MIL-PRF-A3279602B.pdf

INCH-POUND

MIL-PRF-A3279602B(CR)

17 October 2003

PERFORMANCE SPECIFICATION

IMAGE INTENSIFIER ASSEMBLY,

18MM MICROCHANNEL WAFER NIGHT VISION

MX-10160C/AVS-6

This specification is approved for use by Program Executive Office - Soldier (PEO-SOLDIER), Department of the Army, and is available for use by all Departments and Agencies of the Department of Defense.

1. SCOPE

1.1 Scope . This specification covers the Image Intensifier

Assembly, 18MM Microchannel Wafer, MX-10160C/AVS-6 (see 6.1).

2. APPLICABLE DOCUMENTS

2.1 General . The documents listed in this section are

specified in sections 3 and 4 of this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned that they must meet all specified requirements documents cited in sections 3 and 4 of this specification, whether or not they are listed.

Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Product Manager Sensors and Lasers, ATTN: SFAE-SDR-SSL, 10170 Beach Road, Building 325, Fort Belvoir, VA 22060-5862

AMSC N/A FSC 5855

DISTRIBUTION STATEMENT C. DISTRIBUTION AUTHORIZED TO U.S.

GOVERNMENT AGENCIES AND THEIR CONTRACTORS FOR OFFICIAL USE OR FOR

ADMINISTRATIVE AND OPERATIONAL USE, AS DETERMINED 17 OCTOBER

2003. OTHER REQUESTS FOR THIS DOCUMENT SHALL BE REFERRED TO PM

SENSORS AND LASERS, ATTN: SFAE-SDR-SEN, 10170 BEACH ROAD,

BUILDING 325, FORT BELVOIR, VA 22060-5862.

MIL-PRF-A3279602(CR)

2.2 Government documents .

2.2.1 Specifications, standards, and handbooks . The

following specifications, standards, and handbooks form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those listed in the issue of the Department of Defense Index of Specifications and Standards (DoDISS) and supplement thereto, cited in the solicitation.

SPECIFICATIONS

DEPARTMENT OF DEFENSE

MIL-PRF-A3279454(CR) - Aviator’s Night Vision Imaging System AN/AVS-6(V)3

MIL-PRF-49425(CR) - Aviator’s Night Vision Imaging System AN/AVS-6(V)1A

STANDARDS

MIL-STD-810F - ENVIRONMENTAL ENGINEERING

CONSIDERATIONS AND LABORATORY TESTS

(Copies of specifications and standards required by contractors in connection with specific procurement functions should be obtained from the procuring activity or as directed by the contracting officer.)

2.2.2 Other Government documents, drawings and publica-

tions . The following other Government documents, drawings and publications form a part of this document to the extent specified herein. Unless otherwise specified, the issues are those cited in the solicitation. All military and government specifications/ standards excluding this specification cited in the following documents are for reference only and do not form a part of the requirements therein .

DRAWINGS

A3279602 - Image Intensifier Assembly, Night

Vision, MX-10160C/AVS-6 A3279454 - Aviator’s Night Vision Imaging System

AN/AVS-6(V)3

5009761 - Aviator’s Night Vision Imaging System

AN/AVS-6(V)1A

TECHNICAL MANUAL

TM 11-5855-313-23&P - Aviation Unit and Intermediate Maintenance Manual Including Repair Parts and Special Tools List, AN/AVS-6(V)3

(Copies of drawings and technical manuals required by contractors in connection with specific procurement functions should be obtained from the procuring activity or as directed by the contracting officer.

2.3 Order of precedence . In the event of a conflict

between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.

3. REQUIREMENTS

3.1 Description . The Image Intensifier Assembly, Night

Vision MX-10160C/AVS-6 herein referred to as the assembly, shall employ a Group III-V compound, semi-transparent photocathode sealed to a glass faceplate forming the input window to the assembly. The assembly shall contain an integral phosphor screen placed upon a fiber optic inverter. The assembly shall include an integral power supply and be encapsulated within a hard-surface insulating metallized envelope.

3.2 Certification . Unless otherwise specified by the

contract or purchase order, image intensifier assemblies, furnished under this specification shall be products approved as certified products (see 3.5.22 and 6.3).

3.2.1 Initial production (IPT) When specified in the

contract or purchase order, the supplier shall furnish and test assemblies in accordance with the requirements of 4.2 .

3.2.2 Component certification . After successful comple-

tion of IPT, any change in supplier of the components listed in

3.3.3 shall require re-certification to the extent required by the Government. A change of any component or material used in the manufacture of the assembly which could impact reliability must be verified by re-certification to the extent necessary as determined by the IPPT.

3.3 Construction . The MX-10160C/AVS-6 shall be constructed

in accordance with the contract or purchase order, drawing A3279602, and all the requirements of this specification and other associated drawings which affect interface and/or interchangeability of the MX-10160C/AVS-6 with the ANVIS system.

3.3.1 Weight . The weight of the assembly shall not exceed

85 grams.

3.3.2 Parts and materials . Parts and materials shall be

as specified and as defined by the applicable drawing (see 3.3).

