Background photons can cloud your gamma spectrum and make life a little harder and so it becomes important to remove them. In order to remove them, I have written a small program in Java which does this. This program comes with no warranties and should be used AT YOUR OWN RISK. If it causes you problems, I apologize but you use the program at your own risk. I am working on a better version with a nice graphical user interface and additional features.
Download zip file and extract to some desired location, perhaps c:\polihelper\.
Ensure Java Runtime Environment is at least Version 6 Update 30 or later (see how to check at http://ww2.valdosta.edu/vista/java_checkversion.shtml)
Take a background spectrum (without sample) for a period of time, perhaps 30 minutes.
Take a spectrum of the sample for the same period of time.
Use place the spectrum files in the same place as the program and run the program
Example: polihelper sample-spectrum.spe background-spectrum.spe cleaned-sample-spectrum.spe
Now, merely open the new file using Poli Identify and enjoy your cleaned spectrum!
The Current Build: http://anti-proton.com/polihelper.zip