EZ-Radioisotope-Decay™ Calculator $4.99

New Version 2.0 January 20 (2024)

EZ-Radioisotope-Decay™ calculates the remaining specific activity of an isotope from the date of manufacture to the date of use in an experiment.


Radioactive decay is what happens when the nucleus is in an excited state and must release energy. Decay cannot occur at any time for 'stable' atoms: there exists a 'binding" energy' which holds the nucleus together. This must be overcome in order for the nucleus to release radiation. However, the nucleus of an atom does not have a set energy, only a probability of having a particular energy to tunnel to a lower energy state. The radioisotope decay law describes the rate at which the material decays. It is an exponential relation between the number of undecayed atoms and time. Mathematically this is described as: NA = NAo * EXP(-k * t)

Where NA is the number of atoms at time t, NAo is the initial number of atoms and k is the decay constant. The half-life of the isotope is defined as the time in which half of the total atoms decay (NA/NAo = 1/2).


1- Muhammad Sagir Abubakar (2019). Radioactive Decay, An Introduction to the concept of Radioactive Decay and Radioactivity in Nuclear Chemistry

2- Claude Amsler (2015). Nuclear and Particle Physics; IOP Publishing Ltd, Bristol, UK

3- Gregory Choppin (2013). Radiochemistry and Nuclear Chemistry; Elsevier; 4th Edition.

Download and Purchase the Software at bottom of page...

This is the main menu where you enter the date the isotope was manufactured and the date of use. The dates MUST be in the format of Day-Month-Year; each containing two digits only. Then enter the specific activity of the isotope in Ci/mmol and the half-life of the isotope in days. Finally, select 'Calculate' to display the specific activity remainingg .

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Alternatively, after entering the dates and specific activity, select a radioisotope from the menu 'Select_Isotope' and press 'Ok'
Finally, select 'Calculate to display the results'.
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Download the latest version of EZ-Radioisotope-Decay™

Download the software zip file to a single folder, Unzip it and then run EZ-Radioisotope-Decay.exe to obtain the registration code to unlock the software on your computer. Then purchase EZ-Radioisotope-Decay using PayPal and email the registration code to us at DrFrank88@gmail.com No Windows installation is required; just drop it into a folder and run.

Note: The generated EZ-Radioisotope-Decay.lic file must reside in the same folder as EZ-Radioisotope-Decay.exe.

Download and unZip the file in a folder (e.g., C:\MyEZ-Radioisotope-Decay\) on a computer you choose to license the software, and then run EZ-Radioisotope-Decay.exe to retrieve the "Registration Code". The lack of formal Windows installation is intentional, as it allows installation without administrative privileges (no dynamic link libraries (DLL) are used) and no network connection. After you've paid for the software using PayPal, email us the Registration Code at drfrank88@gmail.com and we'll send you the Activation Code to enter and fully activate the software. Once activated, do not delete or modify the lic file contained therein as it is required to execute and run the software. We suggest that you make backup copies of both the EZ-Radioisotope-Decay.exe and EZ-Radioisotope-Decay.lic files for future reference. EZ-Radioisotope-Decay is copy-protected to run on one MS Windows 32 or 64-bit computer.
Note: EZ-Radioisotope-Decay.zip has been scanned by Windows Defender.


File size: 396.47 KB

Download the EZ-Radioisotope-Decay ZIP file to your computer and unzip the file in a folder on your computer.


Note: If your browser flags the downloaded zip file with a cautionary warning, you have the option of selecting "keep" to continue the download process. The EZ-Radioisotope-Decay.zip file was scanned with Microsoft Windows Defender and shown not to have any detectable threats. The EZ-Radioisotope-Decay software does not send any information back to us or anyone else, and it does not require a network connection to run. It is a standalone executable file (no DLL files) .

Disclaimer of 'False Positive' virus: EZ-Radioisotope-Decay.exe is an independently distributed program, and as such it may be flagged as a 'false positive' by your antivirus/antimalware software. Therefore, it is advisable to create an exclusion for the EZ-Radioisotope-Decay.exe software to avoid the appearance of 'false positive' errors during execution.