Design and feasibility of active matrix flat panel detector using avalanche amorphous selenium for protein crystallography.
Protein crystallography is the most important technique for resolving the three-dimensional atomic structure of protein by measuring the intensity of its x-ray diffraction pattern. This work proposes a large area flat panel detector for protein crystallography based on direct conversion x-ray detection technique using avalanche amorphous selenium (a-Se) as the high gain photoconductor, and active matrix readout using amorphous silicon (a-Si:H) thin film transistors. The detector employs avalanche multiplication phenomenon of a-Se to make the detector sensitive to each incident x ray. The advantages of the proposed detector over the existing imaging plate and charge coupled device detectors are large area, high dynamic range coupled to single x-ray detection capability, fast readout, high spatial resolution, and inexpensive manufacturing process. The optimal detector design parameters (such as detector size, pixel size, and thickness of a-Se layer), and operating parameters (such as electric field across the a-Se layer) are determined based on the requirements for protein crystallography application. The performance of the detector is evaluated in terms of readout time (<1 s), dynamic range (approximately 10(5)), and sensitivity (approximately 1 x-ray photon), thus validating the detector's efficacy for protein crystallography.
Sultana
Afrin
A
Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada. asultana@venus.uwaterloo.ca
Reznik
Alla
A
Karim
Karim S
KS
Rowlands
J A
JA
D018360:Crystallography, X-Ray / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D011506:Proteins / Q000648:ultrastructure*; D015203:Reproducibility of Results; D012643:Selenium; D012680:Sensitivity and Specificity; D014173:Transistors, Electronic; D014963:X-Ray Intensifying Screens
D011506:Proteins; D012643:Selenium