Radiocarbon Dating of Dead Sea Scrolls
Confirm Paleographic Dates

by Donna Kent

Researchers in the Arizona Accelerator Mass Spectrometer (AMS) Laboratory at the University of Arizona have carbon-14 dated samples of the Dead Sea Scrolls, and their results are consistent with ages determined by paleographic research.

A. J. Timothy Jull, Research Scientist, and Douglas J. Donahue, Physics Professor and Director of the AMS facility, measured the amount of radioactive carbon in samples of 18 texts and two textiles from four Qumran Caves and from Nahal Hever, both in the Dead Sea region.

[Image: Photo]

Timothy Jull (left) and Douglas Donahue (right)
discuss their work with Guy Atchley (center) of KGUN news

Carbon-14 dating of milligram samples taken from ragged edges of manuscript margins determined the ages of the scrolls to range from the third century B.C.E. (Before Common Era) to 68 C.E., nearly 2,000 years ago. These dates support earlier paleographic research, which estimated the ages of the scrolls by analyzing the handwriting styles, materials, and formatting of the manuscripts.

The Dead Sea Scrolls were found in jars inside a Qumran cave by young Bedouin shepherds in 1947. Coming from the late Second Temple Period, a time when Jesus of Nazareth lived, they are older than any other surviving biblical manuscripts by almost one thousand years.

The carbon-14 dating technique, developed by Nobel Laureat Willard Frank Libby in 1946, involves measuring the amount of residual radioactive carbon (carbon-14) in a given sample. Carbon-14 has a half-life of 5,730+/-40 years, which means that it takes 5,730 years for half of the radioisotope to disintegrate. Because carbon-14 decays at this constant rate, an estimate of the age of the sample can be made by measuring the amount of its residual radiocarbon.

The AMS Facility features a tandem accelerator mass spectrometer, the first of its kind in the world dedicated exclusively to radiocarbon dating. The accelerator sorts and counts carbon isotopes by mass, enabling researchers to directly count carbon-14 atoms in a sample using only milligrams of the sample to be dated. The laboratory is supported by the National Science Foundation.

To learn more about the Dead Sea Scrolls, see the Library of Congress "Scrolls from the Dead Sea" exhibit.

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