The Watec Video CCD

This video camera is still available, but is being phased out in favour of the slim USB camera, which is entirely digital.

SONY CCD Device Structure

• B/W Sony ICX419ALL Interline CCD image sensor
• Optical size: Diagonal 8mm (nominal 1/2 inch sensor)
• Number of effective pixels: 752 (H) x 582 (V) approx. 440K
• Total number of pixels: 795 (H) x 596 (V) approx. 470K pixels
• Chip size: 7.40mm (H) x 5.95mm (V)
• Unit cell size: 8.6µm (H) x 8.3µm (V)
• High sensitivity, Low smear, High D range, High S/N
• High resolution and low dark current

Version-4 camera specifications

• LiF/ZnS neutron scintillator, green emission (~520nm)
• Rare-earth ultra-fast x-ray scintillator, green emission (~520nm)
• Front-surfaced Al/SiO₂-mirror; optical flatness 2λ/25mm; reflectivity 94%
• Low light f1.0 lens (order of magnitude brighter than a normal camera)
• Ultra low light sensitivity (0.00001 lux at f1.0), S/N ratio: 52dB
• Exposure selected by hand-held remote controller on 3m or longer cable
• Fast shutter speed: exposures of 0.5, 1, 2, 4, 8, 16 msec
• On-board electronic frame integration system (Slow shutter speed)
• Slow shutter: integration over 1, 2, 4, 8, 16, 32, 64, 128, 256, unlimited frames
• Simultaneous output of composite video & Y/C signals
• Manual gain control (8-38dB) and Gamma correction (3 steps)
• Nominal image resolution ~100 microns (80x60mm compact camera)
• Nominal sensitivity 1 neutron/sec per 100 micron pixel (80x60mm compact camera)
• Reasonable Images with 10s exposures at 10⁴.n.cm^-2.sec^-1
• Suitable for beams of 10⁴ to 10⁹ n.cm^-2.s^-1 (less than 10³ n.cm^-2.s^-1 with cooling)

General Information and FAQs

• The camera sensitivity for a given neutron flux and exposure is inversely proportional to the square of the largest side of the scintillator window.
• The camera thickness depends on the smallest side of the scintillator window.
• The compact camera weighs 525g; the 100mm camera weighs 1 Kg.
• The camera outputs PAL video, accepted by most frame grabbers.
• PAL video allows higher resolution and longer exposures than NTSC.
• The optional TFT display allows the image to be viewed without a computer.
• The included PC-interface is a high speed USB-2 frame grabber.
• The camera comes with a 12v DC regulated supply to EU or US specs.
• It should be possible to use the camera in a vacuum. You would need vacuum connectors for the cables and a heat sink to dissipate 3 watts.
• Cameras use aluminium boxes and screws to reduce activation.
• The CCD unit, outside the beam, should be shielded from neutrons and x-rays.
• The scintillator will eventually be destroyed if left permanently in the beam (replacements are available).
• The light output will fall by 30% after an integrated flux of 10¹⁴.n.cm^-2
  (more than 100 days in a constant 10⁷.n.cm^-2.s^-1 neutron beam).
• The scintillator will also detect X-rays and gammas, but we see these only as isolated pixel flashes in the neutron beam.
• With long exposures a few noisy pixels will be seen, but can be eliminated with the "salt and pepper" filter or the optional Peltier cooler.
• With very long exposures (minutes) at maximum gain and gamma for very low fluxes (<10³ n.cm^-2.s^-1), a diffuse noise patch may be seen in one corner of the image. This is low-level infra-red radiation from the amplifiers at the edge of the CCD. A solution is to subtract a "dark field" image obtained under the same conditions with the neutron beam off, or use the ImageJ Process/Subtract Background.
• Testing the camera without neutrons should show only a few isolated bright pixels for very long exposures (10+ sec). If you remove the CCD unit and shine a light through the lens into the camera box, you can activate the whole scintillator, which you can then see for some minutes after you replace the CCD unit.