Fig. 11
a 2-D spectrum of TOT versus energy deposition. b TOT vs energy deposition. Black rectangles correspond to the experimental data. The statistical errors in measuring the values are smaller than the size of symbols due to the large number of entries for the fitted TOT distributions. The red dashed line indicates result of the fit of the function: TOT = A0 + A1 * ln(E dep + A2) + A3 * (ln(E dep + A2))2, with A0 = -2322 ns, A1 = 632.1 ns/keV, A2 = 590.2 keV, and A3 = -42.29 ns/(keV)2. Green dotted line shows the result of another fitting function TOT = A0 ns - A1 * A2\(^{E_{dep}}\) with three parameters where A0 = 42.96 ns, A1 = 53.43 ns, and A2 = 0.997 keV −1. Blue dotted-dashed line represents the model predictions (the “Theoretical model” section) for the total TOT values at four fixed thresholds for the time distribution spectra calculated by using Eq. 3. In framework of J-PET, the light signals are collected on both sides of plastic scintillator as a measure of energy deposition, so in calculating the TOT model, we used twice the value of TOT sum and the value of free parameter N0 is 1.3