Image Intensifier User Guide
Contents
1. LNS20 Q 25 Q 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 nm Page 7 LEN Understanding Microchannel Plates A Microchannel Plate MCP is an electron multiplier that consists of a thin typically 0 5 mm glass plate through which run a very large number of parallel tubular channels typically 3 10 um diameter A 25 mm diameter MCP contains approximately 1 5 million of these channels also known as pores which are set at a small bias angle to the major axis of the MCP to increase the chances of electrons colliding with the channel walls Electrons entering a channel in the MCP collide with the channel wall and produce secondary electrons These electrons are accelerated through the channel by means of the high potential gradient applied to the MCP and by further collisions with the channel wall produce additional secondary electrons at each collision The result of these repeated collisions is an avalanche of electrons giving an output electron gain of around 10 for a typical single MCP at an applied operating potential of 800 V MCP Pore sizes The table below shows typical MCPs used in Photek detectors Smaller pore MCPs are capable of resolving greater detail Pore Diameter Detector Active Diameter Pitch um 3 2 4 2 x E e 8 Ke 1002 ee 25 88 TE da da MCP Thickness The thickness of a MCP is defined by the pore length to diameter l d ratio and is typically in the2. E E A ecineas ieee evecne sees sa encase 14 Phosphor Screen and Output WindoW iii 14 Conmeen Dagr nC 15 PH TEK liluminaton Ives 18 Single MCP Intensi iers skonsan a ai 18 Multi MCP High Gain Photon Counting Intensiflers eese 18 Coupling to other devil ES ois aa ana 19 Glossary of COINS auuscseee suisse ovp dava eu ao I2 ESTE 2g SEX FS Se SUN ME a 19 Contrast Transfer Function CTF cessisse nnn nnne 19 Equivalent Background Illumination EBI sese 19 First Generation Tubes m 20 CANT PR E EE 20 Limiting ResolUtion iii 20 EUMINESCENESCIRENS onlus 20 WIEN 21 Modulation Transfer Function MTF sessi 21 POLO GOO Ce LT E 21 PAO EOC ICC ING c aaa alia 21 O ONO aaa 21 Quantam EIIcleney TTE nanna 21 Foam Bel ok 211a V e ENE HU 22 HOSOIU ONP O a 22 DCCONG Generation TICS aaa 22 PETAR e PON MR Tm 22 VO 22 Page 2 PH TEK Health and Safety Advice High voltage devices can be hazardous if they are not installed operated and maintained correctly or if a device is damaged Photek cannot accept responsibility for damage or injury resulting from the use of Photek devices Equipment manufacturers and users should ensure appropriate precautions are taken Warni
3. gt MCP Output Black White MCP Output 0V Phosphor Screen Yellow Yellow Yellow phosphor Screen Gain Adjust To Green Monitor ITO Wire should be connected to MCP Input and Ground Page 15 Configuration 6 This configuration shows how a multi MCP intensifier is wired directly to a FP630 power supply The ITO connection if required is connected internally Configuration 7 This configuration shows how a standard wired single MCP intensifier is connected to a FP610 power supply The cathode wire is fitted with a coax cable and terminated with a SMA connector This then connects to the gate unit Configuration 8 This configuration shows how a single MCP intensifier is wired directly to a FP610 power supply The ITO connection if required is connected internally The cathode wire is fitted with a coax cable and terminated with a SMA connector This then connects to the gate unit Configuration 9 This configuration shows how multi MCP intensifier is wired directly to a FP630 power supply The ITO connection if required is connected internally The cathode wire is fitted with a coax cable and terminated with a SMA connector This then connects to the gate unit Configuration 10 This configuration shows how a standard wired multi MCP intensifier is connected to a FP630 power supply The cathode wire is fitted with a coax cable and terminated with a SMA connector This then connects to the gate unit
