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Forensic infrared viewer

JASEN (Russian: ЯСЕН) 1 was a Generation 1 image intensifier, also known as a night vision device (NVD), for infrared (IR) and ultraviolet (UV) imaging, developed in 1957 in the Soviet Union (USSR) and manufacturered 2 at the Zagorski Optical-Mechanical Plant (ZOMZ) near Moscow (Russia). The device was intended for use in criminal investigations, for example to see in the dark during an observation and as a forensic investigation tool. It is also known as S-270 (С-270) and INFRAM.

JASEN consisted of two parts: the IR/UV viewer shown in the image on the right, and an IR light source 3 that could be fitted to its side, each powered by internal rechargeable NiCd battery cells. In addition, the device could be used in combination with any other IR/UV light source.

The device was originally developed for use by the police in criminal investigations, especially during surveillance and observations, as it is a rather compact unit, and allows the user to see in absolute darkness, as long as the target is illuminated by a strong infrared (IR) light source.

In surveillance, the device was also used without its infrared light source, to check if an IR viewer was used by someone else, allowing an agent to check whether he/she was under surveillance.

The image on the right shows a typical JASON viewer, with the standard short lens, which can be adjusted between 15 cm and infinity (∞). In addition, the eyepiece can be adjusted to match the eye's refraction between -3 and +3 diopter. Other (telephoto) lenses were available as well.
Jasen IR viewer in upright position

JASEN (S-270) was first released in 1957, and was in production until at least 1992. In most (but not all) cases, the first two digits of the serial number represent the production year. This means that the device featured here was made in 1974. Over the years, the design of the IR light source – which originally had the same size as the viewer – was changed several times. The last known version has an IR lamp with a large diameter, a pistolgrip and a large external battery pack.

The device itself has hardly changed over the years. The Kenotron rectifier was replaced at some point by cascaded semiconductor diodes, and the name was changed to INFRAM (ИНФРАМ). In a modified form – for use in photographic KGB laboratories – it is also known as S-330M (BUK) [2].

  1. JASEN (ЯСЕН) is the Russian word for CLEAR.
  2. It is possible that the device was also manufactured by other companies.
  3. The IR light source is missing from the device shown here.

Jasen IR viewer in horizontal position JASEN IR viewer - Font size Jasen IR viewer in upright position IR input port Adjustable eyepiece (ocular) Spare Kenotron valve
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Jasen IR viewer in horizontal position
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JASEN IR viewer - Font size
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Jasen IR viewer in upright position
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IR input port
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Adjustable eyepiece (ocular)
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Spare Kenotron valve

The diagram below gives a quick tour around the controls and features of the JASEN viewer. At the top is the image intensifier that has a filtered lens at the front and an adjustable ocular at the rear. It can be used in upright position – as shown above – or horizontally – as shown below.

The device is powered by just 2.4V DC, supplied by two rechargeable 1.2V NiCd batteries that are installed in the cylindrical compartment at the bottom/front. As the original NiCd batteries are no longer available, provisions must be made to fit contemporary alternatives. Power can be turned ON permanently by shifting the power button towards the rear, or momentarily by pushing it in, which is sufficient in most cases as the image intensifier holds the HT charge for several minutes.

The following versions and variants of JASEN are currently known:

  • JASEN, S-270 (С-270)
    This is the initial version of the device. It consists of the JASEN IR/UV viewer and a same-size infrared light source that can be mounted to its left side. The device featured above, is of this type.

  • BUK, S-330M (С-330М)
    This is a special version that was adapted by the KGB's 11th directorate for use in photo­graphic darkrooms, to observe black-and-white films whilst they were being developed.

    This is a later version of the S-270, in which the Kenotron rectifier valve of the HT unit has been replaced by semiconductor diodes. This version comes with a different light source, and has the name ИНФРАМ engraved on the side.

  • PLYN (TI-339-0)
    Version of the S-270, modified for the Czech intelligence service StB. This version has a larger battery pack that is attached at the bottom, and a fixed IR light source that is mounted at the right side of the device. PLYN is the Czech word for GAS.

    Czech variant of the Soviet BUK (S-330M), in grey hamerite enclosure. Intended for use in darkrooms and photographic processing laboratories of the StB.
Jasen viewer with IR light source. Image kindly supplied by Detlev Vreisleben [1]. Example of a complete S-270 with IR light source and leather carrying case. Source unknown. Example of the INFRAM version (1992). Source unknown. Example of the INFRAM version (1992). Source unknown. Czech version of JASEN (PLYN TI-339-0). Image kindly supplied by Detlev Vreisleben [1]. Czech version of JASEN (PLYN TI-339-0). Image kindly supplied by Detlev Vreisleben [1]. Czech PLYN (TI-339-0) and Boucek (Buk). Image kindly supplied by Detlev Vreisleben [1].
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Jasen viewer with IR light source. Image kindly supplied by Detlev Vreisleben [1].
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Example of a complete S-270 with IR light source and leather carrying case. Source unknown.
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Example of the INFRAM version (1992). Source unknown.
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Example of the INFRAM version (1992). Source unknown.
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Czech version of JASEN (PLYN TI-339-0). Image kindly supplied by Detlev Vreisleben [1].
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Czech version of JASEN (PLYN TI-339-0). Image kindly supplied by Detlev Vreisleben [1].
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Czech PLYN (TI-339-0) and Boucek (Buk). Image kindly supplied by Detlev Vreisleben [1].

