calculated by comparing the ratio of measured signals

affected by the throughput of the sphere

:

2 $A x V(A) f(A) dA

Rl = , (6)

2 $A>S V(A) f(A) dA

with the ratio of "true" signals that would be produced by a system with

uniform throughput;

2 $A x V(A)dA

RTrue = • (7)

2 $As V(A)dA

The ratios calculated by these two different methods varied by

+2.1%.

Similarly, the error in the measured luminous flux due to varying

instrument response was calculated by comparing the ratio of measured

signals that were affected only by the instrument response:

2 $A x V(A) R(A) dA

R2 = (8)

2 $As V(A) R(A) dA

with the ratio of "true" signals of Eq. (7). The ratios calculated by

these methods differed by -3.7%.

Since the errors calculated by the above ratios are of opposite

sign, the errors would cancel somewhat when combined in a ratio that is

based on Eq. (5) :

2 $A xV(A) f(A) R(A) dA

R3 =

' (9) s $A,s V ( A ) f ( A ) R ( A > dA

When Eq. (9) is compared to the "true" value of Eq. (7) a net error of

19
-1.1% results. However since the assumptions used may not have applied,

the errors calculated individually from the ratios ^-l/^-True an<^ R2/Rxrue will be combined together in quadrature when determining the

overall uncertainty of the measurements.

5.5.2 Summary of uncertainties evaluated

In addition to the errors associated with the HPS lamps and the

equipment used in the measurements, there are error contributions due to

the transfer from standards to test lamps, and to the standards

themselves. The uncertainty of the working standards is taken from

values in ref. [23]. Included are the total uncertainty of the working

standards relative to the NBS primary reference group (1.1%), plus the

random variation in the transfer from the working standards to the test

lamps due only to the working standards (0.3%). (Since the HPS random

variation was determined separately and is included in the 1.0% stability

uncertainty, the random error of the standard is calculated as the square

root of half of the square of the combined value reported in ref. [23].)

The possible sources of error and the estimated uncertainties in

the spectroradiometric measurement of the luminous flux of HPS lamps are:

Item Error Source Uncertainty

(%)

Spectroradiometer Calibration factor 3.7

Sphere throughput 2 .

1

Wavelength error .

3

Non-linearity (residual error) 0.2

Stability 0.2

HPS Lamp Stability 1.0

Self-absorption (residual error) 0.1

Spatial distribution 0.2

Digital wattmeter . 3 Working Standards Uncertainty relative to NBS

standards 1 .

1

Random variation of transfer 0.3

Total Uncertainty ±4.6%

(calculated from the square-root of the sum

of all uncertainties)

.

6 . Results of the measurements

6 . 1 Sphere measurements of total luminous flux

The measurements of lamp properties reported in this paper relied on measurements of luminous flux. For the determination of lamp stability

and relighting repeatability, the flux did not have to be measured

accurately. It was satisfactory to look at differences in uncorrected

flux, as shown in Table II for stability over time, and similarly in

Table V for repeatability. Corrections discussed in section 5 therefore

20
were not applied to the data in tables II through V. The tables are printed after the figures at the end of the text.

Luminous flux values for selected stable lamps appear in Table VI.

The fluxes are based on the average of the relighting data in Table V,

corrected only for lamp absorption in the sphere as discussed previously.

The values of luminous flux are subject to the uncertainty discussed in

the previous section.

6 .

2

Ambient temperature effects on luminous flux

The ambient temperature inside the integrating sphere during

measurements was maintained at 35 °C + 5°C. In practice, it is difficult

to maintain the ambient temperature at 25° + 5°C as suggested by ref.

[24] . The temperatures were measured using a copper-constantan thermocouple with a 0.1 °C resolution digital- thermometer , positioned to the

side at about the same height as the lamp, and shielded from the lamp.

For a 400W HPS lamp, the temperatures at different positions inside the

sphere are shown as follows:

d(cm) 8.0 16.5 26.0 36.5 50.5

t (°C) 36.9 35.4 36.4 37.2 37.2

where d is the distance between the thermocouple and the observation

window, and t is the ambient temperature, which will vary with different

lamps. The IES suggested position is at a distance between 20 cm to 1/3

of the sphere diameter from the inner wall [24].

As shown in Table I, the photometric characteristics of the HPS lamp

depend very little on the ambient temperature after the sphere is closed

for 5 minutes, and after 30 minutes the parameters are approximately

constant.

6 .

3

Lamp wattage influence on luminous flux

The HPS lamp measurements during the stable operating period were made at different wattages to investigate the influence of lamp power on total luminous fluxes, radiant fluxes and chromaticities . The wattages

were changed from 390W to 410W, Table III and Figs. 7 and 8 (on the next

page) show that the luminous fluxes of the HPS lamp were proportional to

the wattages between 396 and 408W. If the lamp wattage changed 1W at

400W, the luminous flux changed less than 0.4%, and the chromaticities

remained the same. It was easy to control the wattage to within + 0.25%

of the rated 400W.

21
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Fig 7 . Luminous flux of a HPS lamp from manufacturer A as a function of

power through the lamp, relative radiance versus watts. —

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Fig 8 . Luminous flux of a HPS lamp from manufacturer B as a function of

power through the lamp, relative radiance versus watts.

22
6.4 Repeatability of relighting

Changes in the amount of light produced by a lamp when relighted is

of prime interest for lamps to be used as standards. Therefore a group of

HPS lamps was tested for their repeatability of relighting.

After seasoning for about 500 hours , a group of HPS lamps was measured at least 10 times in two months, with no additional aging,

operating the lamps only long enough to reach stability and to make

readings. Each lamp was operated for a total of approximately 7 burning

hours while conducting this test. The sphere signal from the HPS lamps was compared to the signal from the NBS working standards. The HPS lamps were found to repeat to within ±1.0%, satisfactory for use as a standard.

The standard deviation of the repeated measurements of luminous flux of

individual lamps ranged from 0.2% to 0.5%. The changes in radiant flux,

lamp voltage, lamp current, correlated color temperature, and their

relative standard deviations are shown in Table V.

6 .

