EARTH RESOURCES SURVEY PROGRAM

TECHNICAL LETTER NASA-96

Prepared by the Geological Survey for the National Aeronautics and Space Administration (NASA) under NASA Work Order No. T-65757

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https://ntrs.nasa.gov/search.jsp?R=19690018780 2020-05-23T23:32:19+00:00Z

UNITED S T A T E S Interagency Report DEPARTMENT OF T H E INTERIOR NASA-96

January 1968 GEOLOGICAL SURVEY WASHINGTON. D.C. 20242

M r . Robert Porter Acting Program Chief, Earth Resources Survey Code SAR - NASA Headquarters Washington, D.C. 20546

Dear Mr. Porter:

Transmitted herewith i s one copy of:

INTERAGENCY REPORT NASA-96

VACUUM ULTRAVIOLET MEASUREMENTS OF

REFLECTANCE AM) LUMINESCENCE FROM

VARIOUS ROCK SAMPLES*

H. V. Watts*

and

H. J. Goldman*

The U.S. Geological Survey has released t h i s report i n open f i l e s . Copies a r e available for consultation i n the Geological Survey Libraries, 1033 GSA Building, Washington, D.C. 20242; Building 25, Federal Center, Denver, Colorado 80225; 345 Middlefield Road, Menlo Park, California 94025; and 601 East Cedar Avenue, Flagstaff , Arizona 86001.

William A. Fischer Research Coordinatsr Earth Orbiter Program

*Work performed under Work Order No. T-65757 **IIT Research I n s t i t u t e , Chicago, I l l i n o i s

UNITED STATES

DEPARTMENT OF THE INTERIOR

GEOLOGICAL SURVEY

INTERAGENCY REPORT NASA-96

VACUUM ULTRAVIOLET MEASUREMENTS OF

REFLECTANCE AND LUMINESCENCE FROM

VARIOUS ROCK SAMPLES*

H. V, Watts=

and

He J. Goldman*

January 1968

Prepared by the U S . Geological Survey for the National Aeronautics and Space

Administration (NASA)

Work performed under Work Order No. T-65757 W I I T Research Ins t i tu te , Chicago, I l l i n o i s

CONTENTS

I.

XXT

m* V.

XN!tRODUCTION

MPER-AL TECHNIQUE

A. Sample Surface Preparation

8 . Instmentation C, Measurement Geometry

D. Measurement Methods and Standardization

DATA AND DISCUSSION

OBSERVATIONS

CO1\FcLUSIO,NS AND PLANS FOR WORK

REFERENCES

APPENDIX: DATA CURVES

Page

1

3

3

5

6

9

13

21

23

24

A-1

ii

LIST OF FIGURES

F i g u r e 1: Geometry for Type I Measurements

F i g u r e 2: Geometry for Type 11 Measurements

F i g u r e 3: Copper Reference Data

LIST OF TABLES

Table 1: R e f lec tance Samples

Page 7

8

11

4 r

iii

VACUUM ULTRAVIOLET MEASUREMENTS OF REFLECTANCE AND LUMINESCENCE FROM

VARIOUS ROCK SAMPLES

I. JNTRODUCTION

This s tudy i s a cont inua t ion of the work repor ted i n

"Reflectance of Rocks and Minerals t o V i s i b l e and U l t r a v i o l e t

Radiation," Technical Letter, NASA-32, Ju ly , 1966, (Ref. l), i n

which r e f l e c t a n c e da t a were obtained from 2300A t o 7000A with a

Cary Model 14 MR recording spectrophotometer u t i l i z i n g the Model

1411 d i f f u s e r e f l e c t a n c e attachment. The o v e r a l l ob jec t ive of

these s t u d i e s i s t o determine i f t he re are s i g n i f i c a n t d i f f e r -

ences i n the spectral r e f l e c t a n c e or emission from var ious

geologica l materials which may be used f o r i d e n t i f i c a t i o n and/or

d i f f e r e n t i a t i o n purposes i n remote sensing app l i ca t ions . The

two f a c t o r s which d i s t i n g u i s h the c u r r e n t study are:

1. The samples were i n an evacuated chamber during the measurements. This permitted the s h o r t wave- length range t o b e extended i n t o t h e so-ca l led

than 2000A. I n order t o f a c i l i t a t e comparison wi th the previous s tudy the s p e c t r a l region from 2300A t o 3000A w a s repeated.

