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TABLE OF CONTENTS

Page
1. INTRODUCTION.
1
2. DESCRIPTION OF EXPERIMENTAL
PHOTOFLASH DEVICES
2
2.2 2.1 Photoflash Cartridge, Type SDE Photoflash Cartridge, Type S 2222
2.3 Photoflash Shell, Type SS
2.4 Photoflash Shell, Type SSDE
3. DESCRIPTION OF EXPERIMENTS
5
3.1 Experimental Arrangement . .
3.2 Detector Calibration .5
3.3 Experimental Errors
6
4. EXPERIMENTAL RESULTS
9
4.1 Comparison Between Reported and
Measured Output of Type III Mixture
4.2 Comparison Between Charges 6
9
5. DISCUSSION OF POTENTIAL FLASH
BLINDNESS EFFECTS
17
5.1 Permanent Eye Damage
5.2 Recovery Time to Light Flashes 17
19
5.2.1 Review of Flash Blindness Experiments .
5.2.2 Additional Observations 19
5.3 Interpretation of Results 22
5.3.1 Illumination of Photoflash . 24
5.3.2 Estimated Eye Effects 24
24
6. CONCLUSIONS
31
6.1 Cartridge Design
6.2 Photofla sh Mixture 31
6.3 Data Intorpretations 31
31
REFERENCES
32
APPENDIXI
33

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1. INTRODUCTION

The objective of this investigation of pyrotechnic light sources was confined primarily to the cvaluation of output illumination levels, the factors controlling them and comparisons with the existing criterla for optical incapacitation, since these considerations detcrmine the suitability of such a system to a variety of possible weapon applications.

The effort was directed primarily at comperisons of existing threshold energies for incapacitation and damâge, pyrotechnic output energies, and the fabrication of test. devices with controlled parameters, followed by estimation of their output energies by means of appropriate instrumentation. The approach permitted a comparison with existing data on energy levels corresponding to optical incapacitation and damage. This comparison was used to obtain first order estimates of the effective. ranges at which these pyrotechnic illumination devices would either incapacitate or permanently damage exposed personnel.

The four pyrotechnic light mixtures shown in Table I were evaluated during this investigation. In the followving sections there are presented the methods and techniques employed, results obtained, and the conclusions regarding the feasibility of this approach.

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2. DESCRIPTICN OF EXPLRIMENTAL PHOTOILASH DEVICES

A bricf description of the charges was included in thc Final Summary Report - Part I. Two basic photoflash cartridges wero employed. Design drawings of those cartridges are presented in Figures 1 and 2. The performance of each of the four selectcd pyrotechnic mixtures wa's evaluated in each cartridge design. The specifications of each of the mixtures were previously described (see Reference 1).

2.1 PHOTOFLASH CARTRIDGE, TYPE S

The outer diameter of the Type S photoflash cartridge is 2.7 in. and the length is 6.6 in. The outer shell is made of aluminum. A scale drawing of the cartridge is shown in Figure 1. A linear charge of DuPont PETN primacord, .22 in. diameter and 5.25 in. long, was surrounded by the photoflash mix. This central bursting charge was used to break the casing, and to ignite and disperse the pyrotechnic mixture.

2.2 PHOTOFLASH CARTRIDGE, TYPE SDE

This cartridge was identical to the type S with the exception that DuPont Deta sheet explosive was wrapped around the exterior cylindrical wall of the Type S cartridge. These sheets were cut, as shown in Figure 1, to permit the complete coverage of the outer wall. The purpose of this design was to compact the photoflash mixture first before it was disseminated, in an attempt to improve the light output (i.e., as discussed in the last progress report, the rate of burning and light output should increase with the degree of charge compaction). The ignition train was designed so that the Deta sheet would be detonated before the central bursting charge. ·華

2.3 PHOTOFLASH SHELL, TYPE SS

The Type SS shotgun shell has an O.D..of 0.853 and a length of 3.20 in. It is also made of aluminum. Except for dimensions, this photoflash shell design is similar to the 2.7 in. photoflash cartridge (see Figure 2).

2.4 PHOTOFLASH SHELL, TYPE SSDE

This shcll is identical to the Type SS, with the exception that 'Dupont Dəta sheet is wrapped around the cylindrical body in a similar manner as the SDE.