5

Stability of lamps as a function of lamp burning time

6.5.1 Photometric

The data of Table II shows experimental results from measurements

of a number of commercial 400W HPS lamps over a period of 1200 hours of

operation. Among the lamps included in the table are lamps from 2 manufacturers, some found to be stable and others unstable. Measurements

before approximately 500 hours, shown above the 1st dotted line, are burning times during which the lamps are being seasoned, and according to

manufacturers' data would not be expected to be stable. After the 1st

dotted line, and for an additional period of 400 to 600 hours of

operation (depending on manufacturer) , some lamps exhibited a "stable"

period during which the relative luminous fluxes changed by less than

+1%. During that time, there was negligible visual increase of the end

blackening of the arc tube. The second column under each lamp starts a new time for lamps considered to be in their stable period. After the

second dotted line, the lamps had drifted in luminous flux by more than

1%, and were considered to have left the stable period of their life.

These experiments were repeated with four more groups of lamps with

similar results. A third manufacturer's lamps showed irregular results.

6.5.2 Spectral power distribution

The blue peak of the spectral power distribution depends only on sodium partial vapor pressure, while the red peak depends on both sodium

and mercury vapor pressures. If the sodium/mercury ratio or the

temperature of the amalgam changes during operation, the spacing of the

peaks of the spectral distribution curve, AAg and/or AAr will shift

indicating that the light output of the HPS lamp has been changed.

Experimental results are shown in Fig. 9 to 12. For two

manufacturers' lamps, each lamp had the same profile during the time from

23
500 hours to about 1000 hours. After about 1000 hours, the blue and red

peak profiles changed slightly. The widths of the blue peak and the red

peak of one manufacturer's lamps showed some contraction (Fig. 9 and 10)

and the others showed small expansion (Fig. 11 and 12). Accurate

measurements of the wavelength shifts of AAg and AAr have been difficult

because the burning time covered in our experiments was much shorter than

the average life of the HPS lamp. But it was evident that the ratio of

sodium/mercury amalgam and/or the temperature of the coolest part in the arc tube had changed slightly, and affected the luminous output of the

HPS lamps. The third manufacturer's lamps showed irregular results.

These results generally corresponded to the previous results shown in

Table II.

6.5.3 Shift of discharge from mercury discharge to sodium

discharge

During the HPS lamp ignition, the mercury vapor builds up and

discharges in the arc tube. Then sodium vapor increasingly contributes

to the light output. If the ratio of the sodium/mercury amalgam and/or

the temperature of the coolest part changed slightly, the time to shift

from mercury discharge to sodium discharge will change.

The signal at the blue mercury line, 435. 8nm, was measured as a function of the ignition time when starting a HPS lamp. Typical curves

are shown in Fig. 13 and 14. The signal due to the blue line increased

to a maximum value in 50 to 80 seconds , then decreased to a minimum after

80 seconds to 130 seconds. The signal then rose again from the minimum,

but this rise was due to the sodium discharge and not the mercury line.

Finally, the signal approached a constant. The times varied with

different lamps and at different periods in lamp life.

The experimental results for two manufacturers' lamps are tabulated

in Table IV. The time the curve takes to reach a minimum is defined as the transition time from mercury discharge to sodium discharge. As phe

burning time is increased to 1000 hours or more, the transition time of

one manufacturer's lamps increased slightly, while a second's lamps

decreased. The third manufacturer's lamps show irregular results. These

results also generally correspond to the results in Table II.

7 . Summary

Fifty high pressure sodium lamps from 3 manufacturers have been

extensively examined. Various properties of the lamps have been observed

during 1200 hours of operation. From these measurements, those

properties that are useful for predicting if a lamp will be stable, based

on measurements made during lamp seasoning, have been determined. Twelve

lamps have been selected that are predicted to have an estimated

repeatability of light output within ±1.0%, during an estimated useful

life time of about 450 hours. These lamps are suitable for further

spectral calibration. Their luminous flux has been measured. Further

calibration will be done using a spectral goniometer.

24 \
Acknowledgment

The authors would like to express their appreciation to

Dr. K.D. Mielenz for his continuing guidance and encouragement

and to Mr. D.A. McSparron and Dr. J.J. Hsia for enlightening discussions

and help on this subject.

25
s BEL ^ BZL*

XL ^

BBL $

5f i

4

X ^-^ in X V„ to 1-4 o> i-l f- *~^ 1

1 X -3" Vi, VC o

00 o o -3- o .-I "^ "

*-'

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• • • o o o z 2: s

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ID in •flea m

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cad

Fig 9. Spectral power distribution of a HPS lamp at various burning

times. Curve 1 was the distribution measured at 486 hours of

operation, 2 at 906 hours, and 3 at 1165 hours.

26
01 03 t^ CD ID <t m (M s S S (S! S Q Q Q

Fig 10. Spectral power distribution of a HPS lamp at various burning

times. Curve 1 was the distribution measured at 586 hours of

operation, curve 2 at 1095 hours.

27
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X-3- o

o *-^ ^^

rH X X

1 Vi- co

rH rH rCT> r-l rH m i—

1

r-l w "

"

r-l r-l rH

• • • o o o z z z

a a a

F E E

al 03 CO h4

1 -1

1

t-l

1

l r-l

l C\J K1

a 0) CDQ

IDQr\j Q

Fig 11. Spectral power distribution of a HPS lamp at various burning

times. Curve 1 was the distribution measured at 591 hours of

operation, 2 at 1116 hours, and 3 at 1178 hours.

28
O) GO t^- IO ID T m (M Q S3 S Q Q s Q s

Fig 12. Spectral power distribution of a HPS lamp at various burning

times. Curve 1 was the distribution measured at 748 hours of

operation, curve 2 at 1116 hours.

29
300

250

200

150

100

50

Time

(Seconds)

Minimum

(86")

Scale

Change 4-

Maximum

(55")

Start Signal

Fig 13. Relative spectral radiance of a HPS lamp measured at the

435. 8nm mercury line as a function of time from lamp ignition.

Relative radiance is plotted, with the signal amplification

reduced between 22 and 48 seconds, against time in seconds. The

sodium discharge matches the mercury discharge after 86 seconds

of operation.

