How can an inexpensive NeutronOptics Camera compete with more expensive detectors?

Choice of CCD and Lens for Different Applications

Big camera companies promote cameras with high frame rates, mega-pixel CMOS and GigE or other fast connections. While such cameras may have some interest for optical imaging, such features have disadvantages for neutron or even x-ray imaging, where intensities and frame rates are much lower. Fast read-out usually means higher noise, more pixels mean smaller pixels that collect less light, and GigE requires special cables and computers.

We choose CCDs, with lower thermal noise than CMOS, especially when they are cooled. We prefer larger pixels, since the area determines the amount of light captured. And if we don't need more than 4 frames/sec, USB2 is sufficient, cheaper and permits cables of up to 30m. But we systematically use 16-bit output, because we need a large range of intensities to detect weak features.

Given these criteria, we offer a large choice of CCD cameras that can be divided into 3 types. Our 752x580 or 1392x1040 pixel slim CCD and compact f/1.0 CS-mount lens (left) is designed for fast imaging with our small cameras. It has the same efficiency as our old video CCD, but with 16-bit output. At the other extreme, our 4008x2672 pixel full-frame 35mm CCD and Nikkor f/1.2 F-mount lens (right) is designed for high resolution imaging.
In between, we offer Sony CCDs of up to 1" with appropriate 1" C-mount lenses (center).


Want to use your own CCD or custom camera ?

If you already have a CCD unit we can build a camera box for it to your own specifications, with or without scintillators and lenses. Our custom laser cut and welded aluminium boxes with B4C light-tight baffles and aluminium screws can be provided with a choice of front-end path lengths to suit the size of your CCD and the focal length of your lens. You simply bolt your CCD to the end of the main box, and swap front-ends and/or lenses to change your Field-of-View and resolution.

For example, a 110x100mm Field-of-View was required with the smallest possible high-resolution camera embedded in shielding behind a pressure cell on the ISIS pulsed source.

We designed a camera using an uncooled 1392x1040 pixel Sony ICX825ALA CCD in a compact housing. Full-frame readout is only 0.5s and multiple exposures can be stacked in real-time to build up an image of the sample in a strongly absorbing environment.

Tell us your specific requirement and we will build a camera to satisfy it.

(Click on the photos to enlarge them).

The mini-iCam 36 mm neutron or x-ray camera

The mini i-Cam is our smallest (and cheapest) x-ray or neutron camera, and uses the slim CCD. It is intended for the alignment of small beams and samples, for example, behind our backscattering Laue camera. It is powered by the USB2 data cable, so is very simple to set up and use.

The i-Cam is only ~190mm long and has 580 or 1040 pixel resolution over an area of 30mm diameter, so with its efficient f/1.0 lens it is also very bright. The scintillator and carbon fibre window can be exchanged, depending on whether x-rays or neutrons are to be imaged.

The mini-iCam can also be supplied without the mirror but with a Pb-glass plate to protect the CCD. The in-beam length is then only ~160mm for an image of 30mm diameter through the carbon fibre window. Details may differ slightly from the photo opposite.

High Resolution Macro Imaging Cameras

Most of our neutron cameras are designed with a nominal resolution of ~100µ, because resolution is determined in practice by beam collimation and scintillator thickness, not by camera optics. With x-ray imaging, much higher beam collimation is possible, especially with synchrotrons, and the flux is orders of magnitude greater, so very thin YAG:Ce or LuAG:Ce single crystal scintillators can be used. Kardjilov has described a simple macro camera using commercial large aperture macro lenses.

We have constructed an inexpensive 1:1 macro imaging camera designed to use the latest Gd2O2S:Tb high resolution neutron/x-ray scintillators now available from RC-TriTec. The photo shows our macro camera optics; without the CCD unit it is 290mm high. With a large f=100mm f/2.8 F-mount macro lens, the FOV is equal to the size of the CCD, and the optical resolution approaches the size of the pixels (<10µ), though the real resolution depends on the scintillator and collimation.