4. PH TEK ENVISAGE THE F MCP2xx or MCP3xx Image Intensifier FP632 Power Suppl Cathode Blue Blue cathode MCP Input Red Black MCP Input MCP Output Black White MCP Output Phosphor Screen Yellow Yellow phosphor Screen Gain Adjust Monitor Internal ITO Connection if required Gate Unit 5V or 12V smel Co axial Gate Output MCP1xx Image Intensifier Cathode Co axial FP610 Power Supply MCP Input Red Black MCP Input Mod portici lYelow Yellow ai iust Orange Phosphor Screen Yellow Yellow Phosphor Screen Gain Adjust Monitor Violet ITO ITO Wire should be connected to MCP Input and Ground Gate Unit 5V or 12V smal Gate Output Co axial Trigger MCP1xx Image Intensifier Cathode Co axial FP610 Power Supply MCP Input Red Black MCP Input ROAD Ms Phosphor Screen Yellow Yellow Phosphor Screen Gain Adjust Orange Monitor Violet Internal ITO Connection if required Gate Unit 5V or 12V fma CO axial Gate Output Co axial MCP2xx or MCP3xx Image Intengifier Co axial FP630 Power Supply MCP Input Red Black mcp Input MCP Output Black White MCP Output Phosphor Screen Yellow Yellow Phosphor Screen Gain Adjust Monitor Violet Internal ITO connection if required Gate Unit 5V or 12V jjj Coaxial Gate Output MCP2xx or MCP3xx Image Intensifier FP630 Power Supply MCP Output Black White MCP Output Yellow Yellow Cathode Co a
5. 0 3P 300 GM300 8U 300 5 13 8 35 Adjustable transition time When considering the table above it should be noted that the limiting factor of gating performance will almost certainly be defined by the RC time constant of the image intensifier The GM300 3P and 3N are complimentary units one being designed just for short on windows 3N while the other is only used for short off windows 3P The GM10 50B and the GM300 8U can be used in either configuration Phosphor Screen and Output Window The electron image emerging from the MCP output is accelerated into a layer of phosphor deposited on the output window A thin film aluminium electrode is deposited on the MCP side of the phosphor screen to act as an acceleration electrode for electrons and a naturally reflective membrane for the photons generated within the phosphor screen Page 14 Connection Diagrams ae ALI There are many possible combinations of Photek Image Intensifiers power supplies and gate units The tables below detail some of the more common configurations Configuration 1 This is the standard colour wiring convention for a Photek image intensifier Configuration 2 Where gating is required the blue wire may be replaced with a coax cable terminated with a SMA connector The outer conductor of the coax cable is internally connected to MCP Input Configuration 3 This configuration shows how a standard wired single MCP intensifier is connec
6. LLL hahaa MMI d Pr Diameter P t Pitch PHOTEK MCP Stack Configurations Microchannel plates are typically configured in single chevron or Z stacks with the latter two being used in MCP2xx and MCP3xx intensifiers MCP Output Window Single Chevron The bias angle is rotated by 180 degrees as each plate is added to the stack resulting in the chevron and Z stacks This reduces the chance of optical feedback from the phosphor screen to the photocathode and it enhances secondary emission at the front of the second and third MCPs and can result in improved PHD characteristics HA Ill TH TT Wi ill T Ill Hl AL HH H Hl HE HT mT HII fl Wy NNN sil HA HH HNHH HEP ENG HH INi AVL NUT THAT T WAHT HH NNN TTT TITI I IMM IMI Hl PTN TT ji HET NI ftl ftl HH HNH LATTA T l j Ji Y With a single MCP there is a physical limitation in gain of about 104 With gain values above 10 lon feedback can occur as the electron shower becomes more intense and this can reduce the life of the detector By stacking 2 or 3 plates in V or Z stack configuration lons generated in the 2 or 3 plate cannot travel back to the photocathode as they are blocked in the 180 degree interface between the two MCPs Photek Image intensifiers are available in a range of different micro channel plate configurations These include the
7. PH TEK ENVISAGE THE FUTURE Image Intensifier User Guide This User Manual is intended to provide guidelines for the safe operation of Photek MCP Intensifiers Please take particular note of pages 3 and 4 If you require any further details or assistance please contact Sales or visit www photek co uk PH TEK Contents Health and Safety AG VICE xc cccsinsicecscasacicctccevesecesicisatecsvaceinsectaateiasessuanarbestedaunseeestsanatese 3 uir c VO LOG nni 3 X Ray ROGIAUON spiana 3 Storage and Handling pria a 3 Operation with an External PSU iii 4 Operation with a Wrap Around or Flat Pack PSU eese 4 Image Intense Soo eius iieeseuaa vss a xo que suce uma ener ata 5 DODO CIC NO mM 5 M de of Operati OU rag iaia 5 PUN aa 5 Spectral Sensitivities of various Photocathodes rire 6 Photocathodes on Fibre Optic iii 6 Photocathodes on Quartz Fused Silica sees 7 Understanding Microchannel PIOLeS rina 8 WAG FO ES M E 8 MCP TIO OS E n E 8 Electrodes and End Spoiling iienaa e na a n O E TE E NOEN 9 PENA A Roll aaa 9 MCP Stack Configurations iii 10 MCP Resistance and Strip CUrrent iii 12 Underlays and MI 12 Ci PR RR ates 13 CEP