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3. DESCRIPTION OP EXPERIMENTS

Thc cxpcrimcntuil tcchniques employed and the spccific experiments performed arc outlined in this scction.

3.1 EXPERIMENTAL ARRANGEMENT

The intensity of the light output as a function of time wås measurcd and rccorded using a silicon photodiode (United Detcctor Technology Inc.. PIN-10) and a Tektronix 535 oscilloscopc with a Polaroid film attachment. The PIN-10 photodiode has a half-value response between 3600 and 10500 Å. The photodiode, PIN-10, was protccted from fragments generated from the explosive dissemination bs a metal shield. The light from the flash was indirectly focused anto the PIN-10 sensor using a mirror.

A Corning 1-56 filter was placed in front of the PIN-10. This filter has transmissicn charácteristics similar to the eye response. It has a near gaussian trans mission curve between 3600 and 7000 Å with a peak transmission at 5200 A. The ultreviolet is cut-off at 3600 A and less than 10% of the I-R radiation (i.e., between 1 and 4.5 microns) can be transmitted through this filter. Depending on the expected output of each test device, noutral density filters were also used so that the PIN-i0 would operate within its linear response regime (i.e., so that light intensity versus output voltage would remain linear).

The output signal from the sensor was fed into a Tektronix 535 oscilloscope with a 50 ohm termination. The signals were permanently recorded using a Polaroid camera attachment. The oscilloscope and event were triggered using a 5 KV firing panel.

The events were also monitored photographically. A speed graphic single exposure camera and a Beckman & Whitley Dynafax motion picture camera werc used with Polaroid filters. The Dynafax camera was operatud at a framing rate of 3000 frames per second.. Both cameras were protected from the blast. The Dynafax camera was located behind a barricade and received the light from the photoflash via a front suriace mirror. The speed graphic camera was located behind thick glass.

3.2 DETECTOR CALIBRATION

The PIN-10 photodetector was calibrated using a National Bureau of Standards certified light scurco. The response of the detector was measured as a function of distance away from the standard source using the following equation

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$$
I = x \cdot F \cdot v \cdot D ^ { 2 }\tag{1}
$$

where

I is the intcnsity of the light source in candle-power,

K is the calibration factor, 2640 foot-candles pcr 38.07 millivolts response,

F is the factor which compensates for the transmission of the neutral density filters,

y is the output signal, volts, generated by the photodetector, and

D is the opticał distance between the PIN-10 photodetector and the light source.

The spectral response characteristics of the photodetector are shown in Figure 3. The relative spectral sensitivity of the PIN-10 with the Corning 1-56 filter was calculated. These results are presented in Figure 4.

The optical distance between the light sources and the photodetector was 23.5 feet in each experiment. The intensity of the source expressed in candle-power was calculated using Eq. (1). The values of candle-power estimated can be interpreted directly in terms of the luminous flux traveling through a normal plane which intersects the light path 1 foot away from the source (i.e., the density of luminous flux incident on a normal surface one foot away from a 1 candle-power source is 1 lumen/ft2).

3.3 EXPERIMENTAL ERRORS

An experiment was performed to determine the amount of light received by the photo-detectors via wall reflection. A General Electric No. 22 photoflash bulb was placed 23.5 ft. away from the photo-detector in a similar manner as were the photoflash pyrotechnic test devices. Black paper was placed directly in front of the flash bulb to prevent direct light transmission to the photo-detector. When compared with a control . test in which the light barrier was not used, it was calculated that less than 5% of the light receivcd by the photo-detector was due to light reflcctlons from the walls of the test chamber. As a precaution, in subsequent tests, all light colored objects were rémoved from the test chamber before each experiment. The walls of the chamber were washed down after cach test, also, to remove any dcbris which might increase the light reflection.

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4.EXPERIMENTAL. RCSULTS

The measurcd outputs versus tinc for each of the expcrimontal photoflash dovices are shown in Figurcs 5 through 8. These figures were drawn from the oscilloscope traces obtained in each experiment, The results of cach photoflash cartridga design wcre combined so that a ready comparison could be made regarding the ralative períormance of the light output from each of the four pyrotechnic mixtures. The peak light intensities, the half width of intensity-time and the total integrated area under each curve (i.e., total light output in candie-power-seconds) are reported in Table II. The maximum cloud size generated by each device is also included in this table. The latter data was obtained from the . film records taken.

