Parameters of CCD/CMOS detectors for Neutron or X-ray Imaging

The largest markets are for consumer cameras, industrial or security applications, and biological science, all of which have different requirements to neutron imaging. We use cameras designed for amateur astronomy, where the technical requirements are closest to those needed for neutron imaging (longer, low noise exposures with high dynamic range). We make small cameras for beam alignment, and large cameras for tomographic imaging.

In general, choose the smallest, cheapest camera compatible with your requirements, and eventually trade-up if necessary.

Our Choice of CCD and CMOS detectors.

Detector Slim CCD Slim CMOS Fast CMOS Square CMOS FS60 VS60 CMOS7.1 4/3" CMOS APS-C CMOS FullFrame ICON-L
Type Interline
ICX829		 Pregius
IMX174		 Pregius
IMX432		 Pregius
IMX533		 Interline
ICX694		 Interline
ICX694		 Pregius
IMX428		 Pregius
IMX294		 Pregius
IMX571 		Pregius
IMX455		 Andor
ICON-L
Lens Type
& aperture		 C- Tam f/1.0 C- Tam f/1.2 C- Fuji f/1.4 C- Fuji f/1.4 C- Fuji f/1.4 C- Fuji f/1.4 C- Fuji f/1.4 MFT 35mm f/0.95 MFT 35mm f/0.95 Nikon 50mm f/1.2 Nikon 50mm f/1.2
Typ Optical
Path length		 150mm 150mm 200mm 200-500mm 200-500mm 200-500mm 200-500mm 200-500mm 350-500mm 500mm 500mm
Typ FOV mm
scintillator		 75 x 50 100x100 100x100 100x100 100x100 200x250 200x250 200x250 200x250 200x250 200x250
Pixel size
at FOV		 150µm 85µm 90µm 35-70µm 45-90µm 90µm 90µm 60µm 50µm 30µm 100µm
Resolution pixel 752 x 580 1920x1200 1600x1100 3000x3000 2759x2200 2759x2200 3208x2200 4144x2822 6248x4176 9576x6388 2048x2048
Image diag. mm 8 (1/2") 13 (1/1.2") 17 (1.1") 16 (1.1") 16 (1") 16 (1") 17 (1.1") 23 (4/3") 28 (APS-C) 43 (35mm) 39 (square)
Image area mm 6.46x4.81 11.25x7.03 14.4x9.9 11.3x11.3 12.53x9.99 12.53x9.99 14.4x9.9 19.1x13 23.5x15.7 36 x 24 27.6x27.6
Pixel size µm 8.6 x 8.3 5.86 x 5.86 9.0 x 9.0 3.76x3.76 4.54x4.54 4.54x4.54 4.5 x 4.5 4.6 x 4.6 3.76x3.76 3.75x3.75 13.5x13.5
Quantum effic ~75% ~80% ~72% ~80% ~70% ~70% ~75% ~90% ~90% 90%
Fullwell e- ~40,000 ~30,000 ~80,000 ~50,000 ~20,000 ~20,000 ~20,000 ~66,000 ~50,000 ~50,000 100,000
Read noise e- 10 7 5 3 5 6 3 1.2-7.3 1.0-3.3 1.5-3.5 2.9
Dark c. e-/pix/s <0.1@25°C ~1.0@45°C ~2.5@45°C 0.001@-20°C 0.0004@-10°C 0.0004@-10°C 0.03@-10°C 0.002@-20°C 0.003@0°C 0.003@0°C .0004@-70°C
Peltier Cooling uncooled uncooled uncooled Δ -35 °C or uncooled Δ -27 °C Δ -35 °C Δ -35 °C Δ -35 °C Δ -35 °C Δ -35 °C Δ -70 °C
Max Frame Rate 0.5 41 fps 69 fps 20 fps 0.2 fps 1 fps 30 fps 16 fps 3.5 fps 0.5 1
A/D Readout 16-bits 12-bits 12-bits 14-bits 16-bits 16-bits 12-bits 14-bits 16-bits 16-bits 16-bits
Binning h,v hardware software software hardware hardware hardware hardware hardware hardware hardware hardware
Mount CS-mount C-mount C-mount C-or F-mount C-or F-mount C- or F-mount C- or F-mount M43-mount M43-mount F-mount F-mount
Trigger signals Software Software Software Software Software Software/GPIO Software Software Software Software Software
Interface USB 2.0 USB2/GigE USB3/GigE USB3 USB 2.0/GigE USB 2.0 USB 3.0/GigE USB 3.0 USB 3.0 USB 3.0 Andor
Relative cost
Detect+Lens		 1 1 1.5 1.7-2 4 6 5 3 5 9 50

     The Andor ICON-L is shown for comparison. The collimation and quality of your neutron beam-line will usually be the limiting factor for neutron imaging, not the camera.

Choosing an Imaging Camera - More is not always Better

  • A Lens aperture of f/1.0 transmits x2 as much light as an aperture of f/1.4
  • The Optical path length depends on the required Field-Of-View (FOV), the lens focal length and the detector chip dimensions - see: Qioptiq.
  • The Overall efficiency depends on the ratio of the area of the FOV to the detector, so don't choose a FOV larger than necessary.
  • More pixels means smaller pixels that collect less light. Resolution will be limited by your beam collimation and scintillator thickness, not the detector.
  • Pixel area is proportional to light collection. Combining adjacent small pixels (binning) can be used to emulate large pixels.
  • Quantum Efficiency is just the conversion efficiency, and takes no account of the much more important pixel area.
  • Full Well Capacity is the number of electrons that can be stored in a pixel, and depends on the pixel area.
  • Read Noise is introduced simply by reading out the pixel charge, and is lower for CMOS than for CCD technology.
  • Dark Current is electron noise due to the temperature of the detector, and is lower for CCD than for CMOS technology. CCDs are better for long exposures (>60s).
  • Cooling reduces Dark Current, but with modern detectors little is gained below 0oC because of other noise sources, and long-term radiation damage.
  • Read Times are much shorter for CMOS than for CCD technology, where slow readout is favoured to reduce readout noise.
  • A/D readout determines the Dynamic Dange, and is much higher than the 8-bits (256) intensity levels seen by the human eye.
  • Binning increases the effective area of a pixel, and the light collected. Hardware binning increases the framerate.
  • Bright Lenses are designed with different camera mounts, and different detector-lens (flange) distances.
  • Trigger signals are used to synchronise exposures with sample rotation for tomography. Usually this can be accomplished with software.
  • The camera interface limits the frame rate: USB2 is slow, but long (10-20m) cables can be used. USB3 is faster, but with short (3-5m) cables.
  • The cost depends partly on the technology, but mainly on the market - how many are sold, and what the customer is willing to pay.