30
300

250

200

150

100

50

Time

(Seconds)

Minimum

(115")

Scale

Change ]_ v^

Maximum

(74")

Start Signal

Fig 14, Relative spectral radiance of a HPS lamp measured at the

435 . 8nm mercury line as a function of time from lamp ignition.

Relative radiance is plotted, with the signal amplification

reduced at 50 seconds, against time in seconds. The sodium

discharge has risen to match the mercury discharge, which is

declining from its peak, after 115 seconds of operation.

31
bOa

•HWo

V

4J MH

cO

T3O

•i-4

!-l 0)P.

S-l do

rC

CDC

O

S-l >

oc

o

•Hu

cd

s-i <ua-o

a)M

(U S

A3 O

P. -o r-^

co c CD u

•H 5-1 s—

a) 3 3

X) 4-> (X

•H c cO s

CO o 5-1 cO C •H CD r-l •H 4J cx

CO E CO

CD > <U PL| H U 4-> 33 3 CD U CO M

CO -Q O

S-i O H

CD o a 4-> C o

a c o

CD CD T3

4-1 S-l <d CD

1-1 o 4-> 4-) 3 C CO c o cO rH

0) c 0) y^N •H p- •H »-l CQ rO S s J-l

1—

E cfl 3 o

cfl —

1

r-l o P-E

cO O > o H

4-> M rJ H

CO

33

3

w o a T) -0 E CD c

cO CO •r-l r-l O

r-l

r* co /"N CO o c CD <

P-i o 4-) -W

33 CO r-l CO •H 4J C a

(4-1 <d CO •H E

O r-l CD > T3 cO

CD S-l S-l S-i rH

(0 rC (D CD O

o P- 43 W O CO

•H co a. X O fXl

4-> CO CD o 33

co bO bO >-, •H (3 S-l cO c 4-» n •r-l CD 4-> o •H

CD 4-> 4-> rH O

4-) cO C4-I O CD •H

S-i CO > 4-> cd bO c CO U CD CD Ou cd S

cO 4-> E e •H O

X C •H cO TJ S-i u •H 4-> •—

1

CO

>-l rCo

H

1

CD

r*>

aj 4J > rJ X h

A

aj H

CM i-l CM VO VO OO VO CM O

• <t U~l O CM CM ON o<fmvtcMr>»m<tr>.

vo co o o

rH <f CM 00 O O CM

CM rH oo r^ -j- in vo cm o

• <j- m CT> CM CM 00 OfOin<tNvOKl>jN

CO CO o o

H <f CM 00 O O CM

On On m O CM CM O

• CO VO r-l CM CM O

moNin<tcMr^in«3- oo

CM O O

rH -tf CM 00 O O CM

co r-~ CM CM 00 4 <f >* <t

• • CM C~. rH CM r-l r^ o<tcMincMOm<fM

vo co O O

H<f NO\ OON

CO VO

co -J- O co CO -J- <t

• cm r^ o cm rH r^ o<tcMincMOin<fcM

co co O O

rH -H/ CM ON O O CM

co r- OV 4 r-l 0O M <t st

• CM VO On CM rH 00 inocMtncMONin<tcM

CO O O

rH >^ CM 00 O O CM

On CM

I-- <) CM CM rH rH O

• 1^ 4 ON CM CM CM o-*r~cocoom<i-oo

r- co o O H^CSONOON

00 CO

in m vo in on rH o

VO -^ ON CM CM CO O-cfr^cocoom-^oo

CO CO O O

rH <t CM On O O CM

oo co

rH in O VO CM rH O

• r-» <t rH CM CM CO mrHr-cocorHin-ct-oo

CO o o

rH -J" CM On O O CM

CM CM E E

• \

J-4 T)

CO o ^ DECO C r-N O O

•H U ^-^H H

E o P> < X X ^

O CD > O

4J4->>MrJrJ X >*,H

32
Table II. Luminous flux o f HPS lamps as a functio l of operating life time.

Lamp No. 1 Lamp No. 2 Lamp No. 3

(hr) (hr)

*(lm)

%100 hr % (hr)

l

2 (hr)

*(lm)

^7/ 100 hr

9 %

(hr)

*2 (hr)

*(lm) %100 hr

9 %

_ _ _ 162 50690 162 52210 162 50160

262 50520 -0.34% 262 51960 -0.48% 262 49100 -2.11%

377 50020 -0.86% 377 51510 -0.76% 377 49520 +0.75%

477 50210 +0.38% 477 52190 +1.32% 477

591 680

48150

48360

47650

-2.77%

+0.44%

591 49740 -0.94% 591 51230 -1.84% -1.47%

680 89 49350 -0.78% 680 89 51190 -0.08% 748 48150 -0.43%

748 157 49490 -0.50% 748 157 50810 -0.82% 801 47590 -1.59%

801 210 49520 -0.44% 801 210 51300 -0.14% stop

851 260 49220 -1.00% 851 260 51240 +0.02%

898 307 49380 -0.72% 898 307 51060 -0.33%

951 360 49340 -0.80% 951 360 51210 -0.04%

1004 413 49270 -0.95% 1004 1054413

463

50900

50790

-0.64%

-0.86%

1054

1116 49230

49160

-1.02%

-1.16% 1116 50510 -1.41%

1178 49070 -1.34% 1178 50450 -1.52%

Lamp No. 4 Lamp No. 5 Remarks

(hr) (hr)

*(lm) %100 hr % (hr)

t

2 (hr)

*(lm)

%100 hr %

t, : operating time

t : operating time

during stable period

*: luminous flux

(a*/$)/100: relative flux difference per 100 burning hours

%: relative flux

difference from the beginning of the stable period

172 270

378

46580

46440

46950

-0.31%

+1.02%

172 270

378

46750

46120

46220

-1.38%

+0.20%

486

586 694

793

906 1004 1095

1165

100 208

307 420

518

609

679

46590

46560

46560

46510

46530

46370

46370

46180

+0.71%

-0.06%

-0.06%

-0.17%

-0.13%

-0.47%

-0.47%

-0.88%

486

586 694

793 906

1004 1095

100 208

307 420

518

609

45730

45770

45340

45720

45760

45660

45710

-0.98%

+0.09%

-0.85%

-0.02%

+0.07%

-0.15%

-0.04%

1165 45250 -1.05%

33
COoz

Q.E

<0 _]

