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Pulse Processing Code

The purpose of this program is to process digital waveforms for the purpose of identifying transient signals appearing within a zero volt signal background with some electronic noise present. The transient signals are caused by radiation (neutron, gamma) interactions in a scintillator, with the emitted light then being detected by a photomultiplier tube (PMT). Noise results from radiation interactions inside the PMT and electronic noise from the detector electronics (e.g. the preamplifier and amplifier).

The program revolves around a database containing waveforms read in from text files containing voltage-time datasets. After the waveforms are read into the database, they are permanently loaded and there is no need to reload them when restarting the program, etc. The waveforms may then be searched for transient events using different search criteria. Two basic search methods are used. In the first, the program looks for some minimum number of sequential like changes in the signal value from one data point to the next, such as five or more sequential positive changes signaling the start of a positive pulse (or the end of a negative one). In the second, the program looks for some minimum number of sequential data point values falling outside (and on the same side) of a window around the average signal value, such as five or more data points greater than the average signal value plus three standard deviations. The user may set various search criteria such as searching for increasing values, decreasing values, values below a window representing background signal, values above such a window; the minimum number of sequential points meeting such a filtering criterion before accepting such points as an event; the minimum amplitude of a possible event before acceptance as an event; and so on. The user may also set criteria regarding which data sets are to be searched and which are not. Events identified using the search criteria can be plotted along with information such as their estimated full-width half-max (FWHM) and peak amplitude and saved to disk as a separate file if desired.

Installation instructions are as follows. Download the file NS_Data.zip and unzip (uncompress) it. It will create a folder named “NS” that contains a number of files and subfolders also containing files. Open the file named “Installation_Instructions.txt” using Notepad, WordPad, MS Word, or some other program capable of reading text files, and then follow the instructions in the file. Once you have followed all of those instructions, the program will be correctly installed on your computer.

The file “How_To_Use.txt” is also included and contains instructions for using the program. An md5 checksum is available here for verifying for the file, if you wish to do that. Finally, a brief description of the layout of the code is given in the MS Word file NS_Data_Layout_Description.doc.

The program is written in Visual Basic for Applications (VBA) and requires MS Excel to run. Authors: Andrew Stephan and David Bowling.