Muons

Published: 20 November 2024

I've just spent a couple of evenings reviewing the code that displays the Muon Counter detail. One of the problems of 'borrowing' other peoples code from the internet is that you may not fully understand it when you need to edit the code. My unhappiness stemmed from the fact that the existing graphs were not really showing me anything, I think this is because the sample window (was 1 minute) was too long and I was losing valuable data in the general noise.

The graphical display code has been re-written to read blocks of data from the CSV file in a 10 second window. I can change this fairly easily in the future as I have actually commented my code.

The revised graphs are now very dense (8640 display points to the graph) and so I am not sure how this will work with a graph width of 1600 pixels.

I may need to rethink.

For information (if you are suffering from insomnia), the process is a broadly as follows:

1. I read a daily block of data from the CW Muon Counter Raspberry Pi.

It looks like this truncated file from 2024-11-17: 

Y,M,D,H,M,S,Event, Ardn_time[ms], ADC[0-1023], SiPM[mV], Deadtime[ms], Temp[C], Name
2024,11,17,00,00,11.869169,4959769, 1032619463, 453, 113.81, 845053568, 23.15,WOBO_MUON_1
2024,11,17,00,00,32.307766,4959770, 1032639923, 496, 144.49, 845057408, 23.15,WOBO_MUON_1
2024,11,17,00,00,33.598346,4959771, 1032641193, 377, 76.28, 845057600, 23.15,WOBO_MUON_1
2024,11,17,00,00,34.803068,4959772, 1032642419, 389, 81.58, 845057984, 23.15,WOBO_MUON_1
2024,11,17,00,00,44.020615,4959773, 1032651632, 415, 95.00, 845059712, 23.15,WOBO_MUON_1
2024,11,17,00,00,46.323831,4959774, 1032653933, 369, 73.42, 845060096, 23.15,WOBO_MUON_1
2024,11,17,00,00,53.045375,4959775, 1032660652, 425, 99.48, 845061440, 23.15,WOBO_MUON_1
2024,11,17,00,01,03.371836,4959776, 1032670971, 728, 431.28, 845063360, 23.15,WOBO_MUON_1
2024,11,17,00,01,15.304950,4959777, 1032682898, 472, 125.87, 845065664, 23.15,WOBO_MUON_1
2024,11,17,00,01,19.087461,4959778, 1032686678, 704, 326.52, 845066432, 23.15,WOBO_MUON_1
2024,11,17,00,01,24.596963,4959779, 1032692184, 450, 114.31, 845067392, 23.15,WOBO_MUON_1
2024,11,17,00,01,29.826490,4959780, 1032697220, 352, 66.89, 845068352, 23.15,WOBO_MUON_1

This is changed from the standard muon data file in that all the commas (its a comma separated file) are written at source by modifying the 'C' code on the CW counters. The commas delimit the tabular columns so that the individual date and time data elements (Y,M,D,H,M,S) can be easily separated for post processing.

To produce the graphs, the only data I need is the time (H,M,S) for each detection.

I then create a separate array and populate the first column of the table with the number of seconds in a day divided by the sample window, currently 10 seconds. 

The array has bounds of 8640 rows x 2 columns.

I simply then parse through the imported csv file, calculate the time in seconds for each event, divide that by the sample window value and populate the array. In the sample above, the three highlighted entries would appear as a count of 3 for the sample window starting at 00:00:30 and ending at 00:00:39.

The array is then passed to a Python module (MatplotLib) to produce the graph.

One problem that I haven't as yet been able to solve is how to set the X axis values from a weird seconds /10 value to simple hours. 

Postscript:

After reviewing the following days results, I could see that many of the bars were not being plotted. 

The program was then modified to plot 8 x 3 hour windows which is much more of a handful but all the data is visible. I have also annotated the maximum daily count below the 'x' axis to help identify any interesting spikes.