X

i X X X a* i X i coitinoo i in

t OlDl/lN 1 »

1 o o O O O 1 ri

i i i i i i i

o

1—

1

e-l «

<l

-1.04% +0.22% -0.61%

«• r- OOOO IOOOOOOOOOO IO in cm in io luomcncomcninoocMCM i in

i iO Oi O in ii— mco«3-r--mincMcocM i 10

co r-~ oo r-~ i r^ r-~ r~ r- r-~ t^ i— i— r~. r> i ic

*3- >3- "3- «d- i^r^->a-^J-'d-^r^i-'^-'a-"=d- i **•

4-> x:

i o c cMvinw i

1 CU i—l CM CO «d- 1

i E i hL

-4-> -C OO'tl/lN lOOOOOOCnr-^LOCM i «=r 0<- 10 ro i«^-^-<*'d-'d->*vor~.i~-oo i m •—i w m in Mnininininmio^MW io

1

o

Q.e

_1

X

i X x X X i X 1 l»)<t>tCl 1 io

1 CO O CO 00 1 CO

1 o o o O O 1 H

i + i i i i i C

O

ol—

1

<l

-0.91% -1.18% +0.78%

1"

«i . oooo ioooooooooo io

en en co en i ai o> co r^. io o> m i— cmco icm

i rn m ffnf ioococoocm.—ico.—<oi-- i m

o en co en icocncncncncncncncnco ico

in^*-«*«3- i^-«a-^-^-<*«^-«d-«a-'5i-<a- i"^-

CMC

4-> .C

i o zcoiD'tH i n

1 CO CM CO CO in 1 CM

i aj —i cm co ^- i m

1 E 1

+-> -CI o o cm m •—i loooooocom^--—i ico oco<* en toooooocMcocoin icmi—< cm co «d- i inmininininiDNajoi io

T3O CU i— O -C

l_ 4-> CD i—

1

ai Q. F x:

(1) CD t_ o +-> tr E CD X X 0) 1/1 X t_ "O

•r- i— i— Z3 zz a. l_ 3 li- >4- O -4-> +-> .O r— r— 3 ^~ O !-

<o 14- i+- a> O <4- CU C- o> C71+J o £ o en ai c C CO </) 01 c cu c C Q.

CO •r— 'r— Z3 > CU o> > CU • r—

_*: •4-> +-> en o •r- t_ c • r- l_ C 0)

C_ CO rt3 c c 4-> ai 1— •4-> CU C i

<a l_ i- •- •1— IO <4- c (O n- •1- X) E CU CO £- E — 14- t_ 1— 4- CD t5

0) CL O. ZZ 3 QJ •- 3 ai •1— CU -l-> Oi o o -a 1— t- "O £l t_ T3 JO LO

,_, CM «. O x -4-> 4-> O1—1

- --&~ <

o

o

E

<o

X

in ao cm

in r^ en o •—I <—1 CM

i i i

szoo.—

I

<l

-0.84% -2.17% +0.81%

1"

6- .— ooooooo o.

ro in cm oo r-- in >* o

i m.—imoo<-<om+j

i— r^ in in /) in ^ to

*i- <a- «d- «* «^- *!- >^-

CMt-

•4-> SZ

.-it4-> x: OOMCOlOlDM"t i-l CM 00 CO CO O i-l

•—I cm co ^- in r~- oo

-a

cu

oo

XXX O *d- co

co in i—

i

X

O i—i o i—

i

i i i t_ £1 X X o in i

MO o -T> .—

i

1—i

. ~~~. CM O CM o •e-l •& 1 1

o.

<l OOOOOOO E * "d_ minmr--coco o. m E i JiroriMio *cn o

_i «• i

MDion<j>jnp —

«3-*t"3-^t->3-<3-^- io

, , CMC4-> .C"~

^ ocmocoioio-^-co

—il_ r-— r— i— oo co en en

4-> SZ i—i cm co *$ in in i

•"

eno

z.

a.E

10 _l

X

-0.22% -1.55% +0.24%

szoo1—

1

<l

-2.13% +0.69% -2.29%

"e

6- i— ooooooo CL. en o •—i iDicinio o

i <t eo eo i— ioOi—'•!-> MDionmin^i co «r <^- «s- >3- «r «* >^-

CMt4-" -C

+-> SZ ooooximincMi*

•-I CM CO CO CO O i—

l

•—i cm co ^- m r-^ oo

34
Table III. Photometric and electrical properties of HPS lamps from two

manufacturers as a function of power supplied to lamp.

v

T.

Lamp Wattage

Lamp Voltage

Lamp Current

Percent of Integrated Radiant flux at 400 W Percent of Luminous flux at 400 W Chromaticity coordinates

Correlated color temperature

Lamp A

W(W) V(V) 1(A) L e

(%) L

v (%) X y T

C

(K)

390 105.7 4.323 97.27 97.91 0.5242 0.4185 2051

392 106.2 4.329 97.90 98.35 0.5242 0.4185 2051

394 106.5 4.339 98.28 98.67 0.5241 0.4184 2052

396 106.8 4.348 98.61 98.94 0.5240 0.4185 2053

398 107.1 4.359 99.29 99.50 0.5240 0.4184 2053

400 107.4 4.368 100.0 100.0 0.5242 0.4183 2050

402 107.7 4.374 100.6 100.5 0.5241 0.4183 2051

404 108.1 4.383 101.5 101.2 0.5242 0.4182 2050

406 108.4 4.390 101.8 101.4 0.5241 0.4182 2051

408 108.8 4.397 102.5 102.0 0.5240 0.4182 2052

410 109.1 4.404 103.3 102.6 0.5241 0.4178 2048

Lamp B

W(W) V(V) 1(A) L e

(%) L

V U) X y T

C (K)

390 101.6 4.486 96.60 97.69 0.5236 0.4167 2045

392 102.3 4.481 97.49 98.27 0.5240 0.4162 2039

394 102.8 4.480 98.10 98.63 0.5241 0.4160 2037

396 103.4 4.480 98.90 99.19 0.5240 0.4161 2038

398 103.9 4.481 99.43 99.63 0.5237 0.4162 2040

400 104.4 4.482 100.0 100.0 0.5236 0.4162 2041

402 105.0 4.484 100.5 100.5 0.5232 0.4164 2046

404 105.5 4.485 101.2 100.9 0.5233 0.4162 2044

406 106.0 4.484 101.7 101.2 0.5232 0.4162 2045

408 106.5 4.486 102.4 101.7 0.5231 0.4162 2046

410 107.0 4.486 102.8 102.0 0.5230 0.4164 2049

35
Table IV. "Transition time" for the radiation from sodium at 435.8 nm to

rise and match the radiation from the mercury discharge.

