Getting the green light

Ebin Joseph and Brian Leung at Lab 6 work on a substance that could improve the scintillating plastic in particle detectors. Photo: Leticia Shaddix

You may have heard about plastic scintillator in particle detectors. Here, chemists Ebin Joseph (left) and Brian Leung work on an additive that is intended to be mixed into the plastic scintillator to fluoresce at a particular wavelength.

When subatomic particles go through a plastic scintillation detector, energy is deposited in the plastic and is released as flashes of light, which are converted into electrical signals and processed by the detector’s electronics and computers, giving scientists information about the initial particle interaction.

Different additives in the plastic scintillator fluoresce at different wavelengths, and they can be tweaked to yield a product that emits light of a particular wavelength range. For example, your experiment might want to have a plastic scintillator that emits in the wavelength range from 420 to 450 nanometers, which would be observed as blue flashes.

Under the direction of Fermilab scientist Anna Pla-Dalmau, the two chemists are exploring green-light-emitting fluorescent compounds. Joseph, who works at Fermilab as part of the Undergraduate Cooperative Education Program, and Leung, a Fermilab term employee, conduct their research at Lab 6.

Plastic scintillator technology is used widely in high-energy physics and nuclear physics. The MINERvA detector at Fermilab uses plastic scintillator, as did the MINOS detector. The CMS detector at CERN’s Large Hadron Collider also uses the technology.

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