The contractor shall select parts and materials which shall be capable of meeting all of the operational and environmental requirements specified herein. Any change of a part or material after certification requires notification of the procuring activity and submittal of proposed re-certification. Recovered materials shall be used to the maximum extent possible.

3.3.2.1 Phosphor screen . The phosphor screen shall be type

P-43 or equivalent as defined commercially.

3.3.3 Components . The following requirements shall be met

by each assembly delivered without damage (see 3.5.9) nor degradation of performance(see 3.5.30) to the assembly.

3.3.3.1 Power supply . The integral power supply shall meet

all of the operational characteristics when powered by two 1.5 Vdc “AA” alkaline or lithium batteries or an equivalent 2.0 to

3.0 volts direct current (Vdc) power source.

3.3.3.2 Fiber optic inverter . The fiber optic inverter

shall exhibit the following characteristics:

3.3.3.2.1 Shear distortion . Shear distortion (see 3.5.3.1)

shall not exceed 25 micrometers over the display area.

3.3.3.2.2 Gross distortion . Gross distortion (see 3.5.3.2)

shall cause no point on the image of a straight line, through any axis, to be displaced more than ± 30 microns relative to the best-fit straight line (see 3.5.3.3). Displacement measurements shall be rounded to the nearest whole micron. The maximum slope of the straight line image shall be less than 15 microns per millimeter across the line image and less than 25 microns per any two millimeters from the best-fit straight line. Distortion shall be measured along four (4) axes which are 45 degrees apart.

Distortion measurements shall be initiated from an identifiable reference point located on the fiber optic inverter. The line image cannot have more than two slope reversals. Slope reversals less than ± 5 microns shall not be considered as a change in slope.

3.3.3.2.3 Image inversion . The fiber optic inverter shall

rotate a straight line image 180 ± 1 degree in a clockwise direction when viewed from the display side relative to the end points of the best-fit straight line (see 3.5.3.3). Image inversion measurements shall be rounded off to the nearest tenth of a degree.

3.3.3.2.4 Chicken wire . When the fiber optic is uniformly

illuminated and viewed under 10-power magnification perpendicular to the plane surface, the fiber optic shall meet the chicken wire (see 3.5.4) limits specified in Table I.

TABLE I. Fiber optic allowable chicken wire .

Number of allowable incidences

Minimum length

(inches)

Maximum length

(inches) Chicken wire (zone 1) Disregard lengths which are ≤0.003 inches.

>0.003

Chicken wire (zone 2) 9 each spaced ≥ 0.035 inches apart. Disregard lengths which are ≤0.003 inches.

0.030 0.015

>0.003

≥0.030 <0.030 <0.015

Chicken wire (zone 3) Disregard lengths which are ≤0.015 inches.

0.045 0.030

>0.015

≥0.045 <0.045 <0.030

Zone 1 - 0.295 inch diameter circle in center of optic.

Zone 2 - 0.295 to 0.580 inch annulus concentric with Zone 1.

Zone 3 - 0.580 to 0.710 inch annulus concentric with Zone 2.

3.3.3.2.5 Fiber optic inverter surface finish . The output

surface of the fiber optic inverter shall have a minimum of a 60/40 (scratches/digs) finish over the full useful area of tube (see 3.5.18).

3.3.3.3 Microchannel plate .

3.3.3.3.1 Ion barrier film quality . If an ion barrier film

is used, there shall be no more than 10 type-B holes (see 3.5.31) over the total useful area of the output screen. There shall be no holes present having an area greater than a circle with a diameter of 125 micrometers.

3.3.3.4 Input faceplate. The input faceplate shall be of

optical quality Grade A with a minimum of a 60/40 (scratches/digs) finish and flat within 10 fringes using the sodium D light.

3.3.4 Chrome . There shall be no visible chrome present

between the photocathode and the darkened outer annulus of the input faceplate.

3.3.5 System interface . When inserted into a certified

(see 3.5.22) ANVIS binocular assembly, the assembly shall operate and allow the objective lens to be focused from 41cm through infinity, and allow the eyepiece lens to be focused from +2 to -6 diopters. There shall be no flashing, flickering, or intermittent operation of the image intensifier assembly (see 3.5.9).

3.3.6 Identification and marking . Each assembly shall be

marked in accordance with drawing A3279602.

3.3.7 Workmanship . The image intensifier assembly shall

be free from burrs, chips, dirt, or any embedded or surface foreign material. Optical surfaces of the image intensifier shall be free from imperfections that adversely affect the prescribed performance. Optical element surface quality shall be consistent with the best commercial practices.

3.3.8 Interchangeability . The image intensifier assembly

shall be interchangeable (see 3.5.32) between certified ANVIS series of systems from any supplier and shall meet the maintenance philosophy of TM 11-5855-313-23&P.

