ADVANCED, ENHANCED HEX PROGRAM FOR PIXE

The REX code and subsequent HEX code, originating at Florida State Uni versity, have been extensively used for PIXE spectra fitting. In 1989 we produced a renovated HEX package: WITS-HEX, enabling the original F ortran program to be more accessible to the PIXE community. We moderni sed the user interface by replacing the batch mode of operation with a n integrated, menu-driven environment. We added the ability to edit su pport data files from within the program, provided detailed feedback d uring the fitting process and enhanced spectral plots using high resol ution colour graphics. Our prototype also permitted the inclusion of m any more peaks and absorption coefficients into the element library th an the original HEX. permitting a more extensive element request list to be used during the fitting operation. We have now completed the sec ond phase of the renewal of HEX. The man-machine interface has been up graded to conform to the IBM SAA Common User Access (CUA) standard. Th is eliminated several of the sequential (modal) human-computer dialogu es, replacing them with a single parallel system. The support utility used in WITS-HEX to convert the binary format of spectra captured usin g foreign data acquisition systems has been replaced by code to direct ly access data in ASCII format. The program is now equipped with conte xt-sensitive help and a tutorial. The polynomial background model has been supplemented by a digital filter model, eliminating the associate d instability from the fitting process and other spectral features mod elled. The program has been validated by comparing results with those obtained from the former versions: WITs-HEX and HEX. A demonstration v ersion is available on request for evaluation purposes.