"vacuum u l t r a v i o l e t , I 1 i .e . , wavelengths s h o r t e r

2. Measurements were made wi th both monochromatic and broad band sample i l l umina t ion u t i l i z i n g a corresponding broad band and monochromatic de t ec t ion .

-1-

~ - ----.-I_-

'&is permitted the separation of the reflection

and luminescence components, which was not

possible in the previous study.

-2-

I1 *

A. Sample Surface Prepara t ion

The e leven samples s e l e c t e d for s tudy

source loca l i t i es are l i s t e d i n Table 1. Each sa

t o form a one inch by one inch s l a b o f about one-quarter inch

th i ckness .

ca rb ide (30 micron p a r t i c l e s i z e ) . This su r face i s des igna ted

a s t h e ''ground" surface. The o t h e r su r face was f u r t h e r ground

wi th W 8 aluminum oxide (8 micron p a r t i c l e s i ze ) and then pol ished

wi th Linde "B" (0.05 micron) on one-quarter inch t h i c k f e l t .

This surface i s des igna ted as t h e "polished" su r face . After

g r ind ing o r po l i sh ing , t h e s u r f a c e s were r i n s e d i n absolu te '

a l c o h o l immediately p r i o r t o i n s e r t i o n i n t h e sample measure-

ment chamber. Care was taken so t h a t t h e sample s u r f a c e s were

not touched o r contaminated i n handling.

One s u r f a c e of t h e s l a b was ground wi th 320 s i l i c o n

Except f o r t h e pumice sample t h e surfaces of t h e e i g h t

rocks were t h e same as thase used i n t h e previous s tudy of

Reference 1. The pumice could riot be pol i shed because of i t s

porous v e s i c u l a r na ture . I n t h e s l a b s i z e required,the pumice

samples were somewhat f r a g i l e and, i n f ac t , t w o samples broke ,

i n t h e process of mounting i n t h e sample holder .

The meteor i te samples, e s p e c i a l l y t h e Coarse Octahedr i te ,

were more d i f f i c u l t to s i z e and work. I n t h e previous s tudy

t h e me teo r i t e was simply c u t i n t o two p a r t s , and t h e c u t s u r -

face of one p a r t w a s ground and t h e oppos i te surface p a r t of

t h e c u r t was pol ished. The requirement of a small s l a b sample

-3-

aJ d

(d P n

0 0 c *rl *vi x m

a, u *rl k 0 *rl n

0 k

P n

s U d (d VJ (d m

aJ U *rl c rt ta

c m *rl a *rl VJ P 0

-4-

t o f i t i n t o t h e vacuum sample chamber i n t h i s work required

more c u t t i n g and i n so doing the actual su r faces used were n o t

t h e same as those previously examined. The Coarse Octahedr i te

(iron-nickel) appeared as a metallic su r face which took a high

pol i sh ; t h e Hypersthene Chondrite su r face had a mott led appearance

wi th some small, shiny metallic spots.

B. Instrumentation

A Jarrell Ash Model 78-650 one-half meter scanning

vacuum gra t ing monochromator of t he Seya-Namioka type w a s used.

The g r a t i n g s i z e is 38 x 38 mm with 30,000 l i n e s pe r inch, blazed

f o r use i n t h e 500A t o 3000A range. Monochromator s l i t widths of

about 0.3 mm were used, which wi th the instrument d i spe r s ion of

17A per mm gave a band pass of about 5A.

The source w a s a Tanaka-Type c a p i l l a r y discharge tube

(Jarrell Ash Model 45-202) exc i t ing u l t r a pure (99.999%)- hydrogen

a t 15,000 v o l t s AC and 500 milliamps. A windowless configuration

w a s used, i.e., t h e source gas w a s d i f f e r e n t i a l l y pumped through

t h e en t rance s l i t of t h e monochromator. In normal opera t ion t h e

monochromator chamber pressure w a s lom3 mm Hg and t h e source chamber

w a s f i l l e d wi th hydrogen a t about 0.5 t o 1 mm pressure.

The d e t e c t o r w a s an EMI 6255B m u l t i p l i e r phototube wi th

an S-13 response. A t h i n coating of sodium s a l i c y l a t e w a s used t o

extend t h e s tandard S-13 response i n v i s i b l e and near u l t r a v i o l e t

t o wavelengths as s h o r t as 9OOA i n t h e vacuum u l t r a v i o l e t .

