HICATT High Speed Intensifier

HICATT High Speed Intensifier

Nb of stages

2

Tube size

18 or 25 mm

Max Rep Rate

0.1 to 1 MHz continuous/ <10 MHz in burst mode

Shortest Gate duration

3 ns/25 ns/40 ns/ 100 ns/ 200ns

Photocathodes/spectral sensitivity

Gen 2 (S20, S20B, S25) or Gen 3 (GaAs, GaAsP )

Phosphors

P46 or P47

The HiCATT is an intensified camera attachment specifically designed for use in combination with high-speed and ultra-high speed cameras (1 MHz). It is used to amplify low light level images up to 50000 times ( tube and wavelength dependent)  thereby boosting the sensitivity of the attached high-speed camera and enabling high-speed, low light-level imaging. The following video is a gas explosion in a mine test chamber  acquired at 2o,000 fps with a HICATT coupled to a high speed camera.

 

The HiCATT attaches to all major brand high-speed cameras by using a high quality lens coupling. The hybrid Image Intensifier of the HiCATT consists of 2 stages and can be delivered with a diameter of either 25 mm or 18 mm. The first stage is a Gen II or Gen III proximity-focused MCP intensifier and offers a very high, adjustable gain. The second stage is a proximity-focussed Gen1 booster, producing the extra high output brightness required for imaging at high frame rates. In its gating mode the first stage functions as a fast electro-optical shutter with effective exposure times down to the nanosecond regime.

The intensifier can be operated at repetition rates of up to 1 Mhz in continuous mode and 5 MHz in bursts. A series of different intensifier control units provide functionality ranging from analog gain control to full digital control including an internal trigger generator and programmable gate trains. With a wide range of Gen II and Gen III image intensifiers the HiCATT offers high sensitivity down to single photon level and the optimal spectral bandwidth for your application. Different models covering a range in spectral sensitivity, phosphor, spatial resolution, gain, linearity, minimum gate width and gating frequency are available. Standard, the first stage image intensifier of the HiCATT is equipped with a single MCP. Dual MCP image intensifiers are available on request.

Image Intensifier Layout

When the HiCATT is mounted to a lens or microscope, the incoming light (a) is focused onto the entrance window of the image intensifier (b). The image intensifier converts the optical image to electrons at the photocathode, amplifies this electron image at the micro-channel plate (MCP), and re-converts the electrons into photons at the anode screen. The second image intensifier (booster, c) further amplifies the signal. At the output of the hybrid intensifier a relay objective (d) is mounted with a magnification that matches the intensifier to the high-speed camera sensor (e).

For time-resolved imaging a gate unit (f) is used together with the image intensifier to yield an electro-optical shutter. The gate unit either generates a high voltage pulse signal or follows an external TTL pulse. The pulse width is variable and follows a TTL input pulse over the range from less than 3 ns to DC at a repetition rate up to 300 kHz.

Spectral response and phosphor decay time

Phosphor Efficiency Decay time to 10% Decay time to 1%
P43 (optional) 20 photons/e-/kV 1.5 ms 3 ms
P46 (standard) 6 photons/e-/kV 500 ns 2000 ns

**P20, P24 and P47 available on request

 

Intensifier working principle

On the photocathode(1) photons get converted into electrons. These are accelerated in an electric field towards the Multi Channel Plate (MCP, 2) and hit the channel walls. Depending on the voltage across the channel, multiple electrons are generated by secondary emission. This cloud of electrons gets accelerated towards the anode screen (3), where the electrons are converted back into photons by the phosphor layer. These photons are guided by a fiberoptic faceplate (3) to the entrance of the second stage (booster). Again photons are converted to electrons by the photocathode (4) and accelerated to the anode screen (5) where the image appears. The relay lens (6) transfers the image from the back of the intensifier onto the mounted camera.

 

Photocathodes

The photocathode is the entrance of the image intensifier. This is where the incoming photons are converted to electrons. The quantum efficiency of the photocathode material specifies how efficient this conversion is for each wavelength.

