FT COSMIC analysis results
What to expect from the analysis
Data Tables
Below is an image of the summary table of a cosmic run from a hipo file that contains histograms.
Crystals are labeled according the Component number reporting: status (0 means ok while -1 indicates some problems), pedestal value and RMS (in counts), noise (in mV), Occupancy (number of counts in the MIP peak ??) mean value of the charge (in pC), sigma of the charge distribution (in pC), and Chi2 of the exp+Landau fit. Any anomalies (values outside some predefined limits) are highlighted in red. The bottom menu has features not yet implemented in the program and can be ignored. At the end of the analysis the table can be saved as a .txt file using the menu on the top-left corner of the left panel or cleared for a fresh start with a new file/ET data.
Charge < Q >
Pictured above is the panel showing the mean value of charge for two runs. The plot on the left is a run that has channels that did not register cosmic hits for several crystals. This may happen, and should be known that not all crystals will register a hit in every run. The plot on the right is a run in which all the channels registered a hit. The color scale may change based on activity from the cosmic data.
Dead Channels
When looking at the status panel in the calorimeter view, there are channels that are dead or broken that are known. They are consistently in grey, and should be noted when doing analysis. These channels may cause problems with statistics of the crystals, but when looking at the status view, it is just something to note.
For the channels, some are completely dead, and others have lower amplitudes consistently. Below is a list of the dead and malfunctioning channels.
While these colors may not be present in the cosmic status panel, it is important to know what channels are at risk or are known to be malfunctioning from the LED analysis.
Grey channels
- 445 (5,10)
- 379 (-6,7)
- 162 (-3,-4)
Malfunctioning channels
- 51 (-4,-9)
- 145 (3,-5)
Pictured above are the fits that occur in the histogram view for a good and bad channel. While the mean does not vary from an expected value by a lot in the table on the plot, the peak is in an unexpected spot along the x-axis.
Fitting Histograms
When fits are done of the histogram files, some of the fits are done incorrectly.
They will look like the image pictured below.
If this happens in the HIPO file containing the histograms, they need to be changed. For this to be done, select the channel that needs to be refit on the crystal display. To see all channels, select the energy tab, then with the Fit tab at the top of the display use (Fit -> View all). A display pictured below will appear.
With this view, it is easy to see which channels need to be refit. Once a problem channel is selected, use the (Fit -> Adjust fit…) tab, and change the minimum and maximum value in order to better fit the peak of the histogram. The new fit will appear in green instead of blue. To save this value in the table, use the (Table -> Update table) tab, and these values will be automatically updated in the table. The picture below shows the change in the previous and new fit.
”Default” Values
When the crystals have minimal statistics, the values will be set to a default value of 4.000.
If doing further analysis between crystals, this is something important to note.
To combat this, when a channel is set to 4.000, refit the histogram.
Even if the histogram has a fit that looks identical to the fit when the statistics gave a mean value of 4, refitting the histogram will change this value.
Another default value occurs when there is little statistics in the file leading to a value of 0.
For this, these channels are usually dead, so there is nothing that can be done to get this value away from 0.
There may be no statistics from tracks in the crystal, or the crystal may be malfunctioning.