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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
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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 TEXT In 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) 157.48steps/sec 6.4keV 40µm
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
RESULTS FOR VARIOUS SCAN DISTANCES . *These new values were used to re-image the stencil…
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’.
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