8. avelength in an input window and photocathode combination The materials used and the stoichiometry of the photocathode have a great bearing on spectral response Vision64 Photek s proprietary software is used for the testing and evaluation of Image Intensifiers This software is also available to purchase Page 22 PHOTEK Notes Photek Limited Tel 44 0 1424 850555 26 Castleham Road Fax 44 0 1424 850051 P H OT E K St Leonards on Sea sales photek co uk ENVISAGE THE FUTURE East Sussex TN38 9NS www Photek co uk United Kingdom Page 23
9. creen radiant emittance in W m to the irradiance on the photocathode in W m Limiting Resolution A measure of the ability to discern image detail by focusing a black and white resolution pattern onto the photocathode The spatial frequency value at 5 MTF is taken to be the limiting resolution and is expressed in Ip mm Luminescent Screens The choice of phosphor deposited on the output window is determined by two main considerations Required Spectral Range For example in applications where the screen is to be viewed directly by the naked eye a yellow green phosphor with peak radiant energy at around 550 nm is typically used Alternatively for photographic applications a blue phosphor such as P11 having a spectral output peaking at around 400 nm is generally more suitable Persistence A short persistence phosphor is necessary to evaluate rapidly occurring events whereas a longer persistence phosphor is of benefit where image luminance is fluctuating and needs to be integrated Page 20 LEN Luminous Sensitivity The responsivity of a photocathode to luminous energy in the form of a light source at a colour temperature of 2856 K It is the ratio of photoelectric emission to incident luminous flux expressed in microamperes per lumen uA Im Modulation Transfer Function MTF A graph describing the modulation of the image of a sinusoidal object as the frequency increases In measuring resolution as the line width an
10. d spacing are reduced there is a limit beyond which the contrast of the black and white line pattern cannot be lowered without the pattern becoming indecipherable The relationship between this contrast modulation expressed as a percentage and the number of line pairs is referred to as the MTF It is usually specified as a percentage at a particular number of line pairs per millimetre Ip mm Photocathode A photoelectric material which emits electrons when irradiated with photons Varying spectral response characteristics can be obtained by a combination of appropriate photocathode and input window material Photoelectric Gain Photoelectric gain is the number of photons out per photoelectron Photon Gain Photon gain is the number of photons out per photon in i e a function of wavelength because of photocathode efficiency so PHOTON GAIN DQE x PHOTOELECTRON GAIN Quantum Efficiency Terms Quantum efficiency QE is the ratio of the number of emitted photoelectrons to the number of incident photons usually expressed as a percentage at a particular wavelength QE can be calculated at any given wavelength from the formula 124x S 4 QE 1 Where S A is the cathode radiant sensitivity in mA W at wavelength A in nm Page 21 PH TEK It is important to distinguish between the responsive quantum efficiency RQE and the detective quantum efficiency DQE RQE is the fraction of input photons that give rise to primary electro
11. e illumination However the long term life of intensifiers will be reduced by operation at continuous high light levels The ABC circuit works by monitoring the screen current If the screen current approaches the pre set level the gain of the intensifier is automatically reduced to maintain the set screen current It should be noted that the ABC circuit does not protect the tube from damage caused by high focussed light levels over a small area of the detector as the total screen current may be within the pre set ABC level Page 4 PH TEK Image Intensifiers Introduction Image Intensifiers consist of three basic elements An input window capable of transmitting light over a particular spectral range that can span from the near UV to near IR with photocathode deposited on its inner surface e One or more microchannel plates MCPs to provide electron gain e An output window on which is deposited a suitable luminescent phosphor aluminium screen These elements are enclosed in a ceramic and metal housing with suitable leads for electrical connection Mode of Operation When an image is focused onto the photocathode it emits electrons proportional to the intensity of the incoming light The electron image is focused onto the MCP which amplifies the electronic image before it is focused onto the luminescent screen where the optical image is reproduced Focusing is by means of the proximity wafer structure This consists of a planar phot