4.1 COMPARISON BETWEEN REPORTED AND MEASURED OUTPUT OF TYPE III MIXTURE

Mixture A has a composition identical to the standard Type III (i.e., mixture A) photoflash mix. This Type III photoflash mixture has previously been used in a variety of standard photoflash cartridges. Light output data was obtained for this mixture,² from other sources, and is summarized in Figure 9. The peak intensities and integrated candle-power-seconds total output are plotted as a function of charge size in pounds. Approximations of best-fit curves were drawn through each set of data as shown. The arrow on the abscissa represents the charge weight of the pyrotechnic mixtures in the Type S cartridge, 1.4 lbs.

The predicted peak intensity and total output for this charge are, respectively, 2.3x108c. p. and 4.4x106c.p.s. The experimental values obtained durinġ the tests on this program were 1.?6x l08 c.p. and $2 . 0 \times 1 0 ^ { 6 } < . 0 . 3$ .(see Table Il). These data are consideid to be in reasonable agreement and provide an additional check on the : curacy of the measuring techniques and the charge preparations.

4.2 COMPARISON BETWEEN CHARGES

Based on the peak intensity data, the overall performance of the Type A mixtures in the various shelis was the best. In order of decreasing performance it was found that

$$
A > C > B > D
$$

The peak intensity of the output however is not -the only critcrion that should be used in evaluating the performance of a mixture for this application. The duration of the light pulsè is of equal importance. From

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TALLE II. SUMMARY OF TEST RESULTS

\*S and SDE refer to the type of photoflash cartridge used. A, B, C and D refer to the pyrotechnic mixture used (see Table I).

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the plots of intensity versus timc it was sliown that the light pulses from the ${ \mathfrak { i } } _ { \mathbf { C } ^ { n } }$ mixture were in most cases of longcr durution. Bascd on the total integratcd light output the $\ " \mathtt { v } _ { \mathbb { C } ^ { \sharp } }$ and $\because \Delta ^ { \circ }$ mixtures were equally effcctive.

$$
1 . 0 . 1 \mathrm { ~ C ~ } = \Lambda > B > D
$$

It could be concluded that of the mixtures studied, the $\mathbf { \vec { x } _ { A } } ^ { \mathbf { s } }$ and $\curvearrowleft$ mixtures provided the most intense and total light output. The $a _ { \mathbf { B } } =$ and $\angle D =$ mixturcs generated, significantly, less light in the visible spectrum.

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5. DISCUSSION OI POTENTIAL FIASH BLINDNTSS EFFECTS

Sevcral important questions had to be answcred beforc these data could be interpreted in terms of potential flash blindness effects:

1. What is the level of flash luminosity that will produce permanent eye injury?

2. What is the level of flash luminosity that will produce transient flash blindness?

3. If the measure of the transient flash blindness is expressed in terms of functional requirements calling for viewing and resolution of specific objects, how does the luminosity of the objects to te viewed by the observer affect recovery time from nor-injurious flash blindness?

5.1 PERMANENT EYE DAMAGE

It has been reported that the threshold energy level for permanent eye damage is between 0.2 and 1.6 cals/cm².³-s

Zaret³ expresses the requirements for permanent eye injury in terms of the fraction of the photopigments which are bieached by the light flash. This bleaching process involves the photochemical transformation of 1l-monocis retinene to. trans-retinene. "The 1l-monocis retinene complexes with the opsin enzymes to form the active photosensitive pigments. Upon light excitation the 1l-monocis olefin is transformed to the more chemically stable trans isomer via an electronically or vibrationally excited state.7-9. The trans-retinene, a yellow pigment, which is formed is not compatible with the opsin enzyme and, thus, does not form a photosensitive pigment., Recovery of the bleached pigment is dependert upon a chemical transformation back to the 1l-monocis isomer catalysed by retinene isomerizase.

The concentration of visual pigment only begins to be significantly affected by light intensities of the order of 105 troland-seconds\* and decreases rapidly with further increase in intensity. The concentration of bleached pigment as a function of light intensity can be expressed as follows³

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\*The troland is the unit of rctinal illumination. It is equal to the product of the luminance of the objeçt viewed in candles/(metcr)²and the area of the pupil in mm².