3.4 Operational performance requirements . Operational

performance requirements shall be verified using test methods reviewed and approved by the procuring activity. Unless otherwise specified herein, operational performance requirements shall be complied with without damage (see 3.5.9) nor degradation of performance (see 3.5.30) and under the following conditions:

a. The radiation source used for evaluation of photocathode sensitivity, EBI, luminance gain, signal-to-noise, output brightness uniformity, and reliability shall be a tungsten filament lamp operated at a color temperature of 2856 ± 50 Kelvin (K).

b. The radiation source used for evaluation of burn-in/ESS, temperature cycling, temperature extremes, environmentals, halo, bright source protection, fixed pattern noise, image alignment, resolution, Modulation Transfer Function (MTF), useful cathode diameter, screen quality, veiling glare, EMI, and luminance persistence shall be a tungsten filament lamp operated at a color temperature of 2700K to 2900K.

c. The photometer used for screen brightness measurements shall be calibrated against a standard source as specified below:

(1) Tungsten filament lamp operated in conjunction with an opal glass or integrating sphere such that the color temperature of the radiation emitted from the opal glass or integrating sphere is 2856 ± 50K.

(2) Opal glass or integrating sphere to produce a uniform, Lambertian distribution.

(3) Corning spectral filters, numbers 3-71 and 4-67, or equivalent.

(4) Output brightness of 0.1 to 1.0 footlamberts (fL) uniformly distributed over the output aperture.

d. The actual values of input illumination or radiation employed in operational performance tests shall be within + 25% of that specified. These actual values shall be used in all computations used to determine compliance with the performance requirements.

e. Meters used for monitoring lamp current and voltage shall have an accuracy of ± 0.25 percent.

f. Tests unless otherwise specified shall be performed at room temperature (see 3.5.7).

g. Neutral density filters used in test equipment shall have transmission characteristics within 10 percent of the nominal filter transmission from 0.35 to 1.0 micrometer.

h. Input voltage on the assembly shall be 3.0 ± 0.05 Vdc.

i. All gain and environmental tests except humidity shall be performed in a grounded housing.

j. Environmental test chambers shall maintain the temper-ature within ± 2°C of the specified test temperature.

k. All measurements of time shall be with a calibrated device capable of indicating a time variation no larger than one-half of the least significant figure of the requirement (i.e., requirement 2 seconds, indicator ≤ 0.5 second; requirement 2.0 seconds, indicator ≤ 0.05 second) and be calibrated to ±0.10 of the least significant figure of the requirement.

3.4.1 Photocathode sensitivity . Over a 16mm useful

diameter circle with 0.001 lumen of radiation, the luminous transmission sensitivity shall be not less than 2,200 micro-amperes per lumen (µA/lm). The value of photocathode sensitivity utilized to determine this specification compliance shall be measured at an applied voltage that is not more than 50Vdc higher than that actually utilized in the given tube assembly. Over a 16mm useful diameter circle with filtered radiation between 1 x 10 -8 to 5 x 10 -6 watt, the radiant sensitivity shall be not less than 240 milliamperes/watt at 0.830 ± 0.001 micrometer and 120 milliamperes/watt at 0.880, ± 0.001 micrometer. The value of radiant sensitivity utilized to determine this specification compliance shall be measured at an applied voltage that is not more than 50Vdc higher than that actually utilized in the given tube assembly.

3.4.2 Equivalent background input (EBI) . The equivalent

background input at room temperature shall not exceed 2.5 x 10 -11 phot (lumens/square centimeter) when tested at room temperature.

3.4.3 Luminance gain . The assembly shall exhibit at room

temperature luminance gain and high light level saturation characteristics per Table II and Figure 1 (see 3.5.7 and 3.5.28).

TABLE II. Saturation requirements for luminance gain .

Nominal light input (fc) allowable Gain output

(fL)

Maximum gain

Maximum output (fL)

Maximum allowable input current

(mA)

2 x 10 -6 2 x 10 -4

1.0 20.0

50,000 12,500

NA

2.5 2.5

80,000 21,000

4.2 4.2

3.4.4 Halo . The halo (see 3.5.8) produced by projecting

light through an aperture and the AN/AVS-6 objective lens, or equivalent, onto the input of the assembly, such that a 0.350 ± 0.02mm diameter spot is produced on the photocathode, shall be no greater than 0.70mm in diameter. The illumination in the spot shall be not less that 5 x 10 -4 footcandle (fc). The illumina-tion incident on the photocathode in the region outside the 0.350mm spot shall not exceed 5 x 10 -7 fc. The variation between the largest halo and the smallest halo anywhere in the useful area shall be no greater 0.15mm.

3.4.5 Bright source protection . With operating potential

applied, the assembly shall not be damaged (see 3.5.9) when subjected to an input illumination of not less than 50 milli-lumens concentrated on the photocathode within an area no greater than one square millimeter for a time interval not less than 60 seconds. There shall be no discernible damage (see 3.5.9) after a non-operating period of not more than 24 hours.

3.4.6 Signal-to-noise ratio . The signal-to-noise (S/N)

ratio (see 3.5.29) shall be a minimum of 28.0.

3.4.7 Fixed pattern noise .

3.4.7.1 Multi-to-multi pattern variation . With the

operating potential applied to the assembly and the entire photocathode uniformly illuminated at a level of 1 to 2 x 10 -4 fc, multi-to-multi brightness deviations from the mean value shall not exceed ± 10 percent.

