LB Feb2017 Se Investigations

Neutron knockout on Se-82

While looking to see if certain lines are indeed selenium within the spectrum, it is worth noting that there are 2 states for Se-81. There is a metastable state with a 57 minute half life and a gamma emission of 103 keV. First I will attempt to show that this metastable state can indeed be seen in the spectrum.

Below is an overlay of 5 plots with different cuts in time.

An attempt to extract the half life from this energy line is outlined below:

1)Within the region of interest, fit the energy line with a Gaussian fit.

2)Once the mean, standard deviation, and the constant have been found, feed those into a custom fit function of the form [3]+[0]*TMath::Gaus(x,[1],[2],1) where [0],[1], and [2] are the constant, mean, and the standard deviation of the original Gaussian fit respectively and [3] is a p0 fit to the background.

3)Once the background is found, set parameter [3] to zero and integrate the custom Gaussian over the whole window of interest.