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1.1  Key Information

Read this section before you install and start to use ArArCALC. In here key information on the User Policy and Development History of ArArCALC are described, as well as how to get Online Help when you are using the ArArCALC Software.

1.1.1  User Policy

ArArCALC is provided as freeware. This software package may be freely used and distributed amongst different research laboratories or educational institutions. The user is only encouraged to exercise proper referencing to the following paper in Computer and Geosciences when publishing data calculated using this software package:

Koppers, A.A.P.
ArArCALC -- Software for ⁴⁰Ar/³⁹Ar Age Calculations.
Computer and Geosciences 28 (2002) 605-619.

1.1.2  Software and Hardware Requirements

The program ArArCALC is coded in Microsoft Excel 2000/XP/2003 for Windows 95/98/NT/2000/XP. This custom program does not run on Macintosh computers. To run ArArCALC under the Macintosh operating system please install and run VirtualPC first. It is recommended to run ArArCALC on a 2 GHZ computer with at least 512 MB of RAM and a 1024x780 screen resolution.

All program files included with ArArCALC occupy approximately 2.0 MB of total disk space. Typical age calculation workbooks range between 115-500 KB in file size, depending on the number of analyses included.

1.1.3  Online with ArArCALC

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 EarthRef.org 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:

• Multiple input filters can be defined and saved in ArArCALC.
• All input to the dialogboxes is validated.
• Error ellipses are plotted now with higher resolution.
• All data points are now clickable in the isochron diagrams when error ellipses are displayed.
• Older *.AGE files are being updated automatically according to the version of ArArCALC used.
• ArArCALC may now be installed in subdirectories.

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:

• Recalculate button always available to manually force complete recalculation of *.AGE file.
• All diagrams can be copied onto the clipboard as vector-based graphs that can be readily pasted into Adobe Illustrator, Canvas, Corel Draw, and so on.
• All data tables can be sorted in ascending or descending order based on each data category.
• Age summary now also shows ⁴⁰Ar/³⁶Ar intercepts.
• Additional statistics for age plateau diagrams can be viewed in a summary dialogbox.
• Short cut key strokes have been enabled ... such as CTRL S for save and CTRL P for print.
• Exit either closes ArArCALC and Excel together or the user can simply return to Excel.
• Switch to ... option is more automated while saving can be suppressed by holding down the SHIFT key.
• All *.AGE files can be closed without exiting ArArCALC.
• Various layout issues have been resolved.
• Errors in baseline correction (now allowing for negative baselines) and correlation coefficient have been adjusted.
• Procedure blank evolution toolbox added.
• Degassing patterns toolbox added.
• Primary age recalibration toolbox added.

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:

• Negative intensities can be allowed, making age calculations of very young samples statistically more accurate (default is allow).
• The decay corrections for ³⁷Ar and ³⁹Ar can be switched on/off (default is on).
• Corrections for ³⁶Cl can now be made (default is on).
• Blank corrections can be switched off when the intensities have already been blank corrected outside ArArCALC (default is on).
• Help buttons have been placed on all dialogboxes, guiding the user to related help on the ArArCALC website.
• The ArArCALC.log file is now being attached to all age calculation files. This is an important improvement that allows users to send age calculation files back and forth between colleagues, students and other users. Since the attached log file contains all calculation preferences and irradiation definitions, the age calculations are entirely reproducible on other ArArCALC installs, without the users swapping out the ArArCALC.log file all the time. The original log file remains important though, and is now regarded as the master log file in which most of the settings and irradiations of a particular lab are being set and saved. With each new age file, a copy of the master log file gets attached. There is also a function to manually attach the latest version of the Master ArArCALC.log file.
• The tick marking and general layout of the plots have been improved.
• The menu structure has been simplified and more short cut key strokes have been added.
• Lunar age calculations are now possible.
• The user can define the units (volts, amps, counts) in which the intensities are being measured.
• An option has been added to create empty age calculation files in which data can be entered by hand, allowing legacy measurements and data from the literature to be entered and recalculated using ArArCALC .
• Now up to 999 segments or cycli can be defined in the irradiation definitions, while an auto-fill option has been added to speed up the entering of these data.
• The user can now define projects and sub-projects, allowing the user to use branching directory structures to store their age calculation files.
• Added the corrected ⁴⁰Ar/³⁹Ar, ³⁷Ar/³⁹Ar and ³⁶Ar/³⁹Ar to the Additional Parameters table.
• Added zooming capability to enlarge the data tables on screen.
• Saving editable Excel files and printing are now considerably faster.
• The irradiation constants can now be updated when in Edit mode in case edits have been made to the irradiation definitions.
• Data fields such as sample, material, location, analyst (etc.) can now can accommodate longer text entries.

