A VMEBUS DATA-ACQUISITION AND ANALYSIS SYSTEM FOR THE KFUPM SCANNING NUCLEAR MICROPROBE

This paper describes the VMEbus data acquisition and analysis system at the newly-established scanning nuclear microprobe facility on the Tandetron accelerator at the Energy Research Laboratory of King Fahd University of Petroleum and Minerals. Based on CERN's VALET-Plus VME environment, CAMAC data acquisition hardware, and a Macintosh user interface, the system acquires one energy spectrum and can handle up to 20 energy windows simultaneously. Data is sorted into distribution maps, each 64 x 64 pixels in size. This allows online analysis for multiple elements, thus reducing beam time requirements. Fast display of collected spectra and constructed distribution maps is provided on a color graphics monitor. The VME system synchronizes action with an IBM-compatible 386 computer used by the microbeam apparatus for sample positioning and beam scanning. The system performs other important functions such as calibration, plotting, printing, data storage and retrieval, as well as exporting data to other packages for offline analysis. Details on both the hardware components and the software development are given. Performance data are presented, including typical results obtained during routine runs. User evaluation of the present setup is discussed together with future plans for further improvements.