3.4.7.2 Multi-boundary pattern noise . With the operating

potential applied to the assembly and the entire photocathode uniformly illuminated at a level of 1 to 2 x 10 -4 fc, the average value of the brightness deviations of the multi-boundary intensities shall not deviate from the mean value of the adjacent multi intensities by more than ± 10 percent. The mean value shall be established from the three adjacent multies containing the above multi-boundaries.

3.4.8 Output brightness uniformity . When the photocathode

is uniformly illuminated with between 5 x 10 -6 and 1 x 10 -5 fc of light, the output brightness uniformity shall be such that the ratio of the maximum to minimum brightness variation over the useful screen area shall not exceed 3:1. For input illumination of 1 to 3 x 10 -10 watt of radiation of wavelength 0.830 ± 0.001 micrometer, the ratio shall not exceed 3:1. Under the same conditions, when the screen is viewed with a 10-power magnifier, the background shading shall be uniformly graded with no distinct lines of demarcation between the light and dark areas.

3.4.9 Image alignment . With the operating potential

applied and the photocathode illuminated to provide best contrast, a test reticle projected on the photocathode of the assembly concentric with the optical axis shall produce an image on the screen of the assembly such that the center of the reticle's image shall fall within a circle 0.006 inch in diameter concentric with the optical axis of the assembly.

3.4.10 Resolution .

3.4.10.1 Center resolution . The limiting resolution (see

3.5.16) of the assembly at the optical axis (see 3.5.15), refer-enced to the photocathode, shall not be less than 64 line pairs per millimeter (lp/mm).

3.4.10.2 Peripheral resolution . The limiting resolution

(see 3.5.16) of the assembly at points along a 14mm diameter circle concentric with the optical axis (see 3.5.15), referenced to the photocathode, shall not be less than 57 lp/mm.

3.4.10.3 Bright light level center resolution . With the

entire photocathode of the assembly illuminated with not less than 20 fc, the minimum center resolution shall be 45 lp/mm.

3.4.11 Modulation transfer function . With an input

illumination of not greater than 8 x l0 -4 fc, the minimum assembly MTF (see 3.5.12) shall be as follows:

a. MTF at 2.5 lp/mm, not required, information only

b. MTF at 7.5 lp/mm, not required, information only

c. 61 percent MTF at 15.0 lp/mm

d. 38 percent MTF at 25.0 lp/mm

3.4.12 Useful cathode diameter . The useful cathode dia-

meter shall be not less than 17.5mm.

3.4.13 Screen quality .

3.4.13.1 Bright spots . With no light input to the assembly, observe and locate bright spots or discernible field emissions (see 3.5.13) on the screen when viewed with a 10-power magnifier.

With 2 x 10 -6 fc incident on the photocathode, there shall be no bright spots or discernible field emissions (see 3.5.13) brighter or larger than the background scintillations (see 3.5.14) on the screen when viewed with a 10-power magnifier. With the radiation level on the photocathode adjusted to obtain the best contrast, there shall be no bright spots visible on the screen when viewed with a 10-power magnifier.

3.4.13.2 Dark spots . The dark spots which exceed a contrast

(see 3.5.21) of 30 percent of their surrounding areas shall not exceed the sizes and quantities specified in Table III. If the spot is non-circular, the diameter of the circular spot of an equal area shall be used. When the distance between one or more spots and a given spot is less than the maximum dimension of the given spot, all the above spots shall be considered as one circular spot whose area is equal to that of the smallest rectangle or circle (whichever has least area) which encompasses the above spots and the separation between them. Graininess caused by grainy or "peppery" phosphor screen, channel-to-channel gain variations, or photocathode irregularities (see 3.5.19) shall not be discernible over the useful diameter to the degree that it detracts from normal operation, when viewed with a 10-power magnifier and with the photocathode uniformly illuminated.

TABLE III. Tube assembly dark spots .

Size of spots (inches)

Number of spots within 0.22 inch diameter circle

Number of spots within annulus bounded by 2 circles 0.22 and 0.58 inch diameter

Number of spots within annulus bounded by circles 0.58 inch diameter and total screen diameter

0.009 or larger 0 0 0

0.006 to 0.009 0 0 1

0.003 to 0.006 0 0 2

NOTES:

1) The 0.22 and 0.58 inch circles on the image screen shall be concentric with the optical axis of the assembly.

3.4.14 Luminance persistence . When an illumination of 4 x

10 -3 fc is gated OFF, output brightness of the assembly shall fall to not greater than 0.15 percent within 0.30 second.

3.4.15 Off-axis veiling glare . The MX-10160C Image

Intensifier Assembly, when properly incorporated within a certified AN/AVS-6(V)3 system, shall comply with the veiling glare requirements as specified in MIL-PRF-A3279454(CR).

3.4.16 Environmental characteristics . When the assembly is

incorporated into the AN/AVS-6, it shall not cause the system to fail the environmental requirements of MIL-PRF-A3279454(CR) and MIL-PRF-49425(CR). The assembly shall not be damaged (see 3.5.9) nor suffer degradation of performance (see 3.5.30) and shall meet the performance requirements specified herein when subjected to the following environmental conditions. MIL-STD-810F shall be used in developing environmental test methods.

3.4.16.1 Environmental stress screening (ESS) . Each

assembly shall be subjected to an appropriate ESS for the purpose of reduction and elimination of workmanship/infant mortality type failures (see 3.5.9).

