![Page 1: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/1.jpg)
Area Detectors
• Like film can detect position
• Like scintillation detector can measure intensity
• With modern computers can assign hkl from unaligned crystal
• Must convert pixel intensity to intensity by some sort of integration
![Page 2: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/2.jpg)
Image Plates
• Use a phosphor which emits light proportional to x-ray exposure
• Very large dynamic range
• Very low background
• Large input area
• Not a “real time” device
![Page 3: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/3.jpg)
Rigaku r-axis
![Page 4: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/4.jpg)
Image Plate Schematic
![Page 5: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/5.jpg)
How IP works
![Page 6: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/6.jpg)
Small Molecule IP
![Page 7: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/7.jpg)
Schematic
![Page 8: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/8.jpg)
CCD Detector
• The ccd is a standard camera chip
• Need a phosphor to convert x-rays to light
• The ccd pixel is a well that converts photons to electrons and stores them.
• The wells are read out by shifting to special readout wells and using an a-to-d converter
![Page 9: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/9.jpg)
Schematic of a ccd
![Page 10: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/10.jpg)
Noise
• Dark Current—stored electrons from dark exposure
• Can reduce dark current by cooling the ccd.
• Peltier cooling is frequently used
• Readout Noise—from moving pixels to counting registers
• Slower the movement the lower the noise
![Page 11: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/11.jpg)
Size
• More most 1K ccd chips the pixels are too small.
• Use glass taper to expand the face.
• Taper introduces a distortion
• Pixels still to small.
• Binning—fold 4 pixels into 1
• Use large ccd chip 4K
![Page 12: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/12.jpg)
Phosphors
• Thickness is important
• Too thin and x-rays penetrate
• Too thick and emitted photons are re-absorbed
• For Mo radiation phosphor is only about 80% efficient
![Page 13: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/13.jpg)
KappaCCD
Roughly 1K chip12 electrons/photonDark current 0.02electrons/secondRead out at 200kHz—noise about
12electronsPixel size 22.5 x 22.5 micrometersBinned 110 x 110Readout time about 3 seconds
![Page 14: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/14.jpg)
KappaCCD
![Page 15: Area Detectors Like film can detect position Like scintillation detector can measure intensity With modern computers can assign hkl from unaligned crystal](https://reader035.vdocuments.pub/reader035/viewer/2022070308/551c5af7550346a66a8b50fc/html5/thumbnails/15.jpg)
Kappaccd