12. e similar to those given for single MCP tubes Double and triple MCP stages produce a peaked pulse height distribution enabling the user to set electronic thresholds to distinguish between camera noise and photon events In these applications input fluxes should be in the order of a thousand photons per second per cm 10 W cm 10 lux or 10 foot candles This in human terms is not visible to the eye Page 18 LEN Coupling to other devices When coupling other devices to the screen three factors should be considered Avoid applying excessive pressure to the screen optic of the intensifier To do so could crack the fibre optic seal and cause the tube to leak to atmospheric pressure rendering it useless Charging effects can occur when optics are directly coupled to each other To avoid this the intensifier can be supplied with a conducting coating ITO on the outside surface of the screen optic This can then be connected to a grounded wire which eliminates static charge effects Some devices coupled to the image intensifier may require the intensifier to operate with a higher than recommended screen brightness The level of brightness should be kept to a minimum in order to maintain a linear dynamic amplification range The life of an image intensifier will be reduced if operating continuously at an output brightness of greater than 5 Cd m Photek recommends a screen output brightness of 3 Cd m for a P20 phosphor The output br
13. ightness of an image intensifier is also related to anode current This factor should be considered when using image intensifiers that have screen phosphors with a lower efficiency than a P20 phosphor Glossary of terms Contrast Transfer Function CTF The CTF is the square wave spatial frequency amplitude response and is frequently quoted as it is easier to measure than MTF Either form of response can be converted to the other Equivalent Background Illumination EBI The screen of an intensifier will have an inherent finite brightness when the supply voltage is applied and there is no incident light on the photocathode The EBI is the input illumination required to give an increase in screen brightness equal to this background brightness Page 19 PH TEK First Generation Tubes Tubes in which the primary photoelectrons are accelerated by a high electric field to energies of around 25 keV and electrostatically focused onto a phosphor screen The energy gained by the electrons in the field is released as a flash of light in the phosphor screen With modern screens several hundred photons may be released by each electron impact Gain Terms The gain is usually defined in two ways related to photocathode spectral response Luminous Gain The ratio of the phosphor screen luminous emittance Cd m to the illuminance incident on the photocathode lux at a colour temperature of 2856 K Radiant Gain The ratio of the phosphor s
14. nce High Output Technology MCPs referred to as HOT are much lower in resistance than standard MCPs and have the advantage that their recovery time is much faster This is particularly important in pulsed or high speed gating applications where local areas of the MCP are repeatedly stimulated Depending on the resistance of the MCPs special high voltage power supplies may be required It should also be noted that low resistance MCPs may not be suitable for applications requiring very low dark noise particularly in photon counting detectors Underlays and Meshes Most photocathodes have a relatively high resistance For gating applications it is necessary to reduce the photocathode resistance and this can be done by applying an underlay or mesh to the input window prior to deposition of the Photocathode Underlays typically involve evaporating a transparent conducting layer directly onto the input window Depending on the gating characteristics required the transmission of the layer will be in the range 50 to 98 96 A 50 transmission underlay should allow gating to 5ns on a 25mm image intensifier whereas a 95 transmission underlay may only achieve 100 ns gating The disadvantage of thick underlays is that the spectral sensitivity can be significantly reduced depending upon the wavelength of interest For faster gating performance or where loss of spectral sensitivity cannot be tolerated a mesh can be photo etched onto the input wi