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$c _ { b }$ is the concentration blcachcd at exposure It,

${ \tt c } _ { \tt o }$ is the original pigment concentration,

It is the retinal total irradiance in troland-seconds, and

αγ is the photosensitivity expressed in $( 1 1 d - s e c ) - 2$

In the case of the human pigments the value of a γ is approximately $1 0 ^ { - 7 } ( t 1 - s e c ) ^ { - 1 }$ . Zaret estimates that as the fraction of pigment bleaching approaches unity permanent retinal damage'occurs. Within the time frame of the flashes which were produced in the experiments reported here,the threshold damage irradiances are approximately 0.4 cals $1 0 \pi ^ { 2 } ( 4 \times 1 0 ^ { 9 } + d - s \epsilon c )$ and 1.6 $\mathrm { c u l s } / \mathrm { c } \mathrm { \bar { m } } ^ { 2 } ( 1 . 6 \times 1 0 ^ { 1 0 } \mathrm { t d } - \mathrm { s } \mathrm { \bar { e } C } ) ^ { 1 0 - 1 2 0 }$ for exposures of 1 and 100 msec, respectively. According to Brown, these irradiance levels must be delivercd at flux levels of at least 0.7 cal $s / c m ^ { 2 } - s e c$ or the rate of heat dissipation in the eye tissue will be sufficient to prevent an elevation of temperature to the degree whére thermal burn will occur.

At 5550-angstroms the wavelength of maximum sensitivity to the eye, one watt of radiant energy corresponds to 672.1 lumens. Assuming that all of the light emitted from the pyrotechnic flash devices tested during the program is at this wavelength, the light intensities required to affect thermal damage to the retina would be 1.75 ard $6 . 9 9 \times 1 0 ^ { 4 } 1 0 \mathrm { { m e n } } = 8 0 0 / \mathrm { { f t } } ^ { 2 }$ for exposures of 1 and 100 msec, respectively. The above estimates take into account the fact that the light received at the cornea is-intensified when it arrives'at the retina (i.e., the imags size is reduced): Ham noted that an iradiance received at the cornea of a rabbit eye is intensified by a factor of 60 tímes whèn it reaches the retina.

With respect to the experiments performed in this investigation, these values are considered to be low. Assuming that the light emitted from the flash units have the same spectral characteristics as the sensor, than the luminous efficiency of the light output is only 28 percent that of 5550 angstrom light. The threshold light exposures would then be $6 . 2 6 \times 1 0 ^ { 4 }$ and $2 . 4 8 \times 1 0 ^ { 5 }$ lu $\tt n e n - s e c / f t ^ { 2 }$ for exposures between 1 and 100 msec, respectively.

Based on the luminous intensity data, shown in Table $\tilde { \mathfrak { U } _ { \bullet } }$ it can be seen that the small photoflash chargcs (i.e., the SS and SSDE series) are

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not capablc of delivering damaging light flashes. The larger cliarges (i.c., the S and SD serics) can produce permancnt eye damage. Further discussions rcgarding the possibility of permancnt eye injury are presented clsewhcre in this report (sce Section 5.3.2).

5.2 RECOVERY TIME TO LIGHT FLASHES

Before one can estimate the recovery period after light exposure it is important that the important recovery measurcment conditions be defined. Clearly, the intensity of the light which the obscrver is exposed to will determine recovery time. An additional consideration is the illuminance of the object which the observer needs to detect after exposure for func-. tional reasons.

A review of the literature was made in order to define the.dependence of recovery on the two factors noted above. The results of this search and the subsequent analyses are shown in Figure 10.

5.2.1 Review of Flash Blindness Experiments

Metcalf and $8 0 \pi ^ { \circ } \cdot ^ { 2 \circ }$ conducted flash blindness experiments using the high intensity flashes from a carbon arc. The experiment was designed to determine the effect of light exposures likely to be encountered during nuclear operations. Each of the four subjects had their pupils dilated prior to exposure. A 6mm artificial pupil was used in order to maintäin constant pupil size. The subjects were exposed for 100 msec to illuminà- tion ranging from 70 to 12, 000 lumens per square foot. .Following this exposure, the subjects were required to detect the flashing of a 17 minute visual angle circular patch. The luminance of the test patch was varied between .07 and 71 foot-Lamberts. A summary of a complete set of this data at a flash luminosity·of $5 ^ { \cdot } \times 1 0 ^ { 5 }$ $\sin c \pi - s e c / \tan ^ { 2 }$ is shown in Figure 10.