•l

• Lamp operating time

Time in seconds from lamp start to minimum signal

Manufacturer A

*1 h h

(hr) HPS lamp HPS lamp

No. 1 No. 2

898 87 87

951 88 87

1004 87 87

1054 85 87

1116 84 84

1178 80 79

t;

l H *2

(hr) HPS lamp HPS lamp

No. 3 No. 4

500 89 91

610 88 92

749 89 91

861 88 93

958 88 92 ; 1072 87 90

1180 85 88

Manufacturer B

*1 *2 h

(hr) HPS lamp HPS lamp

No. 5 No. 6

694 109 105

793 109 107

906 107 104

1004 107 108 ; 1095 105 117

1165 122 122

*1 t

2 *2

(hr) HPS lamp HPS lamp

No. 7 No. 8

500 115 110

610 114 110

749 115 110

861 115 110

958 116 110

1072 118 113

1180 128 130

36
Table V. Repeatability of HPS lamp reliyhtiny.

*

v

: luminous flux, *

e

: radiant flux (relative),

%: relative difference from mean

o: standard deviation

o : fractional standard deviation

Date

Lamp No. IS Lamp No. 2S Lamp No. 3S

v (lm) % *e % *

v (lm) % *e %

v (lm) % *e %

3/3-3/5

3/21 4/2-4/3

4/8-4/9

4/28

5/5-5/6

6/9 6/16 6/19-6/23

6/25-6/26

51310

50910

51410 51480

51430

51470 51620

51130

51380

51630

-0.14

-0.91 +0.06

+0.19 +0.10

+0.18

+0.47

-0.49

+0.49

3.431 3.406 3.463

3.429 3.436

3.433

3.449

3.435

3.461

3.455

-0.26

-0.99

+0.67 -0.32 -0.12

-0.20

+0.26 -0.15

+0.61

+0.44

48830 49030

49230

49250

49470 49360

49230

49070

49180

49400V.

-0.77

-0.37 +0.04

+0.08

+0.53

+0.30 +0.04

-0.28

-0.06 +0.39

3.181

3.181 3.181 3.176

3.221 3.200

3.188

3.199 3.210

3.196

-0.38

-0.38

-0.38 -0.53

+0.88 +0.22

-0.16 +0.19 +0.53

+0.09

50630 50860

50980

51080 51000

51060

50960

50770 50920

50820

-0.55 -0.10

+0.14 +0.33 +0.18

+0.29 +0.10

-0.28 +0.02

-0.18

3.285

3.289 3.276

3.294 3.257

3.289 3.283

3.287

3.302

3.272

+0.06

+0.18

-0.21 +0.34

-0.79

+0.18

+0.12 +0.58

-0.34

mean 51380 3.440 49210 3.193 50910 3.283

a 218.5 0.0174 190.2 0.0146 139.7 0.0126

°° 4.25xl0- 3 5.06xl0- 3 3.87*10- 3 4.56xl0- 3 2.74x10-3 3.82xl0-3

Date

Lamp No. 4S Lamp No. 5S Lamp No. 6S

*

v (lm) % *e % *

v (lm) % *e % *

v (lm) % *e %

3/3-3/5

3/21 4/2-4/3

4/8-4/9

4/28 5/5-5/6

6/9 6/16 6/19-6/23

6/25-6/26

50090

50200 50220

50470

50320

50330 50480

50400

50250

50380

-0.44

-0.22 -0.18 +0.32

+0.02

+0.04

+0.34 +0.18

-0.12 +0.14

3.282 3.283

3.289 3.276

3.286 3.298

3.289 3.278

3.286

3.290

-0.12 -0.09

+0.09

-0.30

+0.37

+0.09

-0.24

+0.12

51130 51270

51660

51490

51480

51470 51470

51230

51380

51430

-0.53

-0.25 +0.51 +0.18

+0.16

+0.14

+0.14

-0.33

-0.04

+0.06

3.333 3.346

3.369 3.339

3.370

3.345 3.350

3.357 3.369

3.354

-0.60

-0.21 +0.48

-0.42

+0.51 -0.24

-0.09 +0.12

+0.48

+0.03

51370 51420

51690

51580

51750 51620

51580

51380

51580 51530

-0.35

-0.25

+0.27 +0.06

+0.39 +0.14

+0.06

-0.33 +0.06

-0.04

3.362

3.374 3.368

3.387 3.364 3.380

3.367 3.366

3.378

3.382

-0.33 +0.03

-0.15 +0.42

-0.27

+0.21 -0.18

-0.21 +0.15 +0.27

mean 50310 3.286 51400 3.353 51550 3.373

a 124.7 6.38x10-3 153.4 0.0131 127.3 8.59x10*3 —

——

2.48x10-3 1.94x10-3 2.99x10-3 3.90x10-3 2.47x10-3 2.55xl0- 3

37
Table V. (Continued)

Date

Lamp No. 7S Lamp No. 8S Lamp No. 9S

*

v (lm) % *e % *

v (lm) % *e °l° . »

