Archie 101: a Lesson in

Ancient Greek

By Manisha Turner

U.S. Department of Energy

ARCHIMEDES

•born in the 3rd century BC

•devised his own numerical system and prefigured integral calculus

•calculated a value for pi and was the first to conceive of infinity

•some of his inventions include a miniature planetarium, pulleys, levers and a common water pump known as an "Archimedes' screw."

THE PALIMPSEST

•174-page copy of Archimedes’ famous treatises, "On Floating Bodies," "The Method of Mechanical Theorems" and the "Stomachion"

•made of goat/ sheep skin

•survived fire, water, acid, mold, wax, glue and even forgery

PALIMPSESTING A TEXTIn the Middle Ages, a monk needed parchment for a prayer book and recycled the only surviving copy of Archimedes’ work:

•the text was erased with a weak acid (lemon juice)

•next, it was scraped with a pumice stone

•the book was unbound

•the pages were cut down the center

•rotated 90 degrees

•rebound such that the prayers were written perpendicular to the Archimedes text

IMAGING THE TEXT•Multi-spectral imaging

•most of the text recovered with this technique

•uses light of different wavelengths to distinguish between two different texts

20-30% of the text could not be read using this method:

•some of the text is too faint•some covered by mold or other obstacles•four of the pages contain paint forgeries.

X-RAY FLUORESCENCE IMAGING

•At SSRL, we use X-ray fluorescence to evoke the emission of the characteristic x-rays known to iron in the ink.

•When an x-ray beam hits an iron atom the x-ray can be absorbed or scattered.

•If it is absorbed it undergoes a process called the photoelectric effect

•electrons in the inner shells are knocked out, creating electron holes

•electrons from outer shells quickly fill the vacant spots, giving off photons

• each element has a characteristic x-ray because each element has a unique set of energy levels

OBJECTIVES

My project was to improve the scanning procedure.

I had to test and commission a new readout system to:

•speed up readout time

•allow faster scans

•produce well-aligned images

•prevent loss of resolution

To image the palimpsest pages, the parchment is framed and placed in a stage that moves according to the raster method:

ACTUAL SETUP (BL6-2)

40µm

6.4keV

157.48steps/sec

TESTS:•Motor Speed

•two motors used to scan, one for x-direction and one for y-direction

•hypothesized that non-constant speed between acceleration and deceleration may be cause of image misalignment

•Count Time

•time it takes parchment to move between readouts (signals)

•an offset of even a microsecond would cause the pixels to be misaligned and distort the image immensely (image appeared blurred/ stretched)

•Shutter Time

•time period in which the shutter is open during a line scan

•if correct, edges of image are straight and parchment is not exposed to radiation at the beginning/ end of each line scan

Test 1:

Test 1: Stencil

Test 2: Knife Edges

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RESULTS FOR VARIOUS SCAN DISTANCES

*These new values were used to re-image the stencil…

Test 3: Stencil Repeat

Test Archie

•The team from SSRL, the Walters Art Museum in Baltimore and the other collaborating institutes set up the experiment according to the newly found parameters.

• The final scans were completed on Monday, August 7, 2006.

•One of the significant new findings was the complete image of a previously only partly seen diagram in Archimedes’ most important work ‘The Method of Mechanical Theorems’.

One of four parchments containing paint forgery

WHAT HAS BEEN ACCOMPLISHED:•The remainder of the palimpsest was successfully imaged using the new readout system achieved from this experiment.

•The resulting images were sent to ancient Greek experts for translation and made available online at www.archimedespalimpsest.org.

•The total time taken to image one page of parchment was reduced to 12 hours, an improvement by a factor of 5 from the original time of approximately 30 hours!

IN THE FUTURE:•Alternative imaging methods such as confocal imaging

•Scanning for other atoms (like calcium) to make the text more legible for the ancient Greek experts.

REFERENCES[1] “X-Ray fluorescence: Reading tool for ancient manuscripts.” 25 Aug. 2005. http://www.iisc.ernet.in/currsci/aug252005/598.pdf[2] “Placed under X-ray gaze, Archimedes manuscript yields secrets lost to time.” 19 May 2005. http://news-service.stanford.edu/news/2005/may25/archimedes-052505.html[3] “X-Ray Fluorescence Spectroscopy.” 2 Aug. 2005. http://www.amptek.com/technology/radiation_detection.html[4] “Stanford lab reveals hidden writing on ancient parchment; Scientists analyze Archimedes text at accelerator center.” 23 May 2005. http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2005/05/23/MNGQ2CSVND1.DTL&type=science[5]“Brilliant X-rays Reveal Fruits of a Brilliant Mind”, Science, Vol. 313 , page 744 2006

ACKNOWLEDGEMENTS

Uwe Bergmann Martin George Mike Woods