The time required.to recover visual sensitivity following exposure to high intensity, short duration adapting flashes also has been investiğated by Chisum and Hill.s, 1 Adapting flashes of 33 to $1 6 5 ^ { \circ } 1 5 0 0$ and 9.8 msec in duration with luminances from $1 \times 1 0 ^ { 4 }$ to $5 \times 1 0 ^ { 8 }$ lumens $\sqrt [ 3 ] { t t ^ { 2 } }$ were used. Visual sensitivity was determincd by the resolution of gratings requiring acuities\* of 0.13 and 0.33 at display luminances between approximately ,004 to 200 millilamberts. The 0.33 acuity level requires the function of cones whilc the 0.13 acuity level can be resolved by rod vision. The light pulscs used by Chisum and Hill which best represent the flashes

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\*Acuity is defined as the relative abllity of the visual organ to resolve detail. It is usually expressed as the reciprocal of the minimum angular separation in minutes of two lines just resolvable as separate.

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from the pyrotcchnic devices tested during this program were selected for . the comparisons made in Figure 10. Also the data for the acuity lcvel 0.33 was used, since the effects to cone vision aro the most critical to this study. It should be noted that rocovery from rod saturation is a much faster process than rccovery from cone saturation. The iatter also rcquires more energy for saturation.

It was observed that the recovery timcs for the light illuminations of $5 \times 1 0 ^ { 5 } , 1 4 \div 2 0 \cdots 5 0 0 / E t ^ { 2 }$ , reported by Metcalf and Horn, and $5 \times 1 0 ^ { 4 }$ lumens-$\tt s e c / i t ^ { 2 }$ reported by Chisum and Hill were almost identical. This is not too surprising after one revlews the discussions by Brown and Zaret. Namely, both postulate that the relation between the energy of an adapting flash and recovery time for a specific visual task is similar in nature to that shown·in Figure 11. Y

Figure ll. A hypothetical curve illustrating the relation between energy of a blinding flash and time required for detection of information in a visual display. The minimum detection time at low flash energy corresponds to visual reaction time. Detection time approaches infinity as flash energy approaches a value which will cause irreversible injury.

For very low adapting flash energies\* thore is very little, if any, effect on the visual capability, and recovery time is minimal. As energy is increased, there is an increase in recovery time at an increasing rate. The form of this. function depends on the nature of the visual task: As the energy of the adapting flash reaches a level which corresponds to a maximum possible blcaching of the photosensitive pigments of the retina, the rate of increase of recovery time may be expected to decrease. It is postulated as shown in Figure 1l that recovery time may actually assume a constant value over • some range of adapting flash energies beyond that at which maximum bleaching occurs.

\*Adapting flash energy usvally refers to the total energy to which the subject is cxposed and from which the subjcct must recover normal vision.

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of thc light pulsc. Thcrcforc therc 1s an unccrtainty in the total cxposure duration of cach subjcct to the light. Thcrefore these data wero not used to corrclate results obtaincd.in the prosent study.

5.3 INTERPRETATION OF RESULTS

The measurcd light intensities and durations were introreted in term of possible irreversible and revcrsible eye effects.

5.3.1·Illumination of Photoflash

The experimentally measured illuminance of each pyrotechnic test device as reported in Table Il was estimated as a function of distance from the flash origin using the inverse square law. These estimates are shown in Figures 13 and 14. The expected illuminance which observers would received from exposure to a G.E. No. 50 flash bulb are also shown in these figures. The value for the total output of this flash bulb, 1x 105 lumensec/ft², was obtained from General Electric specifications.

5.3..2 Estimated Eye Effects

Some of the iso-illuminance curves shown in Figure 1l were extrapolated to a display illuminance level of 0.1 millilamberts (or 0.093 lumens/ft2). The recovery time for each of the reported adapting flash energies shown in Figure 1l were estimated for each of four display luminances; 0.1, 0.2, 0.5 and 1.0 millilamberts. These estimates are tabulated in Table III.

TABLE III. ESTIMATED RECOVERY TIMES AS A FUNCTION OF ADAPTING LIGHT ENERGY AND TARGET DISPLAY LUMINANCE

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Thesc cstimates are also indicated by the vertical dashes crussing each of the curves in Figure 1l.