3.4.16.2 Vibration . The assembly, with no operating

voltage applied, shall not be damaged (see 3.5.9) nor suffer degradation of performance (see 3.5.30) after being or when subjected to resonance search (see 3.5.20), resonance dwell, and cycling with vibrations of the frequency and amplitude represented in Figure 2 applied both parallel to and perpendicular to the optical axis of the assembly for not less than one (1) hour in each axis.

3.4.16.3 Shock . With no radiation incident on the photo-

cathode, the operating assembly shall not be damaged (see 3.5.9) nor suffer degradation of performance (see 3.5.30) when subjected to 6 shock impacts parallel to the optical axis and 6 shock impacts perpendicular to the optical axis with no more than 2 flashes in each axis. Impacts shall be half-sine wave with a minimum peak amplitude of 75gs (see 3.5.5) and a duration of 6 ± 2 milliseconds measured at the 10 percent amplitude points.

3.4.16.4 Temperature extremes . The assembly shall meet the

requirements specified in 3.4.16.4.1 and shall not be damaged (see 3.5.9) nor suffer degradation of performance (see 3.5.30) by continuous operation from +52°C to –40 °C or after storage from +85°C to -54 °C. The assembly shall not be damaged nor suffer degradation of performance by sudden temperature changes from +85°C to +23°C; +23°C to -40 °C; and -54 °C to +23°C each transition occurring within five (5) minutes. Room temperature pre-test and room temperature post-test values shall be taken.

Soak time at each temperature extreme shall be sufficient to attain temperature stabilization.

3.4.16.4.1 Operating requirements for +52 °C and -40 °C.

a. Input current – not greater than 57 mA at +52 °C and 46 mA at -40 °C.

b. Gain at 2 x 10 -6 fc – between 25,000 and 110,000 at both temperatures.

c. Gain at 2 x 10 -4 fc – not less than 14,000 and not greater than 24,000 at both temperatures.

d. Operational stability at > 1 fL tube output:

(1) The output brightness shall not fluctuate more than ± 10 percent from a steady-state condition and shall not drift more than ± 15 percent from a steady-state condition for a period of 2 minutes after an initial operating time of 2 seconds. All fluctuations shall be random after the initial 2 seconds. There shall be no flickering, flashing, or blinking visible to the naked eye.

(2) Rise time (see 3.5.6) shall not be greater than 7 seconds and overshoot (see 3.5.17) shall not be greater than 40 percent of steady-state output brightness.

e. Gain and EBI. The variation between the room temperature pre-test gain and the room temperature post-test gain shall not be greater than ± 20 percent. Post-test EBI shall be as specified in 3.4.2.

3.4.16.5 Humidity . The unprotected assembly shall not be

damaged (see 3.5.9) nor suffer degradation of performance (see 3.5.30) after subjected to not less than 90 percent relative humidity and varying temperatures from +21 °C to +65 °C for a period of 240 hours. The gain and input current shall not vary more than ± 20 percent, EBI shall not exceed 2.5x10 -11 lm/cm 2, and all parameters must remain within specified limits. After completion of the humidity test, each assembly may be baked at not less than 55 °C and 400mm Hg maximum for not less than 24 hours.

3.4.17 Electromagnetic interference (EMI) . The assembly, when properly incorporated within a certified AN/AVS-6 system shall comply with the EMI requirements as specified in MIL-PRF- A3279454(CR) or MIL-PRF-49425.

3.4.18 Reliability . The assembly shall have a minimum mean

time to failure of not less than 12,500 hours (2,500 hours accelerated). The reliability test sample size and number of failures allowed shall be as specified in the Government approved Quality Validation Plan. Following and during reliability testing, the assembly shall not exhibit damage (see 3.5.9) and shall comply with the requirements specified in Table IV.

Failures of the power supply shall be considered relevant.

TABLE IV. Reliability acceptance levels .

Requirement Acceptance level Luminance gain at 2 x 10 -6 fc 35,000 to 95,000 EBI 2.5 x 10 -11 phot maximum Signal-to-noise 23 minimum Center resolution 64 lp/mm minimum Bright-light level center resolution 36 lp/mm minimum Useful cathode diameter 17.5 mm minimum Output brightness uniformity Per 3.4.8 Screen quality Per 3.4.13

3.4.19 Storage life . The assembly shall exhibit neither

damage (see 3.5.9) nor degradation of performance (see 3.5.30) after exposure to 12 continuous temperature cycles of +85°C to - 54°C followed by either a storage period of not less than 60 days at room temperature (see 3.5.7) or reliability testing (see 3.4.18). During cycling, the assembly shall remain at each temperature extreme until the assembly is thermally stabilized (2 hours minimum), and the chamber temperature rate of change shall be not less than 3°C per minute during transitions. As a minimum, conformance to the luminance gain, input current, signal-to-noise ratio, output brightness uniformity, screen quality, and useful cathode diameter requirements shall be verified upon completion of the 60 day storage period or reliability test.