Because of its compact design, JASEN could be adapted for a wide range of applications, such as:

JASEN was suitable for observations at night time, in which case the target had to be illuminated by a strong infrared (IR) light source. It was also suitable for surveillance jobs, for example when entering a room in total darkness in order to avoid attracting attention. In that case, the local IR light source – typically the one that could be attached to the side of the device – was used.

Although the use of an IR light source allows an operative to see in total darkness, it is also potentially dangerous, as the IR light can be detected from miles away by someone with a similar IR viewer. This is particularly the case when the subject is aware of being under surveillance.

In criminal cases, JASEN was used as a forensic investigation tool. As it is sensitive to infrared (IR) as well as ultraviolet (UV) light, it is the perfect tool for the detection of forged documents. In that case, the device has to be used in a darkened (preferrably dark) room, so that the IR-filter in front of the lens can be removed. By illuminating the document with both IR and UV light, any changes that were made to paper, printed text, ink, glue, paint, coating and even a signature, will light up.

Example of a footprint that is revealed with UV imaging [6]

UV can light up bruses on a person's body, even when they are partially healed and are not visible to the naked eye under visible light. It can also detect fingerprints on paperwork and shoe-prints on a smooth surface, that are otherwise completely invisible. In forensics, this technique is known as Reflected-UV Imaging [6]. Note that for this type of application, an ultraviolet light source with a suitable wavelength is required, and that the IR-filter in front of the lens has to be removed.

 Read this report about the forensic use of UV

During a covert operation, JASEN could be used as one half of a signalling system, in which one party operates an IR flashlight, whilst the other party monitors it. The flashlight can be used to trigger an event (e.g. to mount an attack), as an emergency distress signal, a marker or a beacon.

A good example of such a beacon, is the pocket FRS/MS-2000M military distress marker made by the US company Fedcap Rehab SVCS, as shown in the image on the right. The device measures 113 x 54 x 27 mm and weights just 150 grams.

The device is powered by two AA-size penlight batteries that are installed at the bottom, and is small enough to be carried in the pocket. At the top is a removable infrared (IR) filter cap behind which a large flash bulb is mounted.

 More information

Top side with IR filter removed

Darkroom — S-330M BUK   БУК
As a spin-off from JASEN (S-270), the 11th directorate of the KGB developed BUK (Russian: БУК) – also known as S-330M (С-330М) – as an aid when processing film from subminiature cameras like the ZVOEK, ZAGADKA and ZALIV, and – to a lesser extent – ZODCHI, TOCHKA and MINOX.

Operatives often made technical mistakes when photographing documents and in-door scenes, e.g. by under-exposing or over-exposing the films. OT officers started ex­peri­menting with longer and shorter development times of the negatives. They discovered that, by leaving the exposed films longer or shorter in the chemical developer, the quality of the negatives could be improved drastically, leading to better prints.

As the exposed films were insensitive to infrared light (IR), it was possible to use JASEN to watch the films whilst they were being developed [2].
Czech PLYN (TI-339-0) and Boucek (Buk). Image kindly supplied by Detlev Vreisleben [1].

The KGB's 11th directorate subsequently modified JASEN, so that it could be powered externally, and gave it a different permanent IR light source and a suitable support arm for mounting it to the wall of the darkroom. The new device became known as BUK (Russian: БУК) and is also known as S-330M (С-330М). According to Keith Melton in his excellent book The Secret History of KGB Spy Cameras, BUK was manufactured at the Mechanical Factory of Krasnogorsk (KMZ) [2].

The image above, shows the Czech variant of BUK — known as BOUČEK — in its grey hamerite enclosure, as it is on public display is the Police Museum in Prague (Czech Republic). At the left is PLYM, the Czech version of JASEN, modified for use by the repressive intelligence service StB.

JASEN is housed in a strong die-cast alloy body, that has not changed very much over the years. It measures 135 x 100 x 40 mm and weights just 600 grams, batteries included. The interior can be accessed by removing 8 recessed screws from the right side, and taking off the right panel.

This reveals the contents of the device, as shown in the illustration above. The most important part is the image intensifier tube, that is fitted directly between the lens and the ocular [3]. It is powered by a high voltage, supplied by the large brown HT block at the centre of the device.