For cach pyrotcchnic dovice tested, the recovery times for a subject exposcd to the light flash were estimatcd using the data in Figures 11, 13, and 14 and Tablc III. These estimatcs were made as a function of distance away from the flash and the luminance levels of objects which the observer might attcmpt to detect after exposure. These estimates are reported in Figures 15 and 16.

As expected the large photoflash devices (i.e:, the S and SDE series) should be the most effective as far as separation distance is concerned. An observer separated from the flash by 50 feet can be affected if an SA charge is employed.. At separation distances less than 7 feet there would be the possibility that irreversihle eye damage could be affected using the SA charge. Significant flash blindness effects are expêcted within this distance range for all of the charges. Recovery times of as long as 60 seconds are prcdicted for the detection of objects which are very dimly illuminated.

The effects of exposure to a G.E. 50 flash bulb were also predicted., It can be seen that the estimated effects are not as great as for the S and SDE series photoflash units. By further comparison with a recent report by Tiller et al.15 (ARPA Contract DAAK02-69-C-0338) the estimates made for the G.E. 50 flash bulb appear to be reasonable. Tiller et al. evaluated the eifects of exposure to this flash bulb to subjects performing military tasks. Thc subjects were exposed to a flash at distances between 6 and 19 feet. After exposure the subjects were required to detect ground emplaced mines or detect and fire upon a test target. All of these tests were performed under various night time concitions to which the subjects had adapted before being exposed to the light flash. It was found that the subjects, all trained Marines, were able to resume their assigned task with the same efficiency after an average reċovery time of 5 to 20 seconds, No indication of reflected luminances of the objects detected were made. It is felt, however, that the predictions of recovery times for dimly lit displays (viz., 0.1 and 0.2 millilamberts) agree with the results obtained by Tiller et al. Between 6 and 10 feet it is predicted that exposure to the G.E. 50 flash should take approximately 8 to 18 seconds. No predictions beyond 10 fcet for the G.E. 50 were made because of lack of data. However thcre is much indication to suggest that at longer distances (i.e., lower flash energies) the recovery times versus distance decreases at a very small rate.

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The estiinated rccovcry times aftcr exposure to the smaller photofash sources are shown in Figure 16. It is not anticipated that eye. damage could be affected by these charges even at short separation distances. Again the "A" and "C" mixturcs are cxpected to be th3 most efficient.

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6. CONCLUSIONS

Sixteen pyrotechnic flash mixtures - fragmenting container combinations were tosted. It was shown that significant flash blindness cffects can be expected to result from the exposure to these flashes, all of which occur within 50 mscc. These effccts can result by exposure to these charges at distances within a range of 50 feet depending on the pyrotechnic mixture and quantity, container design, and method of initiation.

6.1 CARTRIDGE DESIGN

The series S and SDE charges (i.e., the 2.7 in. photoflash cartridge) produced the most intense light and are expected to be effective at distances as far as 50 fect. The external explosive burster attached to the outside of the "S" cartridge was expected to increase the light intensity by compacting the mix before ignition.. However, for the larger cartridge this does not appear to have been successful. For the smaller 0.83 in. photoflash cartridge the expected trend resulted. The effective compaction by this imploding mechanism probably increases with decreasirg cross-sectional area.

6.2 PHOTOFLASH MIXTURE

The type "A" and "C" mixtures in all cases generated the most light output. In some cases the "C" mixture produced light pulses of longer duration as previously anticipated. . The "B" and "D" mixtures were not as effective. In fact the performance of the "D" mixture was relatively poor.

6.3 DATA INTERPRETATIONS

In order to estimate. the flash blindness effects, correlations between reported data had to be made. The results of the analyses appear to be consistent with expectation, namely that recovery time is dependent not only on the flash energy but also on the luminance of objects which are visually sought during the recovery period. Also the relatively insensitive change of recovery time at flash energies which produce 90 to 100 percent pigment bleach was shown in this analysl's.

It is useful to note that the large light sources used in our experiments (i.e., the S and SDE series), produced more intense illumination than the source employed by the Vertex Corporation.Correspondingly, longer incapacitation times are predicted for the S and SDE photoflash units as compared with the G.E. 50 photoflash used in the Vertex studies. In addition, on the basis of our indepcndent experirental data, we could predict the shorter incapacitation times reported by Vertex for their weaker light source.