v (lm) % *e %

1/31 3/3 3/24-3/25

4/21-4/25

5/2 5/5-5/6

6/10

6/17

6/20

6/24-6/25

49730 49630

49690

49800

49470 49750

49700 49780

49530 49670

+0.10

-0.10 +0.02

+0.24

-0.42 +0.14

+0.04

+0.20

-0.30

-0.02

3.413

3.401 3.403

3.412

3.391 3.387

3.405

3.407

3.404 3.417

+0.26

-0.09

-0.03 +0.24

-0.38

-0.50

+0.03 +0.09

+0.38

50230 50390

50310 50350

50120 50550

50360

50360

50220

50390

-0.20

+0.12

-0.04 +0.04

-0.42 +0.44

+0.06

+0.06

-0.22 +0.12

3.430

3.441

3.435 3.427

3.399

3.436 3.425

3.425

3.429

3.444

+0.03

+0.35 +0.18

-0.06

-0.82 +0.20

-0.12

-0.12

+0.44

49840 50130

50300

50490

50270 50040

50310 50310

50300

50250

-0.76

-0.18

+0.16

+0.54 +0.10

-0.36 +0.18

+0.18

+0.16 +0.06

3.482

3.441 3.459 3.465

3.436 3.448

3.466 3.462

3.459

3.468

+0.66

-0.29

+0.17

-0.66

-0.32 +0.20

+0.09

+0.26

mean 49680 3.404 50330 3.429 50220 3.459

106.0 9.38xl0- 3 117.5 0.0124 179.5 0.0136

a

o 2.13xl0- 3 2.76x10-3 2.34x10-3 3.63x10-3 3.57x10-3 3.95xl0- 3

Date

Lamp No. 10S Lamp No. US Lamp No. 12S

•

v (lm) % 4*e % •

v (lm) % *e % *v (1m) % *e %

1/31 3/3 3/24-3/25

4/21-4/25

5/2 5/5-5/6

6/10

6/17

6/20 6/24-6/25

49730

49780

50010

50250

50140 49740

50090 49980

49980

49850

-0.46

-0.36 +0.10

+ 0.58 +0.36

-0.44 +0.26

+0.04

+0.04 -0.22

3.370

3.377 3.380 3.422

3.399 3.385

3.415

3.413

3.414 3.412

-0.85

-0.65 -0.56

+0.68

-0;41 +0.47

+0.41 +0.44

+ 0.38

48970

48930

48730

49130

49010 48930

48710 48930

48780

48870

+0.14

+0.06

-0.35

+0.47

+ 0.22 +0.06

-0.39

+ 0.06 -0.25

-0.06

3.317 3.349

3.312 3.342

3.332

3.316

3.312 3.350

3.335

3.342

-0.42

+0.54

-0.57 +0.33 +0.03

-0.45

-0.57 +0.57 +0.12

+0.33

47520 47850

47670

47350 47540

47600

47690 47450

47780

47680

-0.19 +0.50

+0.13

-0.55 -0.15

-0.02 +0.17

-0.34 +0.36 +0.15

3.314

3.297

3.307 3.272

3.291 3.309

3.313 3.290

3.312

3.310

+0.36

-0.15 +0.15

-0.91 -0.33

+0.21 +0.33

-0.36 +0.30

+0.24

mean 49960 3.399 48900 3.331 47610 3.302

177.1 0.0190 130.3 0.0152 153.1 0.0137

°o 3.54x10-3 5.60x10-3 2.67xl0- 3 4.56x10-3 3.22x10-3 4.15x10-3

38
Table V. (Continued)

lamp voltage,

lamp current,

r c: correlated color temperature

%: relative difference from mean

Lamp No. IS

V(V) % 1(A) % T

c (<)

98.8

99.5

100.1

98.7

98.7

98.6

99.4

100.1

99.8

99.9

-0.60

+0.10

+0.70

-0.70

-0.70

-0.80

+0.70

+0 40

+0.50

4.704

4.674

4.657

4.709

4.711

4.719

4.693

4.654

4.672

4.664

+0.38

-0.26

-0.61

+0.49

+0.53

+0.70

+0.15

-0.68

-0.30

-0.47

2057

2083

2023

2074

2062

2084

2095

2110

2089

2077

99.4 4.686 2075

0.611 0.0243 24.0

6.15xl0- 3 5.18xl0" 3 1.15xl0- 2

Lamp No. 2S

V(V) % 1(A) % Tc(K)

92.4

91.8

92.0

92.3

92.3

92.1

92.2

93.0

92.6

92.5

+0.11

-0.54

-0.33

-0.22

-0.11

+0.76

+0.33

+0.22

4.972

5.015

5.002

4.989

4.997

5.007

5.006

4.965

4.978

4.985

-0.40

+0.46

+0.20

-0.06

+0.10

+0.30

+0.28

-0.54

-0.28

-0.14

2066

2090

2081

2094

2051

2091

2100

2110

2093

2087

92.3 4.992 2086

0.318 0.0165 16.9

3.45xl0- 3 3.31x10-3 8.11x10-3

Lamp No. 3S

V(V) % 1(A) % T

C

(K)

92.9

92.0

92.2

91.8

91.8

91.8

92.4

92.6

92.7

92.7

+0.65

-0.33

-0.11

-0.54

-0.54

-0.54

+0.11

+0.33

+0.43

+0.43

4.955

5.006

4.998

5.015

5.016

5.020

4.995

4.985

4.976

4.978

-0.78

+0.24

+0.08

+0.42

+0.44

+0.52

+0.02

-0.18

-0.36

-0.32

2063

2078

2084

2061

2082

2089

2102

2097

2095

2087

92.3 4.994 2084

0.425 0.0209 13.6

4.61x10-3 4.19x10-3 6.51x10-3

Lamp No. 4S

V(V) % KA) % MK)

94.0

93.6

95.8

94.1

93.7

93.5

93.8

93.7

93.7

93.4

+0.11

-0.32

+ 2.02

+0.21

-0.21

-0.43

-0.11

-0.21

-0.21

-0.53

4.900

4.929

4.819

4.902

4.922

4.929

4.927

4.929

4.930

4.940

-0.26

+0.32

-1.91

-0.22

-0.18

+0.33

+0.29

+0.33

+0.35

+0.55

2057

2083

2067

2084

2053

2033

2080

2095

2088

2090

93.9 4.913 2072

0.690 0.0353 19.6

7.34x10-3 7.18x10-3 9.47x10-3

39
Table V. (Continued)

Lamp No. 5S

V(V) % 1(A) % T

C (K)