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:

• Bug in the calculation of the total fusion K/Ca ratio has been fixed. These erroneous calculations only affect v2.3 and v2.4.
• In v2.4 the first two data points in the *.AGE calculation files were not preselected. Now all data points are preselected by default.
• Sample names starting with a "0" or ones that look like a "date" are now allowed.
• The display date in the lower-right Info panel in Data Reduction mode now display correctly.
• The J-value now has 8 digits sufficient for < 0.1% age dating projects.
• Blank, air shots and flux monitor measurements are now saved to a local database.
• Air calculations can now be performed and saved in a separate *.AIR calculation file.
• Users are warned about new versions during start up of ArArCALC, if a new version is available on the EarthRef.org server.
• Probability density curves (i.e. ideograms) can be plotted including the ability to perform mixture modeling on up to five different age components. In future versions these plots will be saved to the age calculation files.
• The export to editable Excel files has been made more efficient and the tables are now saved as separate worksheet tabs.
• When importing multiple age files the age plateaus are now plotted in different colors and in an overlay mode.
• The K/Ca profile can now be overlayed on top of the age plateau diagram for easy comparison.
• The irradiation position can now be saved with each age calculation file.
• Irradiation definitions and input filters can now be copied from age calculation files to the Master log file.
• Relative abundance table has been added conform the Renne et al. (2009) "norms" paper in Quaternary Geochronology.
• Error estimates have been added to the Degassing Patterns table and visualization tool.
• Time since irradiation in days has been added to the Additional Parameters table.
• The correction for 36Cl is now using the published algorithms of Renne et al. (2008).
• Mass discrimination corrections now have user option for applying linear, power and exponential laws.
• Mass discrimination corrections can now be done using actual isotopic weights or using integer masses of 40, 39 ... 36.
• Blanks table allows for zero values.
• The "±" symbols and other special symbols now also show correctly on Asian-language computers.
• Input filter now allows for multiple raw data points (readings) per cycle.
• Multicollector data files can now be read by the input filter, such as for the ARGUS or ARGUS VI.
• File watch mode is available for automatically processing newly acquired data files and batch processing of multiple raw data files.
• Age data now can be exported to XML and uploaded to the online GEOCHRON portal.
• User can add Metadata about the age results, standard used, sample, location and laboratory.
• User can request an IGSN number from within ArArCALC which required for uploading to GEOCHRON.
• All age calculations can now be done using traditional age equations or using the new Min et al. (2000) equations allowing for full error propagation and the reporting of full external errors.
• In the data tables double-clicking on a row now includes or excludes data points.
• In the data tables the latest row selection remains highlighted for easy comparison across tables.
• Export for publication now allows for users to pick out the tables and plots to include in the editable Excel files, including a compact mode for placing all tables and diagrams on one page and a special EarthTIME mode for providing an output with a minimum number of recommended tables and plots.
• Export for publication allows you to save age and air shot data in PDF format (if you have Adobe Acrobat installed).
• The Age Recalibration tool has been significantly improved, in particular allowing users to apply the recalibration settings to the underlying age calculation file.

