The MX-Series Tiled CCD Detector Systems
Marresearch is proud to be distributor (outside the Americas) of the world’s most advanced large area CCD-based X-ray detectors manufactured by Rayonix, LLC (formerly Mar USA, Inc.).
The MX Series X-ray detectors offer the largest active areas available, combined with the highest performance available, for protein crystallography and diffraction.
|MX-225||225mm x 225mm||3 x 3 (9 CCDs)||3072 x 3072|
|MX-300||300mm x 300mm||4 x 4 (16 CCDs)||4096 x 4096|
|MX-325||325mm x 325mm||4 x 4 (16 CCDs)||4096 x 4096|
* All specifications are for standard 2x2 binned readout mode unless indicated. 1x1 (unbinned) readout available as a special option, with resolution 6144x6144 for MX-225, 8192x8192 for MX-300 and MX-325.
- SEAMLESS MULTI-ELEMENT CCD TECHNOLOGY
The MX series of detectors use 3 x 3 or 4 x 4 arrays of tiled fiber optic taper elements to make a very large active area for detection. But unlike other multi-element detectors, the images produced have no inactive strips between each of the fiber optic tapers. How is this accomplished? Our innovative design includes tapers that are tiled and machined together as one block, with effectively no gaps between the elements (less than about half of a pixel distance between any neighboring elements). During our calibration process, we measure the amount of signal over the entire detector, and thus are able to correct for the signal incident on every pixel.
- FAST READOUT, LOW NOISE
Every CCD chip is read out through two channels simultaneously. Thus the 3 x 3 MX-225 detector is read out of 18 channels in only 1 second, and the 4 x 4 MX-300 and MX-325 are read out of 32 channels in 1 second at the standard readout resolution. Multiple readout channels allow high speed readout, while maintaining a modest 500kHz pixel readout rate from each channel. Keeping the single channel readout rates slow reduces the read noise.
- HIGH DYNAMIC RANGE
In order to make sensitive comparisons of both low-intensity and high-intensity data possible in a single frame, a detector must have a high dynamic range. Demanding applications like macromolecular crystallography require this. The MX detectors, designed with this in mind, have appropriate gain, full-well capacity, low read noise, and linearity to yield a true 16-bit dynamic range.
- ON-CHIP BINNING
Binning on the chip before readout minimizes noise compared to binning in software, because read noise for a group of pixels is introduced by the read amplifier only once. If binning is done in software, each pixel has read noise introduced separately, and the signals (already made noisy) are summed later. All MX detectors use on-chip binning, enabling the high dynamic range as specified.
- NEW HIGH EFFICIENCY (HE) MODELS AVAILABLE
Rayonix is the first manufacturer of mosaic CCD detectors to make use of thinned, back-illuminated CCD chips. All of the standard MX detectors (3x3 225; 4x4 300 and 325) are available in High Efficiency (HE) versions that use this different CCD chip, but have the same active area and resolution.
Because these back-illuminated CCDs have twice the quantum efficiency of standard front-illuminated chips, and very low noise readout electronics, our HE detectors offer 4X to 8X higher signal to noise ratio at the lowest photon counts. The image at the right displays this rather dramatically—the fact that the back-illuminated chip is nearly black is due to its ability to absorb incident light more efficiently. In addition, these back-illuminated CCDs offer excellent linearity, compared to other high-gain CCD options on the market that we have tested.
The MX HE series were specifically designed with several applications in mind, which require the ability to image and discriminate both weak and strong X-ray signals. These applications include protein crystallography of micro-crystals, low energy X-ray crystallography, small angle X-ray scattering (SAXS), and measurements of other weakly scattering samples, such as protein solutions and thin fibers.
- LOWEST CCD OPERATING TEMPERATURE
The CCDs are operated at a temperature of -70C or below, giving them negligible dark current for any application. The dark current is so low that dark frames of equal integration time as the data frame never need to be recorded; only occasional bias frames of zero integration time are recorded.