The camera is shown with a carbon fibre x-ray window, but thin aluminium windows are supplied for neutrons, and the C-mount adapter can be unscrewed to take Nikon F-mount cameras up to 35mm full frame.
Our Sony 1" CCD would have a nominal resolution of 5µ.

The C-window unscrews to change the scintillator.

The compact 75x50 mm neutron or x-ray camera

Camera efficiency is proportional to the area of the CCD divided by the imaging area, so our compact 75x50mm camera is also very efficient, again using our slim USB CCD. These small cameras require only the supplied 10m amplified USB cable for power and data acquisition.
  • Sensor Type: Sony EXView ICX829ALA or ICX825ALA
  • Image size: Diagonal 8 mm (1/2") or 11 mm (2/3")
  • Resolution: 752x580 or 1392x1040 pixels
  • Pixel Size: 8.6 x 8.3 µM or 6.45 x 6.45 µM
  • Binning: 2x2 to 8x8 (improved intensity & read-out )
  • High Efficiency: (QE>75% at 500-600nm), low smear
  • Low dark current: (<0.1 e.s ambient), anti-blooming
  • Full Well Capacity: >50,000 electrons (dynamic range)
  • ADC: 16 bit grey scale, optional filtering and distortion
  • Maximum Exposure Length: Unlimited
  • Readout Noise: 10 e- typical value (0ºC)
  • Readout Time: Typically 0.2 sec for full frame via USB2
  • Interface: USB 2.0 High Speed with 10-20m USB cables
  • Power: USB powered, No cooling
  • CCD Unit: 32mm diameter, 72mm height, 50g weight
  • SDK: C++, VB Wrapper, .net Wrapper, ImageJ, LabView

The slim 100x50 mm neutron or x-ray camera

Our popular slim camera is only 44mm thick for a sensitive area of 100x50mm in a 120x120mm box, using our slim USB CCD. It can fit into the small space between the sample environment and the beam stop, and no power is required except for a single 10m USB2 cable for image acquisition. With such a compact camera, a correction may be required for slight barrel distortion.

A larger 100x60mm FOV can be obtained with a 55mm thick box, or a smaller, brighter 75x50mm FOV can be provided with our compact camera. A longer version can also be supplied to eliminate slight barrel distortion.

If required, the digital CCD can be replaced by a video CCD for real-time imaging.

The thin carbon fibre windows used for the x-ray version (left) are much stronger than mylar or aluminium foil, yet are >70% transparent, even for CuKα X-rays (8 KeV).

A choice of x-ray scintillator is available with a thinner scintillator for higher resolution (~100µ) and a thicker scintillator for higher efficiency, especially for harder x-rays, yet still good resolution (~150µ). Top of the page

The improved 100x100mm and 125x125mm cameras

Our new 100x100mm V4. camera is an improvement on the earlier version. In a 165x127x77mm aluminium box it is significantly thinner than our old 100mm camera. It is shown here with our standard slim CCD, but can also be supplied with higher resolution CCDs.

A larger 125x125mm version can be supplied in a 222x146x105mm aluminium box. Again optional high resolution, cooled CCDs can be used.

Other simple custom cameras can be supplied in larger aluminium boxes, such as our 150x120mm camera in a 195x230x100mm box, or our 200x150mm and 250x200mm cameras, but for serious imaging one of our advanced L-shaped cameras with a high resolution cooled CCD is preferable.

Of special interest is our simple 200x100mm camera designed for checking the uniformity of neutron beams transmitted by guides. It is housed in a 250x250mm aluminium box only 75mm thick. The FOV can be increased to 200x125mm using a 100mm thick box (photo below - click to enlarge).

