Author/Authors :
D. and Beuville، نويسنده , , E. and Beche، نويسنده , , J.-F. and Cork، نويسنده , , C. and Douence، نويسنده , , V. and Earnest، نويسنده , , T. and Millaud، نويسنده , , J. and Nygren، نويسنده , , D. and Padmore، نويسنده , , H. D. Türko lu، نويسنده , , B. and Zizka، نويسنده , , G. and Datte، نويسنده , , P. and Xuong، نويسنده , , N.-H.، نويسنده ,
Abstract :
A 2D pixel array detector prototype is being designed for static and time resolved protein crystallography. This pixel detector will significantly enhance time resolved laue protein crystallography by two or three orders of magnitude compared to existing sensors such as films or phosphor screens coupled to CCDs. The resolution in time and dynamic range of this type of detector will allow to study structural changes that occur within the protein as a function of time (concurrent readout and acquisition).
ototype consists of an array of 16 × 16 pixels of 150 × 150 μm2 size. The individual pixel processor consists of a low-noise amplifier shaper followed by a differential threshold comparator which provides the counting of individual photons with energies above a programmable threshold. To accommodate the very high rates, above 5 × 108/cm2/s, each pixel processor has a 3 bit pre-scaler which divides the event rate by 8. Overflow from the divider which defines a pseudo fourth bit will generate a readout sequence providing the pixel address. Addresses, generated locally as quantified analog signals, will be used to increment a location in an histogramming memory from which the computerized image of the Laue diagram will be generated.
