Revision: March 3, 2017

Fiber optics have become a regular part of 20th century communication, as familiar to us today as the telegraph wire was a generation before. However the use of fiber optic material goes far beyond its implementation as part of our telephone network. This September, Space Sciences Laboratory scientists will fly a scientific experiment on a high-altitude balloon, like the one pictured below, using fiber optic material to study cosmic rays from space.
 

Cosmic rays are extremely energetic subatomic particles and atomic nuclei that travel nearly at the speed of light. They continually bombard the earth and permeate all of outer space. Because cosmic rays are so energetic, they can be difficult to detect and analyze, and are best studied from vantage points high above the earth's atmosphere or from space. Traditional cosmic ray detectors, like using a large catcher's mitt to catch a 100 mph fastball, have been large, bulky, and massive. However, the rockets and balloons required to take these detectors to high altitudes and to space have both severe weight and size restrictions.

The Scintillating Optical Fiber Calorimeter (SOFCAL) uses fiber optic technology to allow scientists to measure energies and compositions of cosmic rays. The detector consists of ten pairs of 1/2 millimeter-square optical fibers, arranged in an x-y grid formation. When a cosmic ray interacts with the fibers onboard the experiment, they scintillate, or give off pulses of light. This light can then be collected and analyzed to learn about the cosmic ray that produced the light.

On this flight, which will begin from Ft. Sumner, New Mexico, scientists will be interested in cosmic rays that come in the form of both protons and helium nuclei. By investigating these particular components of the cosmic ray spectrum, scientists hope to gain greater insight into both the origins of cosmic rays and the mechanism that accelerates these particles to speeds approaching the speed of light.