-5-

The associated circuitry, high voltage supply, micro-micro ammeter

and recorder, were the standard Jarrell Ash instrument package.

The multiplier phototube had a dark current of the order of 10- 11

amps at 1000 volts.

of a t least 10-

Most of the data measurements produced signals

amps so tha t the detectabil i ty was generally good. 9

C. Measurement Geometry

A vacuum tight sample chamber was constructed t o

hold s ix samples on a rotatable hexagonal wheel.

could be attached t o ei ther the entrance or exit s l i t of the

monochromator; e i ther the source o r the detector could be attached

t o the other face of the sample chamber. The hexagonal wheel per-

mitted each sample t o be rotated into measurement position. The

remaining f ive samples i n the chamber were completely masked off

from a direct view of e i ther the source or detector. A black matte

l i ne r on all inside surfaces of the chaiber served t o reduce li&t

scattering, and a l i gh t baff le was bu i l t i n t o block the direct

l i n e of sight between source and detector.

This chamber

The two types of measurement geometries are illustrated

i n Figures 1 and 2.

angles are 60 degrees t o the sample surface normal..

geometry (Figure 1) a 10 x 15 mm sample surface area is illuminated

with focused, monochromatic l ight . The sample surface is viewed by

In both geometries the illumination and detection

In the Type I

the detector though a circular aperture of 3.6 cm diameter at a

centerline distance of

-6-

-7-

v) c If w 5 w a 3 69 Q w 3E

7.4 cm between sample and detector.

sensi t ivi ty of the detector, the recorded signal i n

includes both the sample reflectance a t the i

wavelength and any ult raviolet or vis ible (up t o about 6 0 0 0 ~ )

luminescence which the incident wavelengbh excites.

Because of the broad spectral

In the ty'pe I1 geometry (Figure 2) the ent i re sample

surface i s illuminated w i t h the f'ull. hydrogen source spectrum.

The sample reflectance plus luminescence is then detected with

spectra4 select ivi ty through the monochromator. The monochromator

f i e l d of view covers a sample surface area of about 14 mm x 10 m.

Each element within t h i s surface area, however, i s detected with a

very small acceptance angle defined by the entrance s l i t of the

monochromator (0.3 mm x 10 mm) a t a center l i n e distance of 8.4

cmbetween sample and sl i t .

D. Measurement Methods and Standardization

The sample chamber was loaded w i t h ei ther f ive o r

four samples and one o r two reference materials for each se t of

measurements.

was pumped down t o

l ea s t two hours before the hydrogen gas f l o w t o the source was

The ent i re uni t , monochromator and sample chamber,

mm or l e s s pressure and outgassed for a t

begun.

the hydrogen flow the monochromator pressure i s about

the source is ignited and allowed t o stabil ize.

When a stable hydrogen gas f l o w had been reached (with

mm),

In the type I1

-9-

geometry, where the sample chamber i s between the source and the

monochromator, some different ia l pumping i s used between the

source and samples t o reduce the hydrogen content a t the samples.

Most of the data were obtained by recording the detector

signal as the monochromator was scanned from 3000A down t o lOOOA

a t a scan rate of lOOA per minute. In all cases a reference

piece of polished aluminum was i n the sample chamber and was

scanned intermittently between sample scans.

for t he sample scans were then normalized to the aluminum

reference signal at the corresponding wavelengths.

of the aluminum reference w a s primarily t o monitor the source

output., Absolute reflectance values were eventually derived on

The signal data

The fhnction

the basis of a polished copper piece which was compared t o the

aluminum reference.

( R e f . 2) for the absolute reflectance of polished bulk copper

The values of Ehrenreich and Phillipp

i n the vacuum ul t raviolet were used t o calibrate the aluminum

reference.

The detected signal (multiplier phototube current)

versus wavelength from the polished copper reference i n Ty-pe I

geometry is shown i n Figure 3. Also plotted i n t h i s figure i s

the copper spectral reflectance curve which was used as the

standard.

hydrogen source spectrum, the detector spectral response, and the

The detected signal curve shape is a function of the

sample reflectance. Two features of the hydrogen source are

prominent on all of the r a w data curves; these are the hydrogen

Lyman l i n e at U P j A and the high intensity peaks around 1600~.

