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Subject: Gamma radiation

Gamma radiation

From: Paolo Francesco Calvini <pacalvin>
Date: Tuesday, February 29, 2000
Patrick Sinco <psinco [at] ans__org> writes

>I am a reporter researching an article on the use of gamma radiation
>to preserve damaged paper documents. I understand that the procedure
>is not widely used in the field of preservation, but would like to
>learn when and how it is used and how well it performs its task....

I published (with L.Santucci) an article in the "Bollettino
dell'Istituto Centrale per la Patologia del Libro (1978-79)", XXXV,
pp.3-10. Since this work is in Italian, I resume the most important

We analyzed both a XVII-century rag paper and a modern
chromatographic paper (Whatman No. 1) subjected to gamma radiations
(0 to 15 Mrad). Even with the minimum doses for disinfection, i.e.
nearly 0.5 Mrad (Studies in Conservation (1979), 24, p.59) the
results were unsatisfactory. With this dose we observed an immediate
decrease of degree of polymerization to 58% of the original value
for the modern paper, and to 85% for the ancient paper, already
strongly degraded. Tensile strength of modern paper remained quite
unaltered as did folding endurance. After artificial aging (6 days
at 80 deg. C and 65% Relative Humidity (R.H.), followed by 3 days
under vacuum and 7 days at 80 deg. C and 65% R.H.), the Whatman
sample subjected to gamma radiations yellowed strongly more than the
reference. Therefore, the results of our tests advise against this
kind of treatment.

Paolo Calvini
Paper Conservation Scientist
Ministero Beni Culturali
Soprintendenza B.A.A. della Liguria
Via Balbi 10 - 16126 Genova

                  Conservation DistList Instance 13:46
                  Distributed: Tuesday, March 7, 2000
                       Message Id: cdl-13-46-007
Received on Tuesday, 29 February, 2000

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