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1.1.4  Development of ArArCALC

ArArCALC was initially developed at the Laboratory of Isotope Geology of the Vrije Universiteit in Amsterdam as part of my Ph.D. thesis. In here I like to acknowledge Jan Wijbrans and Gareth Davies for their supportive roles in designing ArArCALC in the early days. The program is currently being maintained and upgraded at the Scripps Institution of Oceanography in La Jolla and since October 2005 ArArCALC is also sponsored through NSF-EAR Instruments and Facilities to further the development of this data reduction package, to make it useful and available to the international 40Ar/39Ar community, and to make it interoperable with the new (still to be developed) online geochronology databases. As a result, I expect that three major upgrades will be brought out over the coming two years.

Please register at to stay posted on any ArArCALC news or read more on the Future Development Plans. If you have any Requests or Suggestions that will help improve ArArCALC or if you want to share your own Software Code, please contact Anthony Koppers by email.

Early Versions

The first version was programmed already in 1994. Version 1.4 for the Macintosh and version 1.6 for Windows were continuously used as the default data reduction programs at the Vrije Universiteit between 1994 and 1999.

Version 2.0 -- 13 April 1999

First public release of ArArCALC. The help files are not complete yet but they will be added to the downloadable package on short notice. Macintosh support had to be dropped due to significant incompatibilities in the Macintosh version of Microsoft Excel's Visual Basic for Applications.

Version 2.1 -- 17 May 2000

Second public release of ArArCALC. This release goes together with the submission of ArArCALC for publication in Computer and GeoSciences. The key functionality of ArArCALC has not changed dramatically, but the following improvements were added and some shortcomings were removed:

Version 2.2 -- 22 April 2002

Third public release of ArArCALC accompanying publication in Computer and GeoSciences 28 (2002) 605-619. Please Download the ArArCALC paper in PDF format for your own archive and acknowledge the use of ArArCALC by referring to this paper in the Technical Section of your papers. Many improvements were added and some shortcomings were removed. Three highly functional toolboxes have been added (i) to allow for better assessment of the evolution of procedure blanks, (ii) to analyze degassing patterns for all measured argon components, and (iii) to recalibrate the 40Ar/39Ar age calculations all the way back to the primary K-Ar standards. Below follows a short list of the most important updates and changes:

Version 2.3 -- Not Released

This version of ArArCALC was never released and basically encapsulates a series of intermediate versions of the package, mainly used by the developer himself and by a few beta-testing laboratories. All these improvements are being combined and captured in the release of Version 2.4 in November of 2006.

Version 2.4 -- 22 November 2006

Fourth public release of ArArCALC encapsulating numerous upgrades and bug fixes collated over the last four years. This release marks the first of three major upgrades that will be made public over the coming two years under new funding by the EAR Instrument and Facilities program of NSF. Below follows a short list of the most important updates and changes:

Version 2.5 -- 8 December 2010

Fifth public release of ArArCALC and major overhaul of the underlying code and plotting routines. In addition many new features (see below) have been added and many features have been build in making ArArCALC ready for future enhancements. Below follows a list of the 35 most important updates, improvements and changes:

Version 2.5.1 -- Not Released

This intermediate update of ArArCALC was never released and was mainly used by the developer himself to implement a system for bug fixes and small software improvements. It is the intent to release more intermediate versions on a more regular basis.

Version 2.5.2 -- 26 November 2012

First bug fix release of ArArCALC with 14 bug fixes and 4 program enhancements: