# Ce- and B-Doped Silica Fibers for Monitoring Low-Energy Proton Beams on a Medical Cyclotron
## 2 Materials and Methods
### Analysis  
To analyze each set of experiments, a Python 3.7.2 script was developed using JetBrains PyCharm Community Edition (2018.3.5 x64) equipped with the XlskvWriter (v1.1.5), numpy (v1.16.2), and pandas (v0.24.1) packages. Foremost, this code aligned the signals collected from the TR13 cyclotron (current on \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Run** & \begin{tabular}{c} **Target** \\ **Material** \\ \end{tabular} & \begin{tabular}{c} **Target** \\ **Position** \\ \end{tabular} & \begin{tabular}{c} **Fiber Position** \\ **on Target \(D\)** \\ \end{tabular} & \
\begin{tabular}{c} **Fiber(s) Used** \\ \end{tabular} &
\begin{tabular}{c} **Conditions** \\ \end{tabular} \\ \hline
1A & Solid T1 & \(B\) & Inner & Ce-600 & Up to 10 \(\upmu\)A, no beam steering \\
1B & Water & \(A\) & Inner & Ce-600 & Up to 20 \(\upmu\)A, no beam steering \\
1C & \({}^{18}\)O gas & \(D\) & Inner & Ce-600 & Up to 25 \(\upmu\)A, no beam steering \\
1D & \({}^{18}\)O gas & \(D\) & Inner & Ce-200 \(\upmu\)B-200 & Up to 25 \(\upmu\)A, no beam steering \\
2A & \({}^{18}\)O gas & \(D\) &
\begin{tabular}{c} All four target \\ quadrants \\ \end{tabular} & Ce-200 \(\upmu\)B-200 & Up to 25 \(\upmu\)A, regular steering \\
2B & Ar/F\({}_{2}\) & \(D\) &
\begin{tabular}{c} All four target \\ quadrants \\ \end{tabular} & Ce-200 \(\upmu\)B-200 & Up to 15 \(\upmu\)As, regular steering \\
3 & \({}^{18}\)O gas & \(D\) & Inner & Ce-200 \(\upmu\)B-200 & Up to 25 \(\upmu\)As, intense steering \\ \hline \hline \end{tabular}
\end{table} 
Table 2: List of Experiments. The fiber(s) were always installed on the gas target in position \(D\), while not only target \(D\) but also \(A\) and \(B\) were irradiated. Only one fiber was read out at the time. Figure 2: (a) Layout of the targets (blue) and fiber (yellow) in the inner position on the target selector (grey) looking upstream. Position \(A\) is housing a natural water target for the \({}^{16}\)O(p,a)\({}^{13}\)N production, position \(B\) is a natural thallium target for the \({}^{203}\)T(p,n)\({}^{203}\)Pb production, position \(C\) holds a target plug, and position \(D\) is an \({}^{18}\)O(p,n)\({}^{18}\)F gas target. (b) Quadrant collimators in front of target port D looking upstream. Each target position has its own quadrant collimator. target and collimators and target pressure) with the signal received from the MPPC module. This was achieved by detecting the first increase in current readings, and the time when a change in the fiber's signal measured a count-per-second reading greater than the average of the first 10 data points plus 1000 counts to be above the standard deviation of the noise level of the background. Additionally, since the MPPC module's sample rate is 10 Hz and the TR13's sample rate is 1 Hz, only one in every 10 fiber signals was used. If two fibers were being alternated during an experiment, the signals were separated by finding the point at which the fiber signal was reported as zero, signifying when a fiber was disengaged. When investigating the effect of beam current on the fiber signal, a linear relationship is expected. Using the data acquired from the TR13 and the fiber, the Pearson correlation coefficients are then calculated in the code between the fiber signal and the collimator and beam currents. This coefficient is a statistical measure that evaluates the strength of a linear relationship where coefficients of \(\pm\)1 signal a perfect positive or negative linear relationship, and of 0 corresponds to no linear relationship. This statistic was selected as our initial analyses revealed a linear relationship between the beam current and target pressure with the fiber signal, see Figure 3. The algorithm also returns the ranges of each beam current in steps of 5 \(\upmu\)A. A signal processing method further detects the regions at which the target selector was moved, classified by points at which a collimator's current is altered beyond a threshold of 0.045 \(\upmu\)A.