3.4.20 Room temperature turn-on/operational stability .

a. When the tube assembly is turned on after a non-operational period of not less than 10 minutes, it shall reach 90% or more of its steady-state output brightness within 1.0 second, for each of the following input illuminations: 2 x 10 -6 fc, 2 x 10 -4 fc, and 1.0 fc. Overshoot shall be no more than 40% of its steady-state output brightness. The tube assembly’s output brightness shall not drift more than + 15% from the steady-state condition for a period of two (2) minutes after turn-on.

b. Upon switching to an input illumination between 1 x 10 -6 fc and 1 x 10 -5 fc immediately after exposure to an input illumination not less than 0.2 fc for not less than 3 seconds, the tube assembly shall reach 90% or more of its steady-state output brightness within 1.0 second. Overshoot shall be no more than 40% of its steady-state output brightness. The tube assembly’s output brightness shall not drift more than + 15% from the steady-state condition for a period of two (2) minutes after the switch to the lower input illumination.

3.5 Technical interpretations . The following technical

interpretations shall be, when referenced in sections 3 or 4, mandatory for this specification.

3.5.1 Photocathode . The glass input window with a gallium

arsenide substrate bonded to it is referred to as the photo-cathode.

3.5.2 Phosphor . The phosphor shall be type P-43 or

equivalent as defined commercially.

3.5.3 Distortion . The two types of distortion that are

important in imaging fiber optics are shear distortion and gross distortion.

3.5.3.1 Shear distortion . Causes the image of a straight

line to have a discrete, localized lateral displacement (break).

Shear distortion is due to localized misalignment errors in the assembly of fibers or multifibers. Shear distortion in fiber bundles is sometimes referred to as incoherences.

3.5.3.2 Gross distortion . Causes the image of a straight

line to curve. Gross distortion is caused by a long-range deformation of the flow of fibers during fabrication.

3.5.3.3 Best-fit straight line . A straight line intersecting the +8 and -8 millimeter points of the input straight line image.

The +8 and -8 millimeter measurements are relative to the projected pattern center point.

3.5.4 Chicken wire . Defined as a predominant pattern of

dead fibers which has a width not greater than 0.0005 inches (2 single fibers) whose light transmission is so degraded that with light projected through the optic, single fibers in the area in question cannot be distinguished or identified as single fibers with the use of 50-power magnification.

3.5.5 "g" . A “g” is defined as the nominal acceleration due to gravity at the earth’s surface (i.e., 32.2 ft/sec 2 or 9.81 m/sec 2).

3.5.6 Rise time and decay time . The rise time required for

the assembly to achieve 50 percent of its steady-state perfor-mance after the voltage source is applied to the assembly. The decay time is the time required for the assembly to achieve the screen brightness not greater than 1 x 10 -3 fL after the voltage source is disconnected.

3.5.7 Room temperature . Room temperature is defined as

+23°C +10/-2°C.

3.5.8 Halo . Halo is defined as a circular area of bright-

ness evidenced on the assembly output imaging screen occurring as a result of a small bright source input and concentric with the input. Unless otherwise specified, halo shall refer to the bright circular area associated with the photocathode-to-MCP proximity spacing.

3.5.9 Damage . Damage is defined as:

a. Electrical failure or malfunctioning, intermittent or continuous, including arcing, corona, flashing, flickering, or blinking, or a change in input current greater than ± 20 percent during or subsequent to completion of ESS testing and during the humidity testing.

b. Cracks, breakage, deformation, burrs , corrosion, or deterioration of any part or finish, and missing or loose components.

c. Imperfections in or on optical components that adversely affect optical performance.

3.5.10 Multi-to-multi pattern variation . Discernible

spatial gain variation between individual multi-patterns or groups of multi-patterns.

3.5.11 Multi-boundary pattern noise . Discernible spatial

gain variation between peripheral and interior channels or groups of channels in a multi-pattern.

3.5.12 Modulation transfer function (MTF) . Modulation

transfer function is a measure of the degradation of an image as it appears at the output screen of the assembly as correlated to the input pattern which is normalized to 100 percent contrast at a spatial frequency equal to or less than 0.2 lines per millimeter.

3.5.13 Field emission . Discernible field emission is

voltage-dependent extraneous emission which appears as bright spots or a pattern that may flicker or appear intermittently on the image screen in one general area. Field emission is voltage dependent and is best observed with a low level of radiation incident on the photocathode.

3.5.14 Scintillations . Bright spots which occur on the

image screen randomly in space and time.

3.5.15 Optical axis . The optical axis of the assembly is

defined as the mean centerline of that cylindrical portion of the assembly used to align the assembly in the system housing.

3.5.16 Limiting resolution . Limiting resolution is defined

as the smallest resolution pattern for which the observer can distinguish three black lines and the clear areas between the black lines, for both the vertical and horizontal test patterns.

3.5.17 Overshoot . The percent amplitude of output bright-

ness above a steady-state condition at turn-on.

3.5.18 Useful area . The useful photocathode and phosphor

screen area shall comprise a circle of diameter not less than

17.5 millimeters centered on the assembly optical axis.

3.5.19 Photocathode irregularities . Imperfections in the

photocathode which lead to significantly degraded image quality.