93.3 -0.74 4.935 +0.49 2065

93.4 -0.64 4.933 +0.45 2072

93.9 -0.11 4.918 +0.14 2057

94.0 4.916 +0.10 2084

93.7 -0.32 4.923 +0.24 2039

93.5 -0.53 4.939 +0.55 2088

94.2 +0.21 4.903 -0.16 2093

94.6 +0.64 4.886 -0.51 2089

94.9 +0.96 4.878 -0.67 2089

94.6 +0.64 4.880 -0.63 2088

94.0 4.911 2076

0.555 0.0231 17.8

5.90xl0- 3 4.70x10-3 8.56x10-3

Lamp No. 6S

V(V) % 1(A) % TC

(K)

94.3

94.3

94.5

94.4

94.4

94.6

93.8

94.0

93.9

93.8

+0.11

+0.11

+0.32

+0.21

+0.21

+0.42

-0.42

-0.21

-0.32

-0.42

4.894

4.894

4.890

4.892

4.893

4.888

4.921

4.912

4.922

4.922

-0.18

-0.18

-0.27

-0.22

-0.20

-0.31

+0.37

+0.18

+0.39

+0.39

2073

2078

2085

2050

2070

2085

2098

2092

2092

2092

94.2 4.903 2082

0.297 0.0145 14.3

3.15x10-3 2.97x10-3 6.86x10-3

Lamp No. 7S

V(VJ % 1(A) % T

C

(K)

101.1

101.7

101.3

101.3

102.6

101.4

101.5

101.7

101.8

101.8

-0.49

+0.10

-0.30

-0.30

+0.98

-0.20

-0.10

+0.10

+0.20

+0.20

4.599

4.571

4.595

4.600

4.539

4.598

4.590

4.587

4.581

4.578

+0.33

-0.28

+0.24

+0.35

-0.98

+0.31

+0.13

-0.07

-0.07

-0.13

2055

2064

2067

2027

2057

2075

2075

2083

2076

2074

101.6 4.584 2065

0.418 0.0185 16.1

4.12x10-3 4.04x10-3 7.81x10-3

Lamp No. 8S

V(V) % 1(A) % T

C (K)

100.2

100.3

100.3

100.7

100.7

100.5

100.0

99.9

100.3

100.2

-0.10

+0.40

+0.40

+0.20

-0.30

-0.40

-0.10

4.639

4.638

4.636

4.624

4.626

4.635

4.656

4.660

4.644

4.649

-0.04

-0.06

-0.11

-0.37

-0.32

-0.13

+0.32

+0.41

+0.06

+0.17

2066

2055

2073

2069

2085

2073

2085

2092

2082

2079

100.3 4.641 2075

0.264 0.0118 10.6

2.64x10-3 2.54x10-3 5.09x10-3

40
Table V. (Continued)

Lamp No. 9S

V(V) % 1(A) % MK)

106.0

104.3

103.8

104.4

103.8

104.3

104.0

103.9

103.8

103.5

+ 1.34

-0.29

-0.76

-0.19

-0.76

-0.29

-0.57

-0.67

-0.76

-1.05

4.414

4.471

4.497

4.476

4.492

4.480

4.490

4.502

4.501

4.511

-1.54

-0.27

+0.31

-0.16

+0.20

-0.07

+0.16

+0.42

+0.40

+0.62

2041

2079

2063

2053

2081

2074

2078

2085

2068

2075

104.2 4.483 2070

0.699 0.0274 13.8

6.71xl0- 3 6.11xl0- 3 6.67xl0- 3

Lamp No. 10S

V(V) % 1(A) % T

C U)

101.5

101.5

101.0

101.6

101.5

101.3

101.2

101.8

101.8

101.4

-0.49

+0.10

-0.20

-0.30

+0.30

+0.30

-0.10

4.583

4.581

4.608

4.586

4.588

4.596

4.599

4.579

4.577

4.590

-0.13

-0.17

+0.41

-0.07

-0.02

+0.15

+0.22

-0.22

-0.26

+0.02

2090

2086

2069

2047

2075

2081

2078

2087

2067

2079

101.5 4.589 2076

0.250 0.0098 12.6

2.47x10-3 2.14x10-3 6.07x10-3

Lamp No. US

V(V) % 1(A) % T

C

(K)

101.7

101.7

101.8

101.2

100.8

100.7

100.7

101.9

102.3

102.1

+0.20

+0.20

+0.30

-0.30

-0.69

-0.79

-0.79

+0.34

+0.79

+0.59

4.569

4.569

4.569

4.597

4.607

4.614

4.618

4.575

4.557

4.562

-0.33

-0.33

-0.33

+0.28

+0.50

+0.65

+0.74

-0.20

-0.59

-0.48

2084

2047

2082

2052

2044

2075

2079

2074

2084

2064

101.5 4.584 2069

0.595 0.0229 15.6

5.86x10-3 5.00xl0- 3 7.56x10-3

Lamp No. 12S

V(V) % 1(A) % T

C (K)

103.8

103.6

103.5

104.7

104.5

104.4

103.8

103.6

103.5

103.6

-0.10

-0.29

-0.39

+0.77

+0.58

+0.48

-0.10

-0.29

-0.39

-0.29

4.501

4.505

4.512

4.474

4.479

4.480

4.506

4.514

4.519

4.513

+0.02

+0.11

+0.27

-0.58

-0.47

-0.44

+0.13

+0.31

+0.42

+0.29

2022

2052

2040

2086

2086

2072

2076

2081

2064

2076

103.9 4.500 2066

0.455 0.0165 20.3

4.38x10-3 3.67x10-3 9.81xl0- 3

41
Table VI Total luminous fluxes $v and the correlated color

temperature of 12 stable HPS lamps

Lamp No $v(lm) (K)

12

34

5

6

7

89

10

11

12

51480 2080

49310 2090

51010 2080

50410 2070

51500 2080

51650 2080

49780 2070

50430 2080

50320 2070

50060 2080

49000 2070

47710 2070

42
References

[I] Louden, W.C. and Schmidt, K. , "High pressure sodium discharge arc lamps" 111. Eng. 60 (12), 696, (1965).

