Positron Research Group -|-|- St Olaf College, Northfield, MN, USA


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Positron Research Group
Science Center 155
1520 St. Olaf Avenue
Northfield, MN 55057

Dr. Jason Engbrecht
507-646-3968 FAX


Anna Legard '08

Dan Endean '09

David Green '09





The energy and lifetime data are collected by a Labview program we created called "The Interface." The program takes in all data and sorts out coincidence data as tagged by the coincidence circuit.

Screen shot of The Interface: The graphs labeled with green are the acquistion energy and total energy graphs. The graphs labeled with blue are the acquisition lifetime and total lifetime graphs. The graphs labeled with red are the coincidence data insensity and total coincidence lifetime plots.

The Interface then saves the coincidence data in a format that can be read by the analysis software. The coincidence energy and lifetime data are saved in a 2D array. An example of this array is shown in the following image:

3D plot of coincidence data: We are interested in how the width of the energy peak changes with lifetime. Due to doppler broadening, the energy peaks around 300 ns are narrower than the energy peaks around 120 ns. This is due to doppler broadening. This will be further discussed in the analysis section.

To prepare the data for analysis, we use another Labview program we created that reads in the 2D coincidence data array and splits the lifetime channels into groups. The energy data in each lifetime channel is summed together with all the energy data in the other lifetime channels in its group, thereby giving us a better set of data from which to determine the actual energy peak for a given range of channels. The data in the groups of lifetime channels is saved in a format that can be read by the analysis software.


Lets analyze the data! --->