A photocathode grown on a host crystal cut more than 0.5 degree off the proper crystallographic axis, which leads to a terraced crystal surface; and hillocks or craters due to foreign inclusions in the crystal growth.

3.5.20 Resonant frequency . A resonant frequency is defined

as any frequency where the response amplitude is greater than or equal to two times the input vibration amplitude at that frequency.

3.5.21 Contrast . Contrast is defined as B1 Max - B2 Min .

B1 Max + B2 Min

B1 is the brightness surrounding the dark spot.

B2 is the brightness of the dark spot.

3.5.22 Certified product . A product that has successfully

met all requirements of a first article witnessed by the Product Manager Sensors and Lasers or its designated representative.

Should the supplier make substantial changes in the process, materials or personnel used to produce the certified product or have not delivered the certified product to the Federal Government within 12 months of contract award, an Initial Product Testing (IPT) shall be performed to the extent necessary to verify continued compliance to specification requirements for all characteristics of the product affected by the changes.

3.5.23 Veiling glare . Veiling glare shall be defined as

ghost images, crescents or other geometrically shaped images appearing in the system’s FOV, when a bright point source is outside the FOV and illuminating the entrance pupil of the objective lens.

3.5.24 Dirty window . A cosmetic defect in the gallium

arsenide photocathode that reduces or impairs the image definition of the tube assembly.

3.5.25 Luminance transmission sensitivity . The photo

current (in microamperes), corrected for leakage and dark current, divided by the actual input (in lumens).

3.5.26 Radiant sensitivity . The photocathode current (in

milliamperes), corrected for leakage and dark current, divided by the actual input radiation (in watts).

3.5.27 EBI . EBI is defined as [R1/(R 2-R 1) ] x actual input illumination where R1 is defined as the stabilized screen brightness (in fL) with no radiation incident on the photocathode and R2 is the screen brightness (in fL) when the photocathode is illuminated by 3.5 to 7 x 10 -11 phot (lumens/square cm) uniformly distributed over the full useful diameter centered on the photocathode faceplate. The angle of incident flux shall not be greater than 2 degrees from perpendicular such that the acceptance angle covers the full useful area.

EBI may also be determined as follows: With the operating potential applied to the intensifier and no radiation incident on the photocathode, hold for a stabilizing period of not less than one (1) minute and no more than fifteen (15) minutes. At the end of the stabilizing period, with no radiation incident on the photocathode, measure the screen brightness (footlamberts) with the photometer. Divide this reading by the luminance gain measured in paragraph 3.5.28 and multiply by 1.076 x 10 -3 .

3.5.28 Luminance gain . When the photocathode of the opera-

tional tube assembly is illuminated with input light uniformly distributed over the full useful diameter of the faceplate, the luminance gain is defined as the screen luminance (in fL) divided by the actual input illumination (in fc) where screen luminance is measured such that the acceptance angle (of the measuring instrument) subtends a minimum 16mm diameter area centered on the phosphor screen. The screen luminance value utilized in this computation shall be corrected by the background (i.e., no input) luminance value.

3.5.29 Signal-to-noise . Signal-to-noise is a measure of

the image intensifier tube’s average output brightness (signal) divided by the standard deviation of output brightness (noise) per the following equation:

S/N = (S 0 - S bkd)/K(N 0

2 - N bkd

2) 0.5 where, S = dc signal N = rms noise S 0 = average signal output from the S/N test set S bkd = average background signal from S/N test set with light input off N 0 = noise output from S/N test set rms meter N bkd = background noise from S/N test set rms meter with light input off K = correlation factor to obtain a S/N ratio over an equivalent bandwidth of 10 Hz independent of assembly’s phosphor temporal response. K = 1.15 for a P-43 phosphor

These statistics are measured with a specified input spot of light of 0.2 millimeter diameter placed within a 1 millimeter radius from the assembly optical axis, and at a light level of 1 x 10 -5 fc of 2856 ± 50K black body irradiance. The standard deviation of brightness is measured over a 10 Hertz noise equivalent bandwidth.

3.5.30 Degradation of performance . Degradation of

performance is defined as a cumulative change in measurable characteristics which can result in failure of the assembly to meet specified requirements.

3.5.31 Type-B hole defect . A type-B hole is a hole in the

ion barrier film which exists over a series of channels, and has an area equal to a circle with a diameter not greater than 125 micrometers. A type-B hole is manifested as a bright spot on the output screen when the photocathode of a packaged tube is illuminated with not less than 1 x 10 -1 fc.

3.5.32 Interchangeable . An item which possesses such

functional and physical characteristics as to be equivalent in performance, reliability, and maintainability, to another item of similar or identical purposes; and is capable of being exchanged for the other item without selection for fit or performance, and without alteration of the items themselves or of adjoining items, except for adjustment.

4. VERIFICATION

4.1 Classification of inspections . The inspection

requirements specified herein are classified as follows:

a. Initial production testing (IPT) (see 4.2).

b. Conformance inspection (CI) (see 4.3).

4.2 Initial production testing (IPT) . Unless otherwise

specified in the contract or purchase order, the IPT shall be performed by the contractor. The IPT shall consist of the inspections/tests as specified in the Government approved Quality Validation Plan. Disposition of IPT samples shall be as specified in the contract or purchase order (see 6.2.d).

