scintillator:
(in production for Lightwave 09 festival, Trinity College Dublin.
Opening weekend is Jan. 24th.)
 
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What makes physics scintillating?

Scintillator is an interactive sculpture made from fluorescent scintillator bars and wavelength shifting fibers. Your interaction will make the sculpture shift colour. The sculpture’s composition is inspired by tetrahedral forms, the Platonic solids and Kepler’s diagrams of planetary systems, investigating the underlying structures of nature. Scintillator brings you materials that are frequently used in many modern physics experiments to detect elusive subatomic particles and high-energy electromagnetic radiation such as gamma rays or x-rays at a very high precision, and convert it to visible light which can be detected and measured.

What IS it, exactly?

All scintillators fluoresce
but not all fluorescent compounds are scintillators. It is very common to see fluorescent plastics sold in everyday items, but a fluorescent scintillator is very specific: it is produced with compounds (dopants) specifically to absorb the energy from charged subatomic particles. Once the material absorbs this energy, it is re-emitted as a flash of light, to be detected by photomultipliers.

Scintillator detection systems are often coupled with a wavelength-shifting material, which will shift the wavelength(color) of the emitted flash of light to another wavelength that is more easily detected by a photomultiplier tube (PMT), a very sensitive light sensor. The PMT is attached to an electronic amplifier and/or other electronic equipment to count and measure the signals collected in the scintillator.

Wavelength-shifting fiber is not like regular fiber optics. Fiber optics only transmit light from one end to another. In contrast, wavelength-shifting fiber absorbs and then shifts the light that the scintillator collects, to be a specific wavelength that is easier to detect by the photomultiplier. WSF would not be a very good fiber optic. The fluorescing dopants would make it a poor long-distance transmitter (due to attenuation), but a great color-shifting light pipe. Absorbing light through all sides, it then glows, re-emitting it for the PMT to measure.

Scintillator can be in the form of plastics, gases, or liquids. The material from my sculpture in particular is made of polystyrene with a fluorescent added. Each bar has an interior groove that was made from tubing extrusions, resulting in a small hole with a thick wall (similar but inverse of the making of a pipe, which has a thin wall with a large hole). This small groove is for the wavelength-shifting fiber, which is green. In this case it absorbs colors of a 500 nm wavelength, and emits 580.


The purpose of this project is to allude to the past, present, and future of the fascination with and investigation of the underlying structures of nature - referencing history through the form, and the present and future through the material itself. This material, magical and ethereal in its optical qualities, is used in cutting edge experiments at research laboratories including CERN, Fermilab, and the Kamioka Observatory.




fig 1, 2, 3: planetary systam of Johannes Kepler; transformations of Platonic solids; stars, woodcut, Escher's fantasy based on Platonic solids.

below: examples of uv-sensitive scintillator material with varying light. these are prototypes; documentation on final piece forthcoming.