-10-

I I I I

n

-11-

The f ina l standardization of tance values wa

confbed irst when a

and the copper standard

compatible w i t h t he i r li es. Further experiments

u t i l i z ing fresh aluminum copper samples were then performed

t o establish the correct reflectance value standard. These ex-

periments were successful i n explaining the early discrepancy

as being due t o a degradation of the aluminum reference sample

eflectance caused by the hard ul t raviolet radiation. Fortunately,

e original aluminum reference had been degraded during the very

checkout runs prior t o the sample data runs so tha t the aluminum

ned as a constant secondary reference t o which the copper standard

could be correlated.

To verify the reproducibility of t e s t resul ts , data on

three samples were taken twice by scanning runs on separate days

and once a t fixed wavelength points, where the wavelength was

held constant while the detected signals were measured alternately

from the samples and from reference rhaterials i n the chamber.

f i na l curves derived from these samples had essentially the same r --

e-measuremeni;s.

-12-

I11 . DATA AND DISCUSSION

I n Table 1 t h e e i g h t rocks are l i s t e d i n order of t h e

genera l ly expected decreasing si l ica content, from t h e a c i d i c

b i o t i t e g r a n i t e and r h y o l i t e t o t h e u l t r a -bas i c dunite. Deta i led

compositional and su r face t e x t u r e analyses have not been per-

formed; however, these samples are a v a i l a b l e i f such s t u d i e s

are warranted.

The normalized d a t a curves obtained f o r both Type I and

Type I1 geometries of t he same sample su r face are presented

i n the Appendix.

50 Angstrom i n t e r v a l s except f o r wavelengths near 1200 A and

1600 A where t h e source inpu t maxima produked such sharp s lopes

i n s i g n a l change on the recorded scans (see, f o r example,

Figure 3) , t h a t it w a s no t poss ib l e t o ob ta in a p r e c i s e d a t a

point.

Data po in t s wereanalyzedand p l o t t e d a t

To determine t h e f r a c t i o n of energy co l l ec t ed a t t h e

de t ec to r from t h e t o t a l emission r e f l e c t i o n by t h e rock su r face ,

t h e de t ec to r s o l i d angle w a s computed and compared

-13-

t o t he t o t a l angle of emission o r r e f l e c t i o n . The est imated

f r a c t i o n s from Figures 1 and 2 are spec i f i ed below:

a ) Type I, d i f f u s e r e f l e c t a n c e -- 0.06

b ) Type I, luminescence emission -- 0.03

c) Type 11, d i f f u s e r e f l e c t a n c e -- 2 x

d ) Type 11, liminescence emission -- 1 x 10 -4

In both geometries the sample su r face normal w a s ad jus ted

and f ixed so t h a t the source and d e t e c t o r angles t o the normal

s a t i s f i e d the l a w of Specular r e f l e c t i o n ; t h i s w a s observed

by a peaking of the response of t he de t ec to r .

detec t i q n f r a c t j o n s f o r the specu la r ly r e f l e c t e d components

are assumed t o be u n i t y f o r both geometries.

Thus the

Using the above d e t e c t i o n f r a c t i o n s we can w r i t e the

equat ions f o r the r e l a t i v e components of the de tec ted s i g n a l s .

No specular r e f l e c t a n c e component i s included i n the "ground"

su r face measurements equat ions. '

w r i t t e n below wi th the des igna t ions ( P - I > , (B-TI), ( G = I ) , and

(G-XI) wherein the symbols P and E r e f e r t o the polished and

ground sur faces , and the symbols 1 and 11 r e f e r t o the

measurement geometries,

-L

The signal. equat ions a r e

( p - 1 ) ~ = R s ( h ) + 0.06 Rd(A) -!- 0.03 LI

(P-zI)h = R,(h) 2 X Rd(A) '6 LII (2 1

(1)

A The d a t a of Reference 1 showed no s i g n i f i c a n t d i f f e rences i n ground su r face r e f l e c t a n c e curves wi th o r without the inc lus ion Qf the specular r e f l e c t a n c e component.

-14-

where :

Rs(A) = specular reflectance at wavelength A,

Rd(A) = diffuse reflectance at wavelength A, from

Rt(A) = diffuse reflectance at wavelength A, from

the polished surface,

the ground surface, ’

= luminescence excited by narrow band (5A) energy increment at A and detected with broad band detector, and

LI

= luminescence excited by direct broad band source and detected with narrow band (5A) resolution at A .

