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Fiber-Optic-Taper CCD Cameras for X-ray Crystallography
Application #1:
Percent of X-ray photons detected Wide Angle Scattering of Monochromatic X-Rays From Complex Crystals such as Proteins. Rotating anode sources are used in a laboratory with either copper (8 keV) or Molybdenum (17 keV) anodes. Alternatively, synchrotron sources can provide high brilliance illumination, typically in the range 10-12 keV. Detailed spot patterns must be digitized at small increments of crystal rotation (i.e. "phi-slicing"). Spots are typically 100-200 microns FWHM, with an approximately exponential spot brightness histogram. This leads to a requirement for a large area detector, high dynamic range, and low noise readout. 12.4 100 90 80 70 60 50 40 30 20 10 0 1 Gadolinium L-edge 7.24 keV

SCX-TE/CCD-1242E

Photon Wavelength (е) 1.24

0.124

Gadolinium K-edge 50.2 keV

Special Applications

10 Photon energy, keV X-ray quantum efficiency, including GdOS phosphor (25 mg/cm2) and Be window absorption Photon Wavelength (е) 1.24

100

Application #2:
Small Angle Scattering from Larger Scale Morphological Domains in Materials (e.g. aligned regions in polymers, and grains or precipitates in metals). The X-Ray sources used are similar to those for the first application (above). Patterns may be more diffuse than wide angle scattering. Relatively rapid imaging may be required to capture phase or morphology changes during thermal or mechanical processing. Electrons per X-ray photon detected

12.4 100

0.124

10

Detection Requirements for These Applications
Typically 16 bits dynamic range, large detection area, and low noise.

1

X-Ray Detection Mechanism Used in This Camera Design
X-Rays are absorbed by a phosphor screen (GdOS:Tb) which emits visible light (500550 nm). This is coupled to the CCD by a reducing fused fiber optic taper. The CCD detects one or more visible photons per Xray photon absorbed.

1

10 Photon energy keV

100

Detection gain with a 2.3:1 taper ratio. Data in both of the above graphs are representative. Other phosphor screens can be provided with different performance, at a tradeoff of resolution. with a thin (0.5 mm) Beryllium window to admit X-rays. This configuration allows efficient cooling without condensation on the phosphor. Tapers up to 115 mm (full circular aperture viewable) are supported, for maximum field of view. Smaller taper ratios are also supported, for higher sensitivity. The former are best Princeton Instruments matched to high brilliance sources and the latter to weaker sources and smaller crystals .

Camera Configuration
The phosphor is attached to the front face of the taper. The phosphor, taper, and CCD are all enclosed in a vacuum chamber, 80

Shuttering and Synchronization
Electrical timing signals are available from the camera controller, for synchronization with a customer provided X-ray shutter. Tel: 609-587-9797


The CCD can be continuously cleared of dark charge while waiting for an exposure to begin.

Special Configurations
On a special order basis, custom fiber optic taper configurations can be provided, including configurations to support backscatter imaging or simultaneous wide and small angle scattering (with two cameras). Frame transfer operation can also be provided, for higher frame rates. Configurations with multiple CCD/taper assemblies can also be provided, on a special order basis. Contact your regional Princeton Instruments salesperson for the latest information concerning these and other options for fiber-optic taper cameras used in X-ray crystallography applications.

Performance Specifications
CCD Array: EEV CCD-05-30 Grade 1; MPP (lowest dark current), or non-MPP (largest well capacity) 1152 в 1242 pixels 22.5 в 22.5 µm pixels (at the CCD) 25.9 в 27.5 mm (at the CCD) Without binning, 500,000 electrons for non-MPP device, 300,000 electrons for MPP (AIMO) device; With 2 в 2 binning, 1,200,000 electrons, MPP or non-MPP 4-8 electrons at 50 kHz (i.e. <1 X-ray photon at 8 electrons/X-photon) 15 electrons at 150 kHz -30°C with water circulation In this design the CCD itself is not exposed to X-rays, and so is therefore not at risk to X-ray damage 43 or fewer point defects; 6 or fewer cluster defects; 2 or fewer partial column defects or 1 or fewer full column defects; Higher and lower grade devices are available on request, please call the factory for details Model 1, 115 mm diameter, circular view; Model 2, 65 в 65 mm square view (90 mm diameter taper, corners of CCD may be underilluminated) 4.6:1 for Model 1; 2.5:1 for Model 2 5% standard 25 mm diameter for Model 1; 25 в 25 mm for Model 2 Includes bow, pincushion, and barrell distortion. Measurement is the deviation from straight of a straight line after passing through the taper. Calculated as a percentage of the taper diameter at the end the measurement is made on. 2% for both models. This type of distortion is where a straight continuous line at one end of the taper becomes a discontinuous line at the other end; Shear magnitude (lateral displacement) 10-25 µm; Shear length, 60 µm; Maximum number allowed, 15; Larger shear distortions not allowed These are areas with light transmission less than 70% of average; Blemishes less than 75 µm at the small end of the taper, < 1% of the imaging area; Blemishes 75-150 µm, 10; Blemishes greater than 150 µm, none; Chicken wire pattern, 3-6 mm length, 5, none greater than 6 mm Princeton Instruments 81

Special Applications

Format:

Full Well Capacity:

Read Noise: Cooling: CCD Damage Protection: CCD Blemish Specifications:

Taper Field of View:

Taper Reduction Factor: Taper EMA: Taper Dimensions at CCD: Taper Gross Distortion:

Taper Shear Distortion:

Taper Defects:

Fax: 609-587-1970