15. ndow Standard meshes are 10 um lines on a 100 um pitch however these can be visible in a flat field image High resolution meshes with 2 um lines on a 20 um pitch have been developed which are almost invisible Page 12 LEN Gating Most image intensifiers have gating capabilities This allows the image intensifier to be used as a fast optical switch or shutter The gating speed is proportional to the RC associated with the gap between the photocathode and MCP where R is the resistance of the photocathode and C is the capacitance of the gap between the photocathode and MCP Multi alkali photocathodes generally have a lower resistance than Bialkali or Solar Blind cathodes To achieve ultra fast gating performance it is necessary to reduce the photocathode resistance by applying a conducting underlay or mesh to the window substrate The capacitance is proportional to the surface area of the cathode and inversely proportional to the gap between cathode and MCP Smaller area detectors or detectors with a large cathode to MCP gap will gate faster The table below outlines typical cathode capacitance and is for guidance only Active Cathode to Ceramic Gap Capacitance Total Diameter mm MCP Gap Capacitance pF pF Capacitance um pF Page 13 LEN Gate Units Maximum Li Power Rise Fall Minimum Propagation Gate Unit Repetition 1 Supply Rate kHz Time ns Width ns delay ns GM10 50B 110 GM300 3N 300 GM30
16. ng labels and notices must be provided on equipment and in operating manuals High Voltage Equipment must be designed so that operators cannot come into contact with high voltage circuits Tube enclosures should have fail safe interlocked switches to disconnect the primary power supply and discharge all high voltage capacitors before allowing access X Ray Radiation All high voltage devices produce X rays during operation and may require shielding Storage and Handling Avoid storage or operation of image intensifiers at temperatures greater than 40 C Room temperature is preferred 21 C Protect the cathode from intense focused light sunlight and lasers even when not running the image intensifier as this can lead to local thermal overloads and cathode damage Avoid excessive shock or vibration to the image intensifier as this could damage delicate internal components such as the MCP Keep the optics protected from dirt and grease as they could become scratched Avoid running the image intensifier for long periods of time with a fixed image especially if it is bright as there is a possibility that a permanent burnt in image will occur Excessive axial force will crack the screen pyroceram material used to seal the output window into the image intensifier body This renders the tube inoperable Page 3 PH TEK Operation with an External PSU If the image intensifier is to be powered by the customer s own power supply u
17. nit it is important to gradually increase the applied voltage to the required level It is equally important to gradually reduce and monitor voltages when powering off the image intensifier IMPORTANT e The maximum voltages are documented in the Test Data Summary and must NEVER be exceeded e The voltage difference between the photocathode and the MCP input must never exceed 200 V unless specified on the Test Data Summary e The brightness of the phosphor screen should be kept below 5 Cd m Ideally 3 Cd m is required for a typical P20 or P43 phosphor Customers providing their own power supplies should discuss the suitability of the power supply with Photek Ltd to ensure that it is compatible with the image intensifier being ordered particularly with respect to insulation encapsulation earth point etc Operation with a Wrap Around or Flat Pack PSU If the image intensifier is supplied with a Wrap Around or Flat Pack power supply a 5 V DC supply is required typical operating current 25 125 mA Gain is adjustable with a 0 5 V variable DC supply When switching on ensure that the image intensifier is in dark conditions Gradually increase illumination until a glow or image if using a lens to project an image onto the input optic is seen at the screen An optional extra for Wrap Around or Flat Pack PSUs supplied by Photek is the gain and automatic brightness control ABC which ensures a measure of protection from excessiv
