Post by andrewmaclean on Sept 3, 2015 6:22:10 GMT -8
Hey all,
I have been spending some time looking at 152Eu data in run 4238. There are many correlations and mixing ratios to be looked at here and with the statistics we have I chose to start with six. While looking at these I noticed some of the fits were not coming out very well when trying to script them. Looking a bit closer at the projections I could see scatter peaks sitting directly on the edge of the peak for crystals that are close together (i.e. small angles). The best example I have is the 778 keV -> 344 keV -> GS.
The first image shown is a plot of the angle index versus the gamma-ray energy. This has a energy gate cutting on the 778.9 keV gamma-ray. It can be seen that directly on the left edge of the 344 keV gamma-ray there are two strong scatter peaks which are still visible for about the first ten angles (about 60 degrees), then fade away. There are other examples with scatter peaks near by but this one is the worst case laying right on the edge of the desired peak. Even fitting these by hand it is difficult to extract the total counts on the left edge precisely. Moving to the right plot, showing a projection for three different angles you can see where the scatter peaks are and that they diminish. This was done using single crystal methods. Using addback would greatly diminish the size of these scatter peaks and help create a better fit. This is something I am looking into currently but may not finish before the meeting as I have to prepare slides. If I do finish then I will add another post.
I have been spending some time looking at 152Eu data in run 4238. There are many correlations and mixing ratios to be looked at here and with the statistics we have I chose to start with six. While looking at these I noticed some of the fits were not coming out very well when trying to script them. Looking a bit closer at the projections I could see scatter peaks sitting directly on the edge of the peak for crystals that are close together (i.e. small angles). The best example I have is the 778 keV -> 344 keV -> GS.
The first image shown is a plot of the angle index versus the gamma-ray energy. This has a energy gate cutting on the 778.9 keV gamma-ray. It can be seen that directly on the left edge of the 344 keV gamma-ray there are two strong scatter peaks which are still visible for about the first ten angles (about 60 degrees), then fade away. There are other examples with scatter peaks near by but this one is the worst case laying right on the edge of the desired peak. Even fitting these by hand it is difficult to extract the total counts on the left edge precisely. Moving to the right plot, showing a projection for three different angles you can see where the scatter peaks are and that they diminish. This was done using single crystal methods. Using addback would greatly diminish the size of these scatter peaks and help create a better fit. This is something I am looking into currently but may not finish before the meeting as I have to prepare slides. If I do finish then I will add another post.