Relative and absolute light output of the J-PET scintillators as a function of the WLS concentration.

<p>Relative and absolute light output of the J-PET scintillators as a function of the WLS concentration.</p

Emission spectra of BC-420, J-PET scintillator and scintillators’ absorption coefficient <i>μ</i>_<i>eff</i> [37, 38].

<p>The emission spectra are normalized in amplitude.</p

Averaged signals from photomultiplier connected to BC-420 scintillator (top) and to J-PET scintillator (bottom).

<p>Red dashed line indicates result of fitting a function given by the sum of Formulas <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186728#pone.0186728.e013" target="_blank">(2)</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186728#pone.0186728.e014" target="_blank">(3)</a>. Signals were normalized to the amplitude equal to 1V.</p

Charge spectra measured with the J-PET and BC-420 scintillator.

<p>PM1, PM2, PM3, PM4 used in the legend denote photomultipliers indicated in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186728#pone.0186728.g003" target="_blank">Fig 3</a>. In the left side charge spectra of the J-PET scintillator (0.05J-PET or 0.5J-PET) measured with photomultipliers PM1 and PM2 are compared to the spectra of BC-420 scintillator measured with the same pair of photomultipliers. The number in the name of the J-PET scintillator indicates the concentration of WLS in ‰. In the right side spectra of the J-PET scintillators are compared to spectra of BC-420 measured with the same pair of photomultipliers: PM3 and PM4. The difference between the spectra for the low values of charge are due to the fact that PM1 and PM3 were used in the trigger. The differences at large charge (at the Compton edge) are due to the differences in the light yield.</p

Thermal schedule for scintillator polymerization.

<p>Thermal schedule for scintillator polymerization.</p

Average signals measured with detectors consisting of the BC-420 or the J-PET scintillators and Hamamatsu R9800 photomultiplier.

<p>The shown shapes result from averaging of 10⁵ signals using method described in references [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186728#pone.0186728.ref017" target="_blank">17</a>]. Signals were normalized to the amplitude equal to 1V.</p

Relative and absolute light output of the J-PET plastic scintillators.

<p>Relative and absolute light output of the J-PET plastic scintillators.</p

Emission spectra of scintillators and quantum efficieny of photomultipliers.

<p>Emission spectra of the J-PET (solid line) and BC-420 (dashed line) scintillators [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186728#pone.0186728.ref022" target="_blank">22</a>] superimposed on the quantum efficiency dependence on photons wavelength for typical vacuum tube photomultiplier with bialcali window (dotted line) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186728#pone.0186728.ref035" target="_blank">35</a>] and silicon photomultipliers (dashed-dotted line) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186728#pone.0186728.ref035" target="_blank">35</a>]. Maximum of emission for BC-420 scintillator is placed at wavelength of 393 nm while the maximum of the J-PET scintillator at 403 nm. The emission spectra are normalized in amplitude.</p

Properties of J-PET scintillator and of exemplary plastic scintillators manufactured by Saint Gobain [22].

<p>Properties of J-PET scintillator and of exemplary plastic scintillators manufactured by Saint Gobain [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186728#pone.0186728.ref022" target="_blank">22</a>].</p

J-PET detection modules: A pair and a single layer.

<p>(A) Left panel: scheme of the pair of J-PET detection modules. Such pair constitutes a simplest detection unit capable of registration both collinearly propagating quanta resulting from electron—positron annihilation. Times of light signals arrivals to photomultipliers are denoted as: —to left upper photomultiplier, —to right upper photomultiplier, —to left lower photomultiplier, —to right lower photomultiplier. Red dot indicates a place of annihilation, Δ<i>z</i> denotes the distance between the point of interaction in scintillator and the center of the strip, Δ<i>LOR</i> denotes the position of annihilation along the line-of-response between two strips with respect to the centre of LOR. Both Δ<i>z</i> and Δ<i>LOR</i> are determined based on the measured times , , , . (B) Right panel: schematic visualization of an example of a single detection layer of the J-PET detector. Each scintillator strip is aligned axially and read out at two ends by photomultipliers.</p