Seminars Archive

Thu 4 May, at 15:00 - Seminar Room T2


Giuressi, G e Menk,R
nstrumentation and Detectors Laboratory

\"AH401 PICOAMMETER\" - Dario GIURESSI A 20 bit resolution picoammeter for ultra-low currents measurements has been developed by Sincrotrone Trieste. The charge-digitizing converter AH401 performs 20 bit currents measurements from 50pA (resolution 50aA) up to 350nA (resolution 350fA) with integration times from 1 ms to 1 s. The AH401 is light, extremely compact and allows simultaneous 4 channels operations: ideally suited for current measurements of four quadrant BPMs, photodiodes, segmented Ion-Chambers and wherever parallel multichannel currents acquisition is a concern. Its USB2.0 High-Speed link allows very fast data acquisition (currently up to 1 kHz) without significant dead time data transfer. More information about this product could be downloaded from the following web link: \"SEGMENTED IONIZATION CHAMBER\" - Ralph MENK The availability of high intensity micro beams enables time resolved experiments on samples with spatial extensions of some tenths of microns. Final results of these experiments, however, may alter tremendously when fast variation of the beam intensity and spatial fluctuation of the primary beam in vertical and horizontal direction occurs. Thus high-resolution beam position and intensity monitoring becomes essential for these classes of experiments. The high resolution beam position monitor described in this seminar is based on the principle of a segmented ionization chamber and was specifically designed for high flux synchrotron radiation experiments with low or medium high x-ray energies [from 5keV 40 keV] such as x-ray diffraction (protein, SAXS, powder etc), EXAFS, fluorescence and x-ray imaging experiments. Those classes of experiments require precise and simultaneous calibrations of the incident beam intensity in the order of sub- percent for quantitative measurements. The precision of intensity measurements is in the order of 0.3% whilst spatial resolution in the sub micrometer regime can be obtained for sufficient high intensity.

Last Updated on Tuesday, 24 April 2012 15:21