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:

• Export to Excel function has been improved to generate PDFs that have a tighter format.
• The 2-sigma error in the inverse isochron calculation now returns the correct 2-sigma error instead of the 1-sigma error.
• In the *.AIR calculation files the labels in the Additional Ratio table have been fixed to update correctly with the errors being displayed in the table.
• The cut-off MSWD values for deciding whether an isochron is an errorchron and a weighted mean is an error mean are now based on the MSWD > 1 [1,2] x Sqrt(2/f) formulation in Wendt and Carl (1991) for 1-sigma and 2-sigma respectively.
• Better support for users with an international setting on their computers other than English/US.
• Fixed communication problems with IGSN-SESAR webservices.
• Fixed the Additional Ratios table to not give the same six decimal places as the 1-sigma errors listed.
• The relative abundances table is now entirely compatible with Renne et al. (2009) data norm paper, whereby the user can set preferences to display 1-sigma instead of %1-sigma uncertainties and the order can be changed between 40Ar-36Ar and 36Ar-40Ar.
• ARGUS-VI multicollector input filter added.
• Modifier (micro, nano, femto) can be set to generate intensity units as mV and fA.
• Intensities are better handled by displaying units in headers and having a more flexible number formatting allowing for large numbers.
• File Watch mode is improved by handling blanks more gracefully.
• Bug fixed that prevented the page header and footer to be updated while printing or making PDF files.
• Bug fixed in deletion of the wrong input filters.
• Probability of fit has been added for weighted ages and isochron calculations.
• The spreading factor of the data points along the inverse isochron from Jourdan et al. (2009) has been included.
• Procedure blanks are now being stored in and read from local database file.
• Air shot data are now being stored in and read from local database file and can be viewed as a time series.

1.1.5  Future Development Plans

The ArArCALC software is currently being 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 online GEOCHRON database. The first upgrade already was released as Version 2.4 on 22 November 2006, encapsulating numerous upgrades and bug fixes collated over the last four years. On 8 December 2010 a major overhaul of the software was published as Version 2.5 including 34 bug fixes, improvements and upgrades.

Please register at EarthRef.org to stay posted on any ArArCALC news or return to this page to stay on top of any new 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.

Version 3.0

• Custom Charting Tools will be included that allow you to plot your "own" parameters against each other. Although ArArCALC already provides age and K/Ca plateau diagrams, normal and inverse isochrons, and a tool to study the "degassing patterns" for an entire experiment, you might want to plot a variety of different measured and derived parameters. For example, plotting the ³⁷Ar/³⁹Ar and ⁴⁰Ar/³⁹Ar ratios against each other might be very useful when studying multi-mineral samples or whole-rocks, you may also like to plot K/Cl or Cl/Ca plateau diagrams instead of the standard K/Ca diagram, and in some cases you may want to overlay multiple incremental heating experiments within the same age plateau diagram. These improvements (plus others) will also include the ability to export the resulting plots for later use in Microsoft Excel or your favorite drawing program.
• Current data regressions do not weight the errors on the individual data points. Weighted regressions, based on York's equations (York, 1969) for linear fits and on Kyoungwon Kyle Min's (personal communications, 2003) equations for the parabolic fit and the exponential Y_i = a Exp(cX_i) b fit, will allow you to make statistically robust data regressions with more realistic (and slightly larger) error estimates on the intercept values for each measured isotopic mass (40, 39 ... 36).
• The current online help files are already extensive, but far from complete. A User Guide will added to make the use of ArArCALC more transparent and will benefit scientists and students that start to use this software for the first time. It will also allow for a complete description of the programming philosophy and calculation approach, which is necessary to make this software a truly user-friendly and scientific product.

Version 4.0

• Data reduction capabilities for Potassium Salts and Calcium Fluorites will be added allowing you to calculate irradiation induced correction constants. Historically these constants have been measured only occasionally by a handful of laboratories, yet by including this functionality in ArArCALC you can perform these measurements on a more regular basis. Creating a state-of-art database for these measurements will allow for a more robust characterization of irradiation corrections on a reactor-by-reactor basis, and maybe on a irradiation-by-irradiation basis.

See also ...

Contents	ArArCALC
Chapter 1	Using ArArCALC
Section 1.2	Getting Help
Section 1.3	Installing and Removing ArArCALC
Section 1.4	Basic ArArCALC Functionality
Section 1.5	Navigating and Flagging Data Points

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