2020-445 Liquid Scintillator Containing High-Z Nanoparticles

SUMMARY

UCLA researchers in the Department of Materials Science and Engineering have developed an organic scintillator for identification of gamma radiation. This scintillator has high loading of high-Z nanoparticles without sacrificing optical transparency for better gamma ray detection.

BACKGROUND

Inorganic scintillators are widely used for the detection and identification of gamma radiation due to their high effective atomic number (Z number). However, inorganic scintillators are also costly, difficulty to scale up, and have limited application. Nanocomposite scintillators based on plastic, aromatic hydrocarbons loaded with high-Z nanoparticles modified have been developed as viable alternatives but are vulnerable to phase separation and nanoparticle aggregation. New nanocomposite scintillators are needed to develop economic and high-performance spectroscopic gamma detectors.

INNOVATION

UCLA researchers have developed an organic scintillator with high content, non-toxic high-Z nanoparticles in liquid organic solvent for detection and identification of gamma radiation. The liquid solvent matrix prevents nanoparticle aggregation and monolith phase separation. The organic scintillator can be highly loaded with high-Z nanoparticles without sacrificing optical transparency. Surface ligands of the nanoparticles can be modified to increase solubility. This organic scintillation solution with high loading of high-Z nanoparticles has crucial advantages needed for spectroscopic gamma detectors where high effective atomic number (high-Zeff) is a prerequisite.

POTENTIAL APPLICATIONS

• Gamma radiation identification
• Medical imaging

ADVANTAGES

• High loading factor of high-Z nanoparticles
• High performance of gamma radiation detection
• Low cost
• Easy fabrication

RELATED MATERIALS

• Liu, C. (2017). High-Z Nanoparticle/Polymer Nanocomposites for Gamma-Ray Scintillation Detectors. UCLA. ProQuest ID: Liu_ucla_0031D_15252. Merritt ID: ark:/13030/m5992w9t. https://escholarship.org/uc/item/65s585t2
• Hajagos, T. J., Liu, C., Cherepy, N. J., & Pei, Q. (2018). High‐Z Sensitized Plastic Scintillators: A Review. Advanced Materials, 30(27), 1706956.

STATUS OF DEVELOPMENT

The organic scintillator has been successfully developed and tested to contain 40 wt% nanoparticles with 80% transmittance at the scintillation emission wavelength for bulk volume solutions. The invention also enabled scintillation emission in the blue region of spectrum (around 420 nm), close to the peak position of traditional bialkali PMT’s quantum efficiency. Scintillation light yield is 8500/MeV for 662 keV gamma, with photopeak energy resolution of 15%.