- LOW-MAINTENANCE COOLING BY REFRIGERATION
Simple closed-cycle refrigeration, similar to a refrigerator or air-conditioner, is used for cooling: a refrigerant gas expands to cool the cooling head, and then the expanded gas is compressed in an external compressor. No water or other liquids are used for cooling the MX detectors.
- HIGH PRODUCTION STANDARDS
Each of the CCD chips in all MX systems undergoes a series of tests and are selected for low dark current, minimal defects, and high performance. Only fiber optic tapers are selected that have strict quality control for high transmission efficiency, low distortion, and minimal shear effects.
- DETECTOR INTERFACE WITH ONLY ONE COMPUTER WORKSTATION
Images are transferred directly from the detector to the computer workstation with full-frame DMA (Direct Memory Access) via a single fiber optic cable. No intermediary computers or other equipment are necessary.
- PERMANENT FACTORY CALIBRATION
Rayonix scientists understand the methodology of proper detector calibration. Like other Mar detectors, the factory calibration is permanent and routine recalibration is not required.
- Multiple CCD-chips, tiled fiber-optics tapers
Nominal gap between fiber-optics bundles < 1 pixel
- On-chip hardware binning - software selectable
- Phosphor: Gd2O2S:Tb ∼40 μm thick
- Closed-circle refrigeration at -80°C
- CCD sensors are selected for low noise and low number of cosmetic blemishes.
- All defects are correctable and permanently mapped and corrected by our factory calibration procedure. Fiber optic tapers are low Thorium glass with extra mural absorption (EMA) selected for minimal geometric and shear distortions
Control and Data Acquisition System
- Proprietary PCI busmaster DMA Controller with kernel level driver
- Direct transfer of data, in real time, to workstation memory with no involvement of workstation CPU
- Optically isolated digital input for external trigger of shutter and/or readout
- Optically isolated digital output as trigger for external shutter controller
- High current driver circuit for external solenoid shutter
(24V open pulse, 3V hold)
|X-ray sensitive surface||225 x 225 mm²||300 x 300 mm²||325 x 325 mm²|
|Number of CCD-chips||9||16||16|
|Pixels per chip||20482²||20482²||20482²|
|No. of on-chip read-out channels||18||32||32|
|Fiber-optic taper demagnification ratio||2.7 : 1||2.9 : 1||2.9 : 1|
|Software selectable image and pixel sizes||3072² (73 μm)
1536² (146 μm)
|4096² (73 μm)
2048² (146 μm)
|4096² (73 μm)
2048² (158 μm)
|Detective quantum efficiency (DQE) at 8-12 keV||up to 0.8||up to 0.8||up to 0.8|
|Point spread function||FWHM < 100 μm
FW 1% < 300 μm
|FWHM < 100 μm
FW 1% < 300 μm
|FWHM < 100 μm
FW 1% < 300 μm
|Gain (electrons per 12 keV X-ray photon)||6 e‾||6 e¯||6 e¯|
|Read-out noise in standard readout mode||< 10 e¯/pixel||< 10 e¯/pixel||< 10 e¯/pixel|
|Dark current at -70°C||≤ 0.01 e¯/pixel/sec||≤ 0.01 e¯/pixel/sec||≤ 0.01 e¯/pixel/sec|
|Full well capacity for 12 keV photons||60.000 photons/pixel||60.000 photons/pixel||72.000 photons/pixel|
|Dynamic range||16 bits||16 bits||16 bits|
|Physical dimensions of detector head|
|Height x width x depth||46 x 32 x 40 cm||58 x 42 x 43 cm||58 x 42 x 43 cm|
|Weight||< 52 kg||< 115 kg||< 125 kg|
|Physical dimensions of electronics cabinet|
|Height x width x depth||175 x 64 x 64 cm||150 x 64 x 64a cm||150 x 64 x 64a cm|
|Weight||< 215 kg||< 215 kg (x2)||<215 kg (x2)|
- Product brochure (pdf: 270 KB)