Computer Chemistry Consultancy - XML4Pharma, Schlossbergstr. 20, 78224 Singen, Germany, +49 7731 975044,

Radioactive Decay Calculation Applet

Developed by Computer Chemistry Consultancy

See also our achievements for other projects

This is a tool that we developed as part of a database-driven application for a pharmaceutical company (Radioactive Materials Supply Management). The applet reads information (element, nuclide number, half life) from a simple textfile (Nuclides.txt - in the real application the information comes from a database). Then the following calculations can be performed:

  • Activity at a certain date (whether in the future or in the past)
  • Date at which a certain activity will be (or was) reached
Dates can be entered either manually (format dd-mm-yyyy) or by using the calendar buttons. The very first time you use the calendar it may take some time to load. When entering a date manually, thorough screening for validity is performed. Just try to enter e.g. 29-2-2001 or any other invalid date.

To perform an activity calculation, choose a nuclide, the activity, and the start and ending date. You can also use this to find out what the activity was in the past, e.g. when the sample entered the company.

To perform a calculation of a date at which a certain activity is (or was) reached, use the "Date Calculation" radiobutton. You can then enter a value for the required activiy. You can also use this to find out at which date in the passed the activity was present.

Activities can only have numeric values (try to enter something else and see how it is simply ignored !).

This applet requires you to have the Java-2 plugin installed. If this is not the case, the browser should simply ask you to download and install it from the Sun Microsystems Java website. If you do not have the Java-2 plugin installed, and your browser does not install it automatically, go to the Sun website, go to the "Download Production Release 1.3" section and install the Java-2 plugin following the instructions.
The Java-2 plugin is just a plugin like the Flash-plugin and other plugins you already have. It is perfectly safe and especially useful for intranets.

This tool was designed, constructed, tested and deployed in just somewhat more than 2 working days. It shows how efficiently intranet tools can be developed (we are however specialists in Chemistry and in Java !), using reusable compounds (we have a whole library of them).

The Applet



You can download this applet and use it freely (even on your intranet). If you find any bugs, please let us know.

You need to download the following components, and install them in the same directory

You can also download all these files at once (zip-format)


  • This kind of tools is very useful on (fast) intranets. Java2 enables to develop fast (it is object oriented), leading to robust applications (Java2 is much safer than C++), which can be deployed on the intranet (the user only needs a browser).
  • If you look at the source code of this HTML file, you will see that in the tag describing the Java-2 plugin (the <OBJECT> tag), a reference is made to the web side from where the Java-2 plugin can be loaded and installed. On an intranet of course, you would replace this reference by the one that directs to the place on your intranet from where the plugin can be installed.

A few other applets and applications found on internet (there are many more ...):

other goodies

Jos Aerts, Computer Chemistry Consultancy, August 2001