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Design and feasibility of active matrix flat panel detector using avalanche amorphous selenium for protein crystallography
Author(s) -
Sultana Afrin,
Reznik Alla,
Karim Karim S.,
Rowlands J. A.
Publication year - 2008
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.2975227
Subject(s) - detector , active matrix , optoelectronics , x ray detector , materials science , optics , dynamic range , image resolution , diffraction , wide dynamic range , active layer , physics , thin film transistor , layer (electronics) , nanotechnology
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 ( ∼ 10 5 ) , and sensitivity ( ∼ 1 x‐ray photon), thus validating the detector's efficacy for protein crystallography.