Sound and light from fractures in scintillators

Area of Science:

• Solid-state physics
• Materials science
• Photonics

Background:

• Particle physics experiments sometimes observe unexpected light emissions.
• Mechanoluminescence, light emission from mechanical stress, is a known phenomenon.
• Inorganic scintillators are materials that emit light when struck by radiation.

Purpose of the Study:

• To investigate light and acoustic emission from inorganic scintillators under mechanical stress.
• To analyze the correlation between light and sound during material fracture.
• To quantify the energy conversion efficiency of mechanoluminescence.

Main Methods:

• Simultaneous measurement of light and acoustic emission.
• Mechanical stress applied to inorganic scintillators (Bi4Ge3O12, CdWO4, ZnWO4).
• Analysis of temporal and amplitude correlations during fracture.
• Utilizing precise energy calibration of Bi4Ge3O12 via radioactive sources.

Main Results:

• Mechanoluminescence was observed in Bi4Ge3O12, CdWO4, and ZnWO4 at room temperature and ambient pressure.
• Temporal and amplitude correlations between light and acoustic signals during fracture were analyzed.
• A lower bound for the elastic energy converted to light was determined to be at least 3×10(-5).

Conclusions:

• Inorganic scintillators exhibit mechanoluminescence under mechanical stress.
• The study provides quantitative data on light-sound correlations during fracture.
• This research offers insights into energy conversion mechanisms in stressed materials.