LII

The L signal component as a function of wavelength I is the luminescence excitation spectrum. In general for

mineral or inorganic luminescent materials, the excitation

spectra will have a threshold and then increase as the wave-

length decreases to a nearly constant efficiency over a broad

range of wavelengths.

The LII signal component as a function of wavelength

is the luminescence emission spectrum. Luminescence emission

will occur at longer wavelengths than the excitation wavelength.

In a simple luminescent system the emission spectrum is a

band with a width at half maximum intensity of several hundred

Angstroms. Materials such as rocks may

-15-

have several overlapping emission bands and a very broad and/or

complex spectrum.

Examination of t he components c a n t r i b u t i n g t o the

normalized measured q q a n t i t i e s ( lef t -hand s i d e s o f gquations

1 - 4 ) , l e s d s t o t h e following:

1, d i f f u s e (Rd) and luminescence (‘LII)contributions t o the (P-11) measurements, E q u a t i w 2, tend t o remove these con t r ibu t ions i n t h i s meapuremqnt. Therefore, i t i s highly l i k e l y t h a t the (P-11) curves shown i n t he Appendix e x h i b i t predominantly the specular r e f l e c t a n c e p rope r t i e s of the pol ished rock samples.

2. The (G-11) datq curves are the v o s t favorable sources of information f o r d e t e c t i n g luminescence. The ground-surface measurements, Equations 3 and 4 , remove a major con t r ibu t ion from Specular r e f l e c t i o n , i n c o n t r a s t t o those from the polished sur face , Equations 1 and 2. Thus, the ground-surface measure- ments leave only the d i f f u s e r e f l e c t i o n component t o compete with the luminescence emission in da ta i n t e r - p r e t a t i o n . can b e deduced d i r e c t l y from Equations 3 and 4 ; the e f f e c t s of d i f f e r i n g source i n t e n s i t i e s emplayed i n the two geometries have been removed i n phese equations by normalizat ion of the (G-I) and (6-11) values measured.

The extremely small c o e f f i c i e n t s modifying the

A comparison of the LI and LII i n t e n s i t i e s

Solving Equations 3 and 4 simultaneously t o remove the 1 d i f f u s e ref leCtgnce con t r ibu to r , Rd, one obta ins ,

For a l l rock samples inves t iga t ed , the normalized da ta valves

-16-

indicate that,

(GI) 43(GII) ( 6 )

So that, i n a l l cases LII is greater than LI and th

which indicates the advantage of the (G-TI) data curves over

the (G-I) data fo r detection of lumlhescence. The Appendix

curves for the ground surfaces tend to corroborate th i s since

the Type I1 geometry data exhibits considerably more peaking

than does the Type I data.

as probable evidence of luminescence.

Such peaking has been interpreted

-17-

Polished Surface - Type I Geometry: 1000-1800 A, a

l a r g e continuous inc rease i n va lue wi th i n f l e c t i o n s around

1400 and 1600; 1800.-2000 A, a broad maximpm; 2000~3000 A, a

moderate continuous decrease i n value.

Groupd Surface - Type I Geometry: 1000-2000 A; similar

t o Pol ished - Type 11; 2000-3000 A values increase with gradual

s lope ( e s s e n t i g f l y an invers ion of Polished - Type I1 behavior).

Ground Surface - Type I1 Geometry: Note t h a t these

s i g n a l s are r e l a t i v e l y low and s u b j e c t tQ larger errors i Q da t a

poin ts . There i s a resolved maximum peals q t 2400 A i n a l l

samples and a pecondary maximum around 1800 A, An i n f l e c t i o n

o r peaking a t 2050 is also ind ica t ed . Any s t r u c t v r e i n curve

shape below 1700 i s quest ionable .

2. Group 2 - Monzonite, d i o r i t e , obs id ian

Pol ished Surface - Type I1 Geometry: 1000-2050 A,

continuously inc reas ing va lues r i s i n g t o a sharp peak a t 2050;

2050-3000, same as Group I.

Polished Surface - Type I Geometry: 1000-1800 A, a

very pronounced maximum peak about 1650; 1800-3000 A, same

as Group 1.

Ground Surface - Type 1 Geometry: gene ra l ly similar

t o Group 1 except f o r obsidian whose value s t a y s about cons t an t

from 1800-3Q00 A.