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REFERENCES

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APPENDIX1

In order to clarify the qucstion of potential applications of bright light sources, a series of simple scenarios have becn developed, which illustrate possible suitable situations.

The use of a detonating pyrotechnic'permits the generation of casing fragmcnts as well as intense light, if the material is enclosed in a metal casing. On the other hand, packing the pyrotechnic into a nonmetallic (e.g., cardboard) casing, essentially eliminates any significant fragment hazard. These two modes of operation find separate regimes of possible application.

I. PERIMETER DEFENSE

Given a situation in which a village or a group of men wish to provide a very distinct indication of an attempt at perimeter penetration, by the enemy, and in addition wish to either inflict temporary optical incapacitation alone, permanent optical incapacitation alone, or fragment damage in addition to the optical incapacitation, these pyrotechnic light sources can play a useful role.

Thus, cased in metal and triggered by sensors (or trip wires)' within the effective fragment range, they provide direct fragment damage capability with a good possibility of severe permanent optical impairment at such relatively short ranges.

Triggered by sensors deployed outside the effective fragment range, the effects would be primarily temporary optical incapacitation and disorientation with a low probability of fragment damage.

In specific situations, calling for no fragmentation effects, such as one in which friendly personnel may inadvertantly trigger the charge, the sensors can be deployed far enough away to assure only temporary optical incapacitation and fragmentation can be completely eliminated with a cardboard casing for the pyrotechnic.

II. VEHICLE PROTECTION AGAINST KIDNAP ATTEMPT

Given the premise that abductors (e.g., of South American diplomatic representatives) do not wish to kill the hostage during the kidnap attempt, a system for providing even 5 - 10 seconds of optical incapacitation in a 360° field around the car in which the hostage is driving, provides an opportunity for escape, while the abductors are optically disoriented. This system would be more 'effective at night than in the daytime. The light source could be either pyrotechnic or electric discharge. It could be made safe against accidental discharge causing permanent damage to innocent bystanders.

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III. TEMPORARY DISRUPTION OP VEIIICLE CONVOY BY CAUSING OPTICAL INCAPACITATION OF LEAD DRIVER

Tho sccnario here is rclatively simplo in that the lcad driver can be optically Incapacitated as lic's rounding a turn, or caused to block the road by his inability to see it for a sufficient time to causç a wreck.

IV. ESCAPE FROM AN ENCLOSURE WITH NO PERMANENT DAMAGE TO OTHERS

In some situations, where thc presence of innocent bystanders, • e.g. women and children prevents the use of more damaging techniques, the use of temporary optical incapacitation is of potential interest.

V. PRELIMINARY TO INDIVIDUAL CAPTURE

Where a single individual is to be captured alive, the use of optical incapacitation may provide useful assistance. Thus, a bright light source generated near him by impact functioning of, a device fired from a shotgun can provide sufficient temporary optical incapacitation to permit other capture techniques to be employed more reliably.

VI. SUMMARY

While these scenarios do not provide a complete list of potential applications, they should be useful in examining the va lue of a system which combines the capability for fragmentation damage, severe permanert optical incapacitation and transient optical incapacitation with.the cholce fairly easy to control.

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III. TEMPORARY DISRUPTION OF VEHICLE CONVOY BY CAUSING OPTICAL INCAPACITATION OF LEAD DRIVER

The sccnario herc is rclatively simplc in that the lead driver can ba optically incapacitated as he's rounding a turn, or caused to block tho road by his inability to see it for a sufficient time to causę a wreck.

IV. ESCAPE FROM AN ENCLOSURE WITH NO PERMANENT DAMAGE TO OTIERS

In some situations, where thc presence of innocent bystanders, . e.g. women and children prevents the use of more damaging techniques, the use of temporary optical incapacitation is of potential interest.

V. PRELIMINARY TO INDIVIDUAL CAPTURE

Where a single individual is to be captured alive, the use of optical incapacitation may provide useful assistance. Thus, a bright light source generated near him by impact functioning of, a device fired from a shotgun can provide sufficient temporary optical incapacitation to permit other capture techniques to be employed more reliably.

VI. SUMMARY

While these scenarios do not provide a complete list of potential applications, they should be useful in examining the value of a system which combines the capability for fragmentation damage, severe permanert optical incapacitation and transient optical incapacitation with.the cholce fairly easy to control.

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