[Paper Review] 3D Printing of Scintillating Materials

Yonatan Mishnayot, Michael Layani+3 more|arXiv (Cornell University)|Jun 15, 2014

Radiation Detection and Scintillator Technologies3 citations

TL;DR

This study demonstrates, for the first time, the 3D printing of scintillating materials using stereolithography, achieving scintillation efficiency of ~30% relative to commercial EJ-204 scintillators. The method enables complex, custom geometries—such as hollow, mesh-capped cylinders with integrated grooves—unattainable via traditional machining or casting, opening new pathways for tailored radiation detector design.

ABSTRACT

We demonstrate, for the first time, the applicability of 3D printing technique to the manufacture of scintillation detectors. We report of a formulation, usable in stereolithographic printing, that exhibits scintillation efficiency on the order of 30\% of that of commercial polystyrene based scintillators. We discuss the applicability of these techniques and propose future enhancements that will allow tailoring the printed scintillation detectors to various application.

Motivation & Objective

• To develop a 3D-printable scintillating formulation compatible with stereolithographic printing techniques.
• To overcome limitations of conventional scintillator manufacturing—such as long curing times, mold complexity, and geometric constraints—through additive manufacturing.
• To enable the fabrication of intricate detector designs, including hollow, gas-filled, or fiber-integrated structures, that are infeasible with traditional machining or casting.
• To evaluate the scintillation efficiency of printed samples relative to commercial standards like EJ-204.
• To identify and address degradation mechanisms, such as volatile dopant sublimation, for long-term stability.

Proposed method

• Formulated a UV-curable acrylic resin (SR9035) with 0.5 wt% photoinitiator (Lucirin TPO) for stereolithographic printing.
• Doped the resin with scintillating compounds: PPO (1 wt%), POPOP (0.05–0.08 wt%), and naphthalene (1–15 wt%) as a wavelength-shifting activator.
• Printed cylindrical samples (20 mm diameter, 6.3 mm height) using an Asiga Pico Plus 39 printer at two layer thicknesses: 25 µm and 127 µm.
• Used a 15.1 kBq 90Sr source and a photomultiplier tube (Hamamatsu R647) with a 100 mm light guide to measure light output via a CAEN V1720 digitizer.
• Compared light output of printed samples to reference PMMA and EJ-204 scintillator samples in a light-tight environment.
• Printed complex prototypes, including a hollow, mesh-capped cylinder with external grooves for wavelength-shifting fibers, to demonstrate design flexibility.

Experimental results

Research questions

• RQ1 Can stereolithographic 3D printing produce scintillating materials with sufficient light output efficiency for practical radiation detection applications?
• RQ2 Can 3D printing fabricate complex scintillator geometries—such as hollow, gas-filled, or fiber-integrated structures—that are unachievable with traditional machining or casting?
• RQ3 How do layer thickness and interfacial quality in 3D-printed scintillators affect light collection efficiency?
• RQ4 What are the primary causes of scintillation efficiency degradation in printed scintillators, and how can they be mitigated?
• RQ5 Can the 3D printing process be extended to incorporate additional dopants (e.g., Gd, high-Z materials) for enhanced detection of neutral particles like neutrons or photons?

Key findings

• The best-performing printed sample achieved a scintillation efficiency of approximately 30% relative to the commercial EJ-204 scintillator.
• Efficiency increased with higher dopant concentrations: the highest efficiency (28%) was achieved with 15 wt% naphthalene, 1.5 wt% PPO, and 0.08 wt% POPOP.
• Reducing layer thickness from 127 µm to 25 µm improved efficiency from 27% to 28%, suggesting reduced interfacial scattering effects.
• Degradation of scintillation efficiency over time was observed, primarily attributed to sublimation of the volatile naphthalene activator at high concentrations.
• Complex geometries, including a hollow, mesh-capped cylinder with external grooves for wavelength-shifting fibers, were successfully printed, demonstrating design freedom unattainable with conventional methods.
• The study confirms the feasibility of using 3D printing to produce scintillators with tailored geometries and potential for multi-material or graded-dopant printing in future iterations.