Grwmd Surface - Type 11 Geometry; p m z o n i t e and

d i o r i t e have t h e i r mqximum peak a t 2050 with an i nd ica t ion of

-18-

a secondary peak around 2400.

similar t o Group 1, i n contrast t o i t s polished surface

behavior.

3. Rhyolite and Gabbro

Obsidian's curve shape is

Polished Surface - '.r5pe I1 Geometry: rhyolite tends

toward Group 2 shape while gabbro tends toward Group 1 I shape.

Polished Surface - Type I Geometry: Both samples look

most similar t o Group 2 curves.

Ground Surface - Type I Geometry: similar t o Group 1

shape rhyolite has a sharp break a t 2400 with a very strong

increase up t o 3000.

Ground Surface - Type I1 Geometry: same as Group 1

curves . 4. Eunice

m e I Geometry: generally similar curves t o Group 1.

Type I1 Geometry: the pumice surface nuItiber 3 (see

curve (1, 3) f i t s the Group 1 curve shape; pumice surface

number 2, however, has an anomalous &ape intermediate t o the

two basic groups.

5. Meteorites - Hypersthene Chondrite and Coarse

Octahedrit e

As mentioned ear l ie r these samples had surfaces different

I fromthe rocks. Also the measurements were only performed i n

the point by point technique a t 100 A intervals.

w e r s t h e n e Chondrite (mottled surface): Type I

geometry between 1000-2600 A appears similar t o Group 1 - ground

su r face d a t a wi th a sharp inc rease around 1800; 2600-3000,

va lues decrease similar t o pol ished su r face rock da ta . Type TI

geometry curve i s unique wi th a broad maximum peaking a t 2300 A.

Coarse Octahedr i te (high meta l - l ike po l i sh ) : Type I

geometry curve appears l i k e a pol ished metal r e f l e c t a n c e curve,

no te the high r e f l e c t a n c e va lues , Type I1 geometry curve does

i n d i c a t e some poss ib l e s t r u c t u r e , more d a t a po in t s would be

necessary to confirm t h i s .

-20-

IV. OBSERVATIONS

1. All qamples, both groun

reflectance values a

between 1000 A tQ 200

between 1400 A and 2000 A,

2. As the wavelength increases from 2000 A t o 3000 A, the

spectral reflectance decreases for polished surgaees and

increases f o r ground surfacse;. The largest: r e l a t ive dltffewences

i n slope values o f the curves occur for the gFound surfaces.

3 .

in that one o r more re la t ive ly aharp peaks and changes i n

slope direct ion @re common for a l l ground surfaces.

sharp peaks and chapges i n slope are noted for the polished

surfaces. These and other simPZarities i n gross aspects of

the curves suggest that surface texture ra ther than composition

a re major factors i n determining spectral reflectance, par t ie-

ular ly a t wavelengths shorter than 2000 A.

The gross aspects o f the ground Surfaces are similar

Fewer

4. The general curve charac t e r i s t i c s for monaonite and

d i o r i t e a re markedly similar to each Qther, and lgkewise,

markedly diss imilar ta rocks of more acidic and basic composition,

However, cuwe character is t ics of other rock types bear no

relat ion to composition. F Q ~ example, curves for polished

b i o t i t e grani te are more siprilar t o curves fgn dunite, an

ult rabasic rack unrelated compositionally, than they are t o

rhyol i te which f s composttionally similar to granite.

-21-

5. A l l rocks showed a luminescence emissgon at about

2400 A, while monzopiteand diarite had their peak

at 2050 A.

distinctly exciting luminescenqe, but withaut a correlation

with the emission bands it is not possib le to estimate the

observable emission under solar illumination.

The high source htenslty around 1600 A was

-22-

v. CONCLUSXONS AND PLANS FOR FUTURE WORK

Although i n i t i a l analyses o f monzonite and d i o r i t e a t

wavelengths shorter than 3000 A spggest a correlat

composition and UV spectral response, other rock samples of

more acidic and basic composition displayed l i t t l e or no

correspondence with the i r spec t ra l reflectance curves. Qui te

possibly t h i s lack of correspondence i s due to dLEferences i n

surface texture between the sample surfaces. Although ident ica l

abrasives were used t o prepare a l l sample surfaces, i t i s

possible that: the standard roqk polgshing methods used axe

inadequate, especial ly a t wavelengths shorter than 20QO A

where i r r egu la r i t i e s i n the surface may be comparatively

large with respect t o wavelength,

It is also poagible tha t surface preparation of the

samples may somehow modify the mqlecular s t ruc ture of the

surface layer so t h a t the emlqsion spectrum i s albered o r

quenched. It would be desirable i n fucure work fp include

several samples ranging from highly polished to f ine ly powdered

(-50 A), prepared from the same specimen, i n order tha t the .

e f fec t of surface texture QII both reflqctence and emission

may be studied,

1.