4.3 Conformance inspection . Unless otherwise

specified in the contract or purchase order, the requirements for conformance inspection shall be as specified in the Government approved Quality Validation Plan. Contractors are encouraged to propose commercial like, innovative and/or streamline test methods and procedures which balance government quality conformance requirements, optimize resource considerations, and are of sufficient details to enable the government to evaluate them and make risk assessments as to their adequacy in meeting the specification requirements.

5. PACKAGING

5.1 Packaging . For acquisition purposes, the packaging

requirements shall be as specified in the contract or purchase order. When actual packaging of materiel is to be performed by DoD personnel, these personnel need to contact the responsible packaging activity to ascertain requisite packaging requirements.

Packaging requirements are maintained by the Inventory Control Point’s packaging activity within the Military Department or Defense Agency, or within the Military Department’s System Command. Packaging data retrieval is available from the managing Military Department’s or Defense Agency’s automated packaging files, CD-ROM products, or by contacting the responsible packaging activity.

6. NOTES

(This section contains information of a general or explana-tory nature that may be helpful, but is not mandatory).

6.1 Intended use . The assembly is intended for use in the

AN/AVS-6 V(3) series of Aviator’s Night Vision Imaging System (ANVIS), an electro-optical viewing device capable of intensifying low light levels such that a visible image is presented for viewing and flying purposes.

6.2 Acquisition requirements . Acquisition documents should

specify the following:

a. Title, number and date of the specification.

b. Issue of DoDISS to be cited in the solicitation.

c. Packaging requirements (see 5.1).

d. Schedule for IPT for all line items and disposition of IPT samples less reliability samples.

e. Requirements for conformance inspection.

6.3 Certification . With respect to products requiring

certification , unless otherwise specified by the contract or purchase order, if a product is not certified at time of award, the contract shall require certification prior to first delivery.

The activity responsible for approving certified products is the Product Manager Sensors and Lasers, ATTN: Manager, Product Assurance and Test, 10221 Burbeck Road, Fort Belvoir, VA 22060- 5806. Information pertaining to certification of products may be obtained from that activity.

6.4 Subject term (key word) listing .

ANVIS

Image Intensifier Tube

Custodian: Preparing Activity:

Army - CR Army - CR

Gain/Saturation Requirement

0.01

0.10

1.00

10.00

1.E-06 1.E-05 1.E-04 1.E-03 1.E-02 1.E-01

Photocathode Illumination (footcandles)

S cr ee n

B ri g h tn es s (f o o tl am b er ts

Lower Limit Upper Limit

4.2 FL

80K Gain

50K Gain

2.5 FL

FIGURE 1. Gain/saturation requirement .

2g0.51

0.091 10-1

10-2

10-3

10-4

10-5

10-6

5 14 3352 2000

10 100 1000 10,000

FREQUENCY (Hz)

FIGURE 2. Vibration profile.

D

IS

P L

A C

E M

E N

T

C E

N T

IM

E

T E

R S

-D O

U B

L E

A M

P L

IT

U

D E

) 5g

STANDARDIZATION DOCUMENT IMPROVEMENT PROPOSAL

INSTRUCTIONS

1. The preparing activity must complete blocks 1, 2, 3, and 8. In block 1, both the document number and revision letter should be given.

2. The submitter of this form must complete blocks 4, 5, 6, and 7.

3. The preparing activity must provide a reply within 30 days from receipt of the form.

NOTE: This form may not be used to request copies of documents, nor to request waivers, or clarification of requirements on current contracts. Comments submitted on this form do not constitute or imply authorization to waive any portion of the referenced document(s) or to amend contractual requirements.

I RECOMMEND A CHANGE:

1. DOCUMENT NUMBER

MIL-PRF-A3279602B (CR)

2. DOCUMENT DATE (YYMMDD)

031017

3. DOCUMENT TITLE

Performance Specification for the Image Intensifier Assembly,18mm Microchannel Wafer Night Vision

MX-10160C/AVS-6

4. NATURE OF CHANGE (Identify paragraph number and include proposed rewrite, if possible. Attach extra sheets as needed.)

5. REASON FOR RECOMMENDATION

6. SUBMITTER

a. NAME (Last, First, Middle Initial)

b. ORGANIZATION

c. ADDRESS (Include Zip Code) d. TELEPHONE (Include Area Code)

(1) Commercial

(2) DSN (if applicable)

7. DATE SUBMITTED

(YYMMDD)

8. PREPARING ACTIVITY

a. NAME

Product Manager Sensors and Lasers

b. TELEPHONE (Include Area Code)

(1) Commercial (2) DSN

(703) 704-1346 654-1346

c. ADDRESS (Include Zip Code)

10170 Beach Road, Building 325

ATTN: SFAE-SDR-SEN

Fort Belvoir, VA 22060-5862

IF YOU DO NOT RECEIVE A REPLY WITHIN 45 DAYS,

CONTACT:

Defense Quality and Standardization Office 5203 Leesburg Pike, Suite 1403, Falls Church, VA 22041-3466

Telephone (703) 756-2340 DSN 289-2340

Replica of DD Form 1426, OCT 89