Water-binding solid scintillators: synthesis, emission properties, and tests in 3H and 14C counting

Area of Science:

• Organic Chemistry
• Analytical Chemistry
• Materials Science

Background:

• 2.5-diphenyloxazole (PPO) derivatives are widely used in scintillation detection.
• Developing solid scintillators capable of detecting aqueous samples without prior drying is a significant challenge.

Purpose of the Study:

• To investigate the spectral and fluorescence properties of carbodiimide derivatives of PPO and related compounds.
• To evaluate their suitability as solid scintillators for detecting low-energy beta emitters (3H and 14C).
• To compare chemically water-binding scintillators with absorptive water-binding systems.

Main Methods:

• Synthesis of carbodiimide derivatives of PPO via H2S elimination from thioureas.
• Investigation of fluorescence properties (spectral, time-resolved, quantum yields) in solution and solid state.
• Comparison of PPO carbodiimide systems with PPO/sodium sulfate mixtures for 3H and 14C counting.

Main Results:

• Carbodiimide derivatives of PPO exhibited suitable fluorescence properties for solid scintillator applications.
• These carbodiimides reacted slowly with water under acidic conditions to form ureas.
• Both chemically water-binding (PPO carbodiimides) and absorptive water-binding (PPO/Na2SO4) scintillators successfully detected 3H and 14C decay.

Conclusions:

• Carbodiimide derivatives of PPO are effective chemically water-binding solid scintillators.
• These novel scintillators enable the direct counting of aqueous samples, simplifying the detection process.
• The findings open new avenues for using solid scintillators in the analysis of aqueous samples.