1. Introduction to AMS

AccelNET provides a complete AMS data collection system capable of managing data collection for any species of interest. All collected information is logged to disk. The system may be reconfigured by operator command to change ion species.

AMS data logging is comprehensive. Data for every multicup (stable isotope off-axis Faraday cup) are logged in disk files and time stamped with the jumping cycle number in which the measurement was taken. Event data for each detected rare isotope particle is logged and is time stamped with the jumping cycle number and event number within the jumping cycle.

A "setup" file is written containing other information such as the terminal voltage, rare isotope, charge state, etc. for each measurement.

All of the logging files are written in ASCII to make them easy to view, manipulate and input to other programs.

As each cathode measurement is completed, a summary of the measurement is written to a disk file and displayed on the screen.

When the runlist is completed (all cathodes are measured), a summary file is written containing the average currents, rare isotope counts, average ratios, standard deviations etc. for all cathodes in the runlist. Other summary files may be created containing tab separated fields suitable for use by Quattro and Excel.

After all measurements for a list of cathodes have been completed, the datasets gathered may be reanalyzed off line if necessary. Parameters such as the rare isotope gates may be changed and the datasets reprocessed to obtain new summaries.

The summaries are then analyzed to perform normalization, background subtraction and so on.

NEC has written software using the PV-Wave (a data analysis package) language which performs both post measurement functions. NEC calls this software IsoNET.

IsoNET is divided into two programs. One program is used for reanalysis (off line data reduction) of the datasets. It traverses a list of datasets specified by the operator, reevaluates them and writes new summary files.

The second program performs normalization, background subtraction and calculates conventional AMS results and uncertainties.