18. ns and DQE is the fraction of input photons that give rise to discrete output events In MCP devices the DQE is approximately 50 60 of the RQE due mainly to the effect of the open area ratio of the MCP In a proximity diode however the DQE is around 85 of the RQE the difference being due only to absorption of electrons by the aluminium backing of the phosphor screen Radiant Sensitivity Radiant Sensitivity is the responsivity of a photocathode to monochromatic light expressed in milliamps per watt mA W at the prescribed wavelength Resolution Pattern A pattern comprising a series of sets of lines at progressively smaller line widths and spacings that is used to determine the number of lines per millimetre that an optical system is capable of resolving or separating clearly For modulation transfer function MTF measurements the pattern must have lines with a sine wave distribution of brightness Second Generation Tubes Here the primary photoelectrons are multiplied by an MCP which is placed in close proximity to both the photocathode and the phosphor screen therefore preserving the spatial coherence of the electron image The electron multiplication enables far greater intensification to be achieved than in first generation devices up to hundreds of thousands of photons being released by the screen for each primary electron entering the MCP Spectral Response The Spectral Response is the variation of sensitivity with w
19. ocathode MCP and screen in parallel and very close proximity to each other Applying suitable high voltages between these electrodes ensures electron transmission gain and acceleration giving a non inverted distortion free image 100 Input Windows Photek can supply image intensifiers with a range of input windows including co e e e N eo Glass e Fibre Optic 9 c 60 LY c e Glass S e E 50 fe e Fused Silica 3 3 E 40 2 e MegF2 amp e Others on request Je 20 5 E E r h eo Typical transmission properties of each of the windows are shown in the graph to E A dis L the right Wavelength nm Page 5 CLER Spectral Sensitivities of various Photocathodes Image intensifiers having borosilicate glass or fibre optic windows will not operate below the cut off frequency of these materials i e 300 350 nm despite the fact that the photocathode still has adequate sensitivity in this region However Fused Silica Magnesium Fluoride or Sapphire input windows will extend the spectral response to the limit imposed by the transmission of these materials 180 nm for fused silica 150 nm for Sapphire and 110 nm for MgF2 Photocathodes on Fibre optic Typical Cathode Sensitivities on Fibre Optic PHeTEK Page 6 PHOTEK Photocathodes on Quartz Fused Silica Typical Cathode Sensitivities on Quartz PH TEK oe Bialkali
20. range 40 1 to 80 1 Gain of a MCP is proportional to its I d ratio the secondary emission coefficients of the MCP the applied voltage and end spoiling Page 8 Electrodes and End Spoiling During the final stage of manufacturing a MCP an electrode made from Inconel or Ni Cr is evaporated onto the input and output faces of the MCP leaving a surface resistance of approximately 100 Q square During evaporation of the output electrode the coating penetrates each pore by a depth of between 0 5 and 3 pore diameters thus removing the secondary emission characteristic from the end of the MCP pore For high resolution detectors such as image intensifiers greater end spoiling results in a more collimated electron cloud producing improved spatial resolution This can result in lower maximum gain Open Area Ratio The Open Area Ratio OAR is the ratio of the area occupied by the MCP pores to the surface area of the MCP For hexagonal arrays OAR 7 2V3 x d p where d is the channel diameter and p is the pitch For example 10 12 MCPs have an OAR of 63 96 However custom MCPs can be manufactured with higher open area ratios by increasing the hole diameter and keeping the pitch the same Page 9 PH TEK L Ww 0 5d a P 151 ilii mmm n 1 INNO MI i i I nu MNT A SETETE ULI L MEM l nul Ma MMI LL Wi MM at 1 BIN TTI Mt RARA i vit ull MI ll MI ARALL i
21. s offers some protection not only for the intensifier but for any light sensitive device coupled to the output screen of the image intensifier Typical operating illumination levels depend upon cathode spectral response and the number of channel plates used in the image intensifier Single MCP Intensifiers With an S25 photocathode the optimum operating conditions are in the range 10 to 107 lux 10 to 10 foot candles This is equivalent to a photocurrent of around 2 pA The spectral response curve supplied with the tube can be used to calculate radiant input in terms of watts or photons second for specific wavelengths to give a suitable photocurrent of about 2 pA Image intensifiers supplied by Photek can be calibrated in terms of luminous gain and or radiant gain at wavelengths specified by the customer Multi MCP High Gain Photon Counting Intensifiers As the light level is reduced the image gets weaker and harder to see The temptation is to specify a tube with higher gain However this will not always solve the problem which is more about the small number of photons available to produce an image within the integration time of the eye or electronic readout Improved performance can be achieved by frame averaging or electronic integration Multi MCP tubes are often recommended in conjunction with fast phosphors for example P46 and P47 to overcome the low luminous efficiencies In this case the recommended input illumination levels ar