[2] Otani, K. , Kawahara, K. , Watanabe , K. , and Tsuchihashi, M. , "A high

pressure sodium lamp with improved color rendition" Journal of IES

11 (7), 237, (1982).

[3] McVey, C.I. , "High Pressure sodium lamp technology" IEEE Proc .

,

127 . pt. A (3), 158, (1980).

[4] Wharmby, D.O. , "Scientific aspects of the high pressure sodium

lamp" ibid, 127 pt. A (3), 165, (1980).

[5] Van Vliet, J.A.J.M. and de Groot, J.J., "High pressure sodium

discharge lamp" ibid., 128, pt. A (6), 145, (1981).

[6] Akutsu, H. , "Trends in HPS lamp technology" Lighting Research and

technology 16 (2), 73, (1984).

[7] International Commission on Illumination (CIE) , "Method of

measuring and specifying color rendering properties of light

sources" CIE Publ. no. 13, 2 (TC-3.2) (1974).

[8] Bhalla, R.S., Larson, D.A. , and Unglert, M.C., "HPS lamp with

improved color rendering" Journal of IES 8 (7), 202, 979).

[9] Akutsu, H. , Watarai, Y. , Saito, N. , and Mizuno, H. , "A new high

pressure sodium lamp with high colour acceptability" Journal of IES

13 (7), 341, (1984).

[10] Denbigh, P.L. , "Effect of sodium/mercury ratio and amalgam

temperature efficacy of 400 W HPS lamps" Lighting Research and

Technology 6 (2), 62, (1974).

[II] See for example:

Waymouth, J.F., "An elementary model of the high-pressure sodium

lamp" Journal of IES 6 (3), 131, (1977).

Akutsu, H. and Saito, N. , "Energy balance of a high-pressure sodium

arc tube" Journal of Light and Visual Environment" 3, 11, 1979.

[12] Waymouth, J.F. and Wyner, E.F., "Analysis of factors affecting

efficacy of HPS lamps" Journal of IES 10 (4), 237, (1981).

[13] Jacobs, C.A.J. , Sprengers , L. and de Vaan, R.L.C., "Arc voltage

control in low and high pressure sodium lamps" Journal of IES 7 (1), 125, (1978).

43
[14] Li, S.Z., Zhou, T.M. , and Cai , Z.Q. , "Analysis of factors affecting

the color rendition of HPS lamps" Proceedings of meeting on High

temperature lamp chemistry, Electric Chemistry Society (China)

(1985) (Edited by Zubler, E.G.)

[15] See for example:

Wyner, E. , "Electrolysis of sodium through alumina arc tubes"

Journal of IES 8 (3), 166, 1979.

[16] "Specification for 400W HPS lamps S51" ANSI C78 . 1350-1976 . "HPS

lamps - method of measuring characteristics" ANSI C78.388 - 1984.

[17] "Lamp Testing Engineer's Conference (LTEC)" Meeting in NBS

September 25, 1985.

[18] "Procedures for the measurement of luminous flux of discharge lamps

and for their calibration as working standards" CIE Publication No.

25 (1973, Reprinted 1982).

[19] "The spectroradiometric measurement of light sources" CIE

Publication No. 63, (1984).

[20] See for example:

McSparron, D.A. , Mohan, K. , Raybold, R.C., Saunders, R.D. and

Zalewski, E.F., "Spectroradiometry and conventional photometry - An

interlaboratory comparison" NBS Technical Note 559, 1970;

Nonaka, M. , Kinameri, K. , and Ishiba, M. , "Spectroradiometric

measurement on fluorescent lamps" Metrologia 8 (4), 133, (1972);

Spears, G.R., "Spectroradiometry Photometry" Journal of IES 3 (3),

229, (1974).

[21] "Specification for HID lamp reference ballasts" ANSI C82. 5-1977.

[22] Mielenz, K.D. and Eckerle, K.L. , "Spectrophotometer linearity

testing using the double -aperture method" Appl. opt. 1_1 (10), 2294,

(1972).

[23] Booker, R.L. and McSparron, D.A. , "Photometric Calibration

Services at NBS", Nat. Bur. Stand (U.S.), Spec. Publ. 250-15

(1987).

[24] "IES approved method for photometric measurements of HID lamps",

Journal of the IES 4 (3), 229, (1975).

*U.S. GOVERNMENT PRINTING OFFICE: 1988—201-597/92548

44
NBS-114A (REV. 2-8C) U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO.

NBS/TN-594/14

2. Performing Organ. Report No 3. Publication Date

August 1988

4. TITLE AND SUBTITLE

HIGH PRESSURE SODIUM DISCHARGE LAMP CHARACTERIZATION FOR USE AS STANDARDS OF

GEOMETRICALLY TOTAL LUMINOUS FLUX

5. AUTHOR(S)

Minggao He and Robert J. Bruening

6. PERFORMING ORGANIZATION (If joint or other than NBS. see instructions)

NATIONAL BUREAU OF STANDARDS

VS. DEPARTMENT OF COMMERCE

GATTHERSBURG, MD 20899

7. Contract/Grant No.

8. Type of Report & Period Covered

Final

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City, State, ZIP)

SAME AS ITEM #6 ABOVE.

10. SUPPLEMENTARY NOTES

2 Document describes a computer program; SF-185, FlPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here) The stability of commercial 400W high pressure sodium lamps has been

studied to allow the selection of lamps that produce a stable luminous

flux on relighting. The properties of the lamps have been studied during

the first minutes of starting, their output on relighting in place, and

their output after 100' s of hours burning. Lamps have been selected that

repeat to + 1% on relighting, and are expected to remain that stable over

a life of about 450 hours. The lamps have been calibrated for total

luminous flux by sphere comparison, with an uncertainty of +4.6%. These

lamps will be used as working standards, and goniometric measurements

will be made to reduce the uncertainty.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

high pressure sodium lamps; stability of HPS lamps; standard spectral flux lamps

13. AVAILABILITY

DTI Unlimited

| | For Official Distribution. Do Not Release to NTIS

[y I Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402. 2 Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

49

15. Price

USCOMM-DC 6043-P80

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