2 . B. Ehrenreich and H. R . Phillfpp

Thorps, C . M. Alexaqder, a iminary Ultraviolet Reflecf a l s from 200Q A tg 3000 A'', Technical Letter 37, Artgust: 1966,

A g and Cu", Phys. Rev. 128, No.

4 , Norman N. Greenman, e t . a l . , "Feasibility Study of the Ultraviolet Spectral Analystg of the Lunar Surface", Douglas Report SM-68529, March 1965.

-24-

APPENDIX - DATA CURVES

A

APPENDIX Table o f Cantqnts

DATA CURVES:

B i Q t % t @ granite , polished

ground

Rhyolite, polished

ground

Monz oni t e , p o 1 i s bred

grovnd

Diorite, p Q l i s h e d

ground

Gabbro, polished

ground

Basalt, polished

grQund

Dunite, polished

ground

Obsidian, polished

grqund

PufniceJ (designbted 1, 3)

% Pumice, (designated 2, 2)

Hypersthene chondrite, mottled surface

Coarse octakedrite, high polished surface

Pane

A- 1

A- 2

A-3

A-4

A-5

A=-6

A-7

A-8

A-9

A- 10

A-11

A - 1 2

A-13

A- 14

A- 15

A-16

A-17

A-18

A-19

A-20

. *'i : . .. . i ' . . . .. . I . . .

33N33S3NIWnl t 33NW1331338 lN33kI3d i - .

A- 1

!!? t !E . -

.. . :

33N33S3NlWnl t 33NWi33133U lN33U3d

A- 3

-. . . . . .

t

f 33NW1331338 lN3383d . .

A-4 -

A-5

A-6

33N33S3NIWfll t 33NW1331338 l N 3 3 8 3 d

A- 7

I

.- 3 3 N i X 3 N I W n l t 33NW1331338 lN3383d

I

A- 8

v) H 0 a t- v) (3 2

z 1 t- (3 z W -i W

a -

3 3

3 3 N 3 3 S 3 N I W n l t 3 3 N V L 3 3 1 d 3 8 l N 3 3 8 3 d

A-9

. . .

cv 0 - CD t

33N33S3NlNfll t 33NW1331338 -1N3383d

N

A- 10

... c.'

. I C

33N33S3NIWnl t 33NV133133kJ lN3383d

A-12

33N33S3 N I Wnl

. .

A- l.4

.. . . .

t E * - . . ' t

33N33S3NiWnl t 33NW1331338 lN3383d.

A-15

. . ... ...

t:.: .... ::

- . .- . ~ . .. . . . . . . . ,_ . . . . I . . . ._, . . . . . . .......

. . . . . . . ... - . . . . . . . . . - . _ . a _ . . . - . . . . . .L - .. .

. . . . . . . . . . . . . . . .... -. . . . . . . . . .../_.. . . . _ . . I . . - , . . _. . . _ . _ . . - .- -..- . a - .. . . . . . . z . . . . . -

. . ':. .:i. .: : . -

7

0 t c

33N33S3NIVUfll t 33NW133lJ3ii lN3383d

0 = c

A-16

._,-;. . .

- .. .. . . . . . . . . - . . . . . ,. . . ."-- .- _ . . _ I . . . . . . .. .

'1 .:: . 1:' ,_

33N33S3NiNfll t 33NV1333338 lN3383d . . . ..

A-17 .

33N33S3NIWnl t 33NU133lJ38 lN3383d.

A-18

- . -_ I.. I. . . .

c

0 0

0

N $2

0 0 W N

0 0 25

0

e4 8

0 0 8

0

-

0

!i!

0 0 s

0 8 -

0 0 P

33N33S3NlWnl t 33NW133733kJ lN33q3d . .- -

A-19 . . .

.. . A-20

- I -

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