By
Jose Ceja
Arizona Daily Wildcat
Machine can date organic matter up to 50,000 years old
If a machine's worth is measured by its size, then the UA's Accelerator Mass Spetrometer - which has the power to date organic material as old as 50,000 years - is among the most valuable on campus.
The machine, which weighs about 8,000 pounds and is worth $2 million, is used in a process called carbon dating, that could be described as an astronomical game of needle in the haystack.
Atoms of Carbon-14, which are found in all living organisms, are detected among as many as one trillion other atoms and then compared to a decay rate, known as a "half-life" to discern an age.
The half life of carbon is 5,370 years and depending on the amount remaining, the machine can help scientists make an approximation of the age of a given sample.
The new machine is an addition to an older machine, built in 1981, that has been used by scientists to date the Shroud of Turin, once thought to be the burial cloth of Jesus.
Doug Donahue, a UA professor emeritus of physics, has analyzed many of the samples and said that theory was discredited ,and it was proved that the cloth was from the Middle Ages.
Martian meteorites - containing organic material thought to be proof of life on Mars - were also taken to the machine and proved to be mostly matter from Earth.
Most of the funding for the machine - which was built to supplement the aging machine built in 1981 - came from the National Science Foundation, with the UA contributing about a third.
Donahue said the machine has been used for several things - from helping to predict weather patterns such as El Ni–o to verifying the authenticity of paintings.
"It has many, many purposes," he said.
Dana Biddulph, a physics graduate student who has been working with the machine, said about 5,000 samples are analyzed a year for various disciplines all over the world.
Biddulph said the newer machine is being used to date the Dead Sea Scrolls - a collection of written scrolls found in the 1940s - and is confirming estimates that they are about 2,000 years old.
"The demand for this technique seems to be increasing," he said.