Fast 250x200mm X-ray or Neutron Imaging Camera

Our latest camera has exceptionally low noise, high resolution and fast readout over large areas. We use the new 1 inch Sony ICX694ALG EXview HAD CCD II to give a resolution of 2750x2200 pixels over an area of 250x200mm (90 µm resolution). Dark current is virtually eliminated by thermo-electric cooling by -35C, and high speed readout noise is low. The total noise count in 300s with the cooled CCD is only ~1c/s/pixel (~300 counts in up to 65,536), resulting in excellent dynamic range. The 180mm long front section can easily be removed to change between different neutron and x-ray scintillators. (Detailed Manual)

 

  • Sensor: 1" Sony EXview HAD CCD II
  • Optics: High resolution f/1.4 1" lens
  • Resolution: 2750 x 2200 pixels
  • High sensitivity: (QE~75%), low smear
  • Dark current: 0.002 e/pix/s @-10 °C
  • Cooling: Regulated Peltier ΔT = -35°C
  • Digital Output: 16-bit 65536 levels
  • Readout Speed: 6-12 MPixels/s
  • Binning and Region-of-Interest
  • External Trigger: GPIO synchronisation
  • SDK: C++, VB, .net, ImageJ, LabView
    (Click on the photos to enlarge them)

Other CCD units and lenses can be used with this camera box, by simply changing the length of the front-end section to obtain the desired Field-of-View. For example the Nikkor 50mm f/1.2 lens can be used with the 4/3" 2048x2048 pixel KAI04022 CCD, or the very large 35mm 4008x2672 pixel KAI11002 CCD for highest efficiency and resolution.

Big 400x300mm X-ray or Neutron Imaging Camera

Our biggest camera to date uses the full-frame 35mm Kodak KAI11002 interline CCD with 4008x2672 pixels giving a resolution of ~100 µm over an area of 400x300mm. As usual, the scintillator is in the 200mm interchangeable front section, and the main camera body can accommodate other CCD units and lenses, with the length of the front section adjusted to obtain the desired Field-of-View with the chosen CCD chip dimensions.

  • Sensor: 35mm Kodak KAI11002
  • Optics: Nikkor f/1.2 50mm lens
  • Resolution: 4008 x 2672 pixels
  • High sensitivity: (QE~50%)
  • Dark current: <0.03 at -20 °C
  • Cooling: Regulated ΔT = -38°C
  • Digital Output: 16-bit 65536 levels
  • Readout Speed: 1 MPixels/s
  • Binning and Region-of-Interest
  • Software Trigger
  • SDK: C++, VB, .net, ImageJ, LabView

    Click the photos to enlarge them.
    Note the pencil for scale.


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Laue crystal alignment cameras

We have developed various Laue crystal alignment cameras for x-rays to replace the old Polaroid Laue camera, and similar cameras might be used with a neutron beam. A finely collimated white beam produces a number of "Bragg spots" from a single crystal, and by measuring the positions of these spots the crystal orientation can be determined. Greater precision is obtained with backscattering, but the intensities are much weaker, especially for x-rays because of the scattering "form-factor".

We have recently developed this single Sony 1" CCD backscattering camera, where a fine collimator in the back of the camera directs the beam through a small hole in a mirror and out through the front carbon fibre window. The backscattered diffraction pattern from a single crystal a few cm in front of the window is captured on a scintillator behind the window, and this pattern is reflected by the mirror to the lens-coupled 1" CCD on top.

High Efficiency Photonic Science neutron cameras

CYCLOPS is the latest and largest PhotonicScience neutron Laue camera constructed for ILL. It consists of 16 image-intensified Peltier-cooled CCDs scanning an octagonal scintillator to cover almost complete 4π scattering in real time. Total readout time is only ~1 sec for the complete 7680x2400 array of 170µ pixels as an 8, 12 or 16-bit TIF image. A complete diffraction pattern can be obtained in only a few seconds, making it possible to follow changes in crystal structure as a function of temperature, pressure or magnetic field. Here is a short streaming video illustrating the astonishing power of such a machine, even if at present it is located on a low-flux guide with a 107.n.cm-2.sec-1 white thermal beam.

All these cameras use a white neutron beam, and will work on either reactor or spallation neutron sources. For further details of their application and availability, please contact Alan.Hewat@NeutronOptics.com.
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