22. stack configuration I d ratio and the pore pitch ratio of the microchannel plate The table on page 12 shows typical configurations Page 10 qu AI MCP1xx Single plate image intensifier Typical MCP Configuration I d ratio diameter pitch um 40 1 10 12 Input Photons 55 10 12 AM 55 1 6 8 60 1 4 5 MCP2xx Image Intensifier Typical MCP Configuration I d ratio diameter pitch um 40 1 10 12 55 1 10 12 55 1 6 8 60 1 4 5 Output Photons AA Li I V Vt MT lli Ll MCP3xx Image Intensifier Typical MCP Configuration I d ratio diameter pitch um 40 1 10 12 Output Photons 55 1 10 12 v J Me 55 1 6 8 60 1 4 5 MCP3xx Image Intensifier Typical MCP Configuration Output Window I d ratio diameter pitch um Output Photons zz eee Me Front MCP 60 1 10 12 Phosphor Screen m THAT MITTEN HAT III ul Input Photons AA uve uu Rear MCP 60 1 10 12 TT TTT TY TET HH H l unl WWI Ul MCP3xx Image Intensifier Typical MCP Configuration I d ratio diameter pitch um Front MCP 40 1 10 12 Rear MCP 80 1 10 12 Output Window HR HE if fl HH HT EHE HT Output Photons Input Photons AA Vive AAA vuv HE H HH HT LEBEN I I hl Phosphor Screen Page 11 PH TEK MCP Resistance and Strip Current MCP manufacturers generally specify the strip current at 1000 V however Photek normally refer to MCP resista
23. ted to a FP610 power supply The green ITO wire if fitted must be connected to ground Configuration 4 This configuration shows how a single MCP intensifier is wired directly to a FP610 power supply The ITO connection if required is connected internally Configuration 5 This configuration shows how a standard wired multi MCP intensifier is connected to a FP630 power supply The green ITO wire if fitted must be connected to ground Standard Wire Colours Cathode MCP Input Red MCP Intermediate MCP Output Phosphor Screen ITO MCP2xx and MCP3xx onl Yellow These wires are not always fitted ITO Wire should be connected to Ground Standard Wire Colours Cathode MCP Input MCP Intermediate MCP Output White MCP2xx and MCP3xx onl Phosphor Screen ITO These wires are not always fitted ITO Wire should be connected to Ground MCP1xx Image Intensifier FP612 Power Suppl Cathode MCP Input Red MCP Output Phosphor Screen Yellow Yellow Phosphor Screen ITO Gain Adjust Orange Violet ITO Wire should be connected to MCP Input and Ground MCP1xx I ifi CP1xx Image Intensifier FP612 Power Suppl Blue Cathode MCP Input Red Black MCP Input kd wii el Gaal Phosphor Screen Gain Adjust Phosphor Screen 5 Monitor Violet Internal ITO Connection if required MCP2xx or MCP3xx Image Intensifier FP632 Power Suppl Cathode Blue Blue cathode MCP Input Red c Black MCP Input
24. xial Gain Adjust Phosphor Screen d I Monitor Phosphor Screen ITO ITO Wire should be connected to MCP Input and Ground Page 16 Configuration 11 For image intensifiers supplied with a Wrap Around power supply 5 V power O V and 0 to 5 V gain adjustment connections are required Configuration 12 For image intensifiers supplied with a Wrap Around power supply and internal GM10 50 gate unit 5 V power OV and 0 to 5 V gain adjustment and TTL trigger connections are required Configuration 13 For image intensifiers supplied with a gated Wrap Around power supply 5 V power OV and O to 5V gain adjustment and TTL trigger connections are required au ALI MCP1xx with WP612 no gating MCP2xx with WP632 no gating MCP3xx with WP632 no gating MCP1xx with WP610 GM10 50 MCP2xx with WP630 GM10 50 MCP3xx with WP630 GM10 50 MCP2xx with WP620G50 Page 17 PH TEK Illumination Levels In considering maximum input light levels it is important to remember that the life of an intensifier is directly dependent on illumination levels while it is operating The Wrap Around PSU supplied by Photek has a photocathode current limiting resistor of approximately 2 GO which provides bright source protection BSP An automatic brightness control ABC may also be incorporated in the PSU in order to limit the output brightness This is achieved by controlling the gain of the intensifier at varying input levels Thi
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