Second generation image intensifiers

The photocathode of a second generation image intensifier can have a quantum efficiency of up to 25%.S25 photocathodes are only available in the 18 mm diameter image intensifiers.

Second generation high QE image intensifiers

The photocathode of a second generation high QE image intensifier can have a quantum efficiency of over 30%.Please note that these image intensifiers are only available with a diameter of 18 mm.

Second generation fast-gated high QE image intensifiers

The photocathode of a second generation high QE image intensifier can have a quantum efficiency of over 25%. Please note that these image intensifiers are only available with a diameter of 18 mm.

Third generation image intensifiers

The photocathode of a third generation image intensifier can have a quantum efficiency of up to 50%.

Description

The HiCATT is an intensified camera attachment specifically designed for use in combination with high-speed cameras. It can be used to amplify low light level images to a level up to 30000 times, thereby boosting the sensitivity of the attached high-speed camera and enabling high-speed, low-light level imaging.

The HiCATT attaches to all major brand high-speed cameras by using a high-quality lens coupling. The hybrid Image Intensifier of the HiCATT consists of 2 stages and can be delivered with a diameter of either 25 mm or 18 mm. The first stage is a Gen II or Gen III proximity-focused MCP intensifier and offers a very high, adjustable gain. The second stage is a proximity-focussed Gen1 booster, producing the extra high output brightness required for imaging at high frame rates. In its gating mode the first stage functions as a fast electro-optical shutter with effective exposure times down to the nanosecond regime.

The intensifier can be operated at repetition rates of up to 1 Mhz in continuous mode and 5 MHz in bursts. A series of different intensifier control units provide functionality ranging from analog gain control to full digital control including an internal trigger generator and programmable gate trains. With a wide range of Gen II and Gen III image intensifiers the HiCATT offers high sensitivity down to single photon level and the optimal spectral bandwidth for your application. Different models covering a range in spectral sensitivity, phosphor, spatial resolution, gain, linearity, minimum gate width and gating frequency are available. Standard, the first stage image intensifier of the HiCATT is equipped with a single MCP. Dual MCP image intensifiers are available on request.

Image Intensifier Layout

When the HiCATT is mounted to a lens or microscope, the incoming light (a) is focused onto the entrance window of the image intensifier (b). The image intensifier converts the optical image to electrons at the photocathode, amplifies this electron image at the micro-channel plate (MCP), and re-converts the electrons into photons at the anode screen. The second image intensifier (booster, c) further amplifies the signal. At the output of the hybrid intensifier a relay objective (d) is mounted with a magnification that matches the intensifier to the high-speed camera sensor (e).

For time-resolved imaging a gate unit (f) is used together with the image intensifier to yield an electro-optical shutter. The gate unit either generates a high voltage pulse signal or follows an external TTL pulse. The pulse width is variable and follows a TTL input pulse over the range from less than 3 ns to DC at a repetition rate up to 300 kHz.

Spectral response and phosphor decay time

Phosphor Efficiency Decay time to 10% Decay time to 1%
P43 (optional) 20 photons/e-/kV 1.5 ms 3 ms
P46 (standard) 6 photons/e-/kV 500 ns 2000 ns

**P20, P24 and P47 available on request

 

Intensifier working principle

On the photocathode(1) photons get converted into electrons. These are accelerated in an electric field towards the Multi Channel Plate (MCP, 2) and hit the channel walls. Depending on the voltage across the channel, multiple electrons are generated by secondary emission. This cloud of electrons gets accelerated towards the anode screen (3), where the electrons are converted back into photons by the phosphor layer. These photons are guided by a fiberoptic faceplate (3) to the entrance of the second stage (booster). Again photons are converted to electrons by the photocathode (4) and accelerated to the anode screen (5) where the image appears. The relay lens (6) transfers the image from the back of the intensifier onto the mounted camera.

Researchers around the world are using the HiCATT in their combustion studies involving OH* laser-induced fluorescence (LIF) and chemiluminescence. To avoid motion blur and to see the detailed structures, a very short exposure time is required. This reduces the light intensity that is detected during each exposure. The HiCATT boosts the light intensity to ensure clear images at high frame rates.