# Fast-, Light-Cured Scintillating Plastic for 3D-Printing Applications
## 4 Conclusions  
This research developed fast-, light-cured plastic scintillator formulations that can be used for light-based 3D printing using industry-standard 405 nm light. The most promising formulations for creating a clear and hard plastic contained a combined total of EJ-309/DIN and PPO of 30 wt% and a combined total of IBOA and crosslinker of 70 wt% with a IBOA/crosslinker ratio of 70/30. The plastic scintillators were generally solidified within 10-20 s in the 405 nm light from a Formlabs Form Cure. The scintillator with 25-30 wt% of PPO provided the highest radiation detection performance with the light yield up to 83% of that of EJ-276 and up to a PSD FoM of 1.31. We interpret this result to show that it is possible to produce a fast, 405 nm light-cured formulation through this novel approach that compares favorably with EJ-276. The leaching and a hazy film that developed on these high PPO scintillator formulations were eliminated by placing the scintillators in an ethanol bath for 1 h. The overall best-performing scintillator was AFIT225B, which contained 5 wt% DIN, 25 wt% PPO, 21 wt% HDDMA, 0.2 wt% Exalite 416, and 0.1 wt% TPO, did not leach due to the ethanol treatment, and produced a relative light yield of 83% of EJ-276 and PSD FoM of 1.28. Other noted issues, such as surface cracking, haziness, and purpling, were addressed through improved formulations and post-cure heat treatments.  
Future work includes further analysis of the effects of light yield due to curing time and TPO burn-up, a continuation of the formulation development to prevent leaching and/or increase radiation detection performance, and the production of a scintillator using a light-based 3D printer.  
Conceptualization, B.G.F., M.F., P.A.H. and J.E.B.; methodology, B.G.F., M.F., J.J.M. and J.E.B.; software, B.G.F.; validation, B.G.F. and T.W.S.; formal analysis, B.G.F. and T.W.S.; investigation, B.G.F., T.R. and T.W.S.; resources, M.F., P.A.H. and J.E.B.; data curation, B.G.F.; writing--original draft preparation, B.G.F. and J.E.B.; writing--review and editing, M.F. and J.J.M.; visualization, B.G.F.; supervision, J.E.B., M.F. and J.J.M.; project administration, J.E.B. and M.F.; funding acquisition, M.F., P.A.H. and J.E.B. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the Defense Threat Reduction Agency under grant HDTRA1136911, U.S. Department of Energy, Office of Science, Office of High Energy Physics, under Award Number DE-AC05-00 OR22725, and the ORNL Laboratory Directed Research Development Program.  
Not applicable.  
\begin{table}
\begin{tabular}{c c c c c} \hline \multirow{2}{*}{**Scintillator**} & \multicolumn{2}{c}{**Rel. Light Yield [\%]**} & \multicolumn{2}{c}{**PSD FoM**} \\ \cline{2-5}  & **Treated** & **Untreated** & **Treated** & **Untreated** \\ \hline AFIT230 & 74.8 \(\pm\) 1.8 & 72.3 \(\pm\) 1.6 & 1.26 & 1.25 \\ \hline AFIT225 & 83.0 \(\pm\) 2.1 & 82.2 \(\pm\) 2.3 & 1.28 & 1.28 \\ \hline AFIT220 & 77.5 \(\pm\) 1.8 & 77.8 \(\pm\) 2.3 & 1.13 & 1.15 \\ \hline AFIT221 & 75.7 \(\pm\) 1.7 & 74.3 \(\pm\) 1.7 & 1.14 & 1.12 \\ \hline \end{tabular}
\end{table}
Table 1: Radiation detection performance of ethanol-treated and untreated scintillators.  
Data Availability Statement: The radiation performance data from the two level-factorial parameter study (AFIT101-130) and ethanol treatment study (AFIT220-230) of this research are publicly available at [[https://doi.org/10.5281/zenodo.7489982](https://doi.org/10.5281/zenodo.7489982)]([https://doi.org/10.5281/zenodo.7489982](https://doi.org/10.5281/zenodo.7489982)).  
Conflicts of Interest: The authors declare no conflict of interest.