Inside the HT block, are a voltage transformer – that converts the 2.4V battery voltage into the HT voltage for the image intensifier – and a so-called Kenotron: a high-voltage rectifier tube, which is basically a further development of the Fleming Valve, invented by Irving Langmuir. 1
Image intensifier tube

At the bottom rear is the transistor-based oscillator that drives the HT transformer. It is powered by two 1.2V batteries in the cylindrical compartment at the bottom front. A micro-switch, fitted behind the battery compartment, acts as the power switch. Note the common domestic TL-starter that it is fitted in the rear corner. It is used here to protect the circuit against excessive voltages.

As the HT block is completely sealed, we have made a couple of x-rays that allow us to see what is inside. At the centre of the HT block is the Kenotron rectifier valve. It can be replaced via the circular threaded access port in the middle of the front panel. The x-ray images 2 also clearly show how the image intensifier tube is constructed. A spare Kenotron valve is also available.

The Generation 1 image intensifier tube that is used in the JASEN viewer, is sensitive to visible as well as invisible light, with two peaks: one in the infrared (IR) spectrum, and one in the ultraviolet (UV) spectrum. As the device is also sensitive to ambient daylight, it is important that the target (i.e. the input port) is protected against excessive levels. This is usually done by placing a strong IR filter over the lens. When using the device to detect UV light, this filter has to be removed.

  1. The Kenotron was invented in 1914 by Irving Langmuir at General Electric. It is a high-voltage version of the Fleming valve, and was used for many years in the power circuits of x-ray tubes [4][5].
  2. Images made with Creative Electron TruView Prime.  More

Interior Image intensifier tube Power switch and electronics board HT unit with transformer and Kentron valve TL starter,electronics board and batteries HT unit with Kenotron Image intensifier tube Spare Kenotron valve
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Image intensifier tube
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Power switch and electronics board
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HT unit with transformer and Kentron valve
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TL starter,electronics board and batteries
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HT unit with Kenotron
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Image intensifier tube
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Spare Kenotron valve

Below is the checklist of what is believed to be the first version of JASEN, in which valves (tubes) were used in the electronic circuits. In the 1970s, the valves were replaced by transistors, and in the 1980s, the Kenotron rectifier tube was replaced by cascaded semiconductor diodes.

# Description Translations Qty
1 Светофилтр ИК Infrared filter 1
2 Светофилтр УФС Ultraviolet filter 1
3 Лампа УФО 4А Lamp UFO-4A 1
4 Лампа ЦМ-33 Lamp CM-33 1
5 АккымулЯтор Д-02 Rechargeable battery V-02 2
6 Предохранител ПМО 0,15 Fuse 0.15 A 4
7 Кенотрон ЦКБ-1 Kenotron (rectifier) CKB-1 1
8 Салфетка 200 × 200 Napkin 1

Missing items
The following items are currently missing from the JASEN in our collection:

  • Infrared light source (same size as JASEN viewer)
  • Ultraviolet filter
HT   High Tension
Common expression for a high-voltage power supply, typically in the range of several hundreds to several thousands of Volts.
IR   Infrared
Invisible light beyond the red end of the visible spectrum, typically with a wavelength above 710 nm.
KGB   Komitet Gosudarstvennoy Bezopasnosti More
National Security Agency of the Soviet Union from 1954 to 1991 (Committee for State Security). Successor to the Cheka, the NKGB and the MGB. Since 1991 known as Federal Security Service (FSB). In the context of this page, KGB is often synonymous with any Soviet intelligence service.
NVD   Night Vision Device
OT   Operational Techniques
OTU   Operative Technical Directorate
Senior unit within the KGB that developed special equipment like surveillance cameras, bugs and covert communication devices.
UV   Ultraviolet
Invisible light beyond the purple end of the visible spectrum, typically with a wavelangth below 390 nm.
  1. Infram user manual (Russian)
    Date uknown, but probably ~ 1990. 1
  1. Document kindly supplied by Detlev Vresileben [1].

  1. Detlev Vreisleben, JASEN IR Viewer
    Personal correspondence, June 2019.

  2. H. Keith Melton et al., The secret history of KGB Spy Cameras
    ISBN 879-0-7643-5616-2. 2018. p. 35.

  3. Wikipedia, Image intensifier
    Retrieved June 2019.

  4. Wikipedia, Kenotron
    Retrieved June 2019.

  5. Wikipedia, Fleming valve
    Retrieved June 2019.

  6. Dr. Austin Richards, Reflected Ultraviolet Imageing for Forensics Applications
    Brooks Institute of Photography, Santa Barbara, CA (USA). 28 March 2010.
Further information
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© Crypto Museum. Created: Sunday 02 June 2019. Last changed: Monday, 10 June 2019 - 05:35 CET.
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