Page 29 - PR 2014 2016 03 Applications of Ionizing Radiations

Applications of Ionizing Radiations | Progress Report 71

Libraries of the Sao Paulo University: Laws Definition of the effective absorbed
School, Communications and Arts School, radiation dose for disinfection
Chemistry School, Integrated Library System of CH and mean remarks
SIBi-USP, City Co. - Planning and Development,
etc. Acting directions to promotion of disin- Ionizing radiation is widely used to eliminate
fection of CH by ionizing radiation involve insects, fungi and bacteria. Desired results
scientific research publications (e.g side-ef- depend on the applied dose or the processing
fects studies); positive diffusion by TV and dose (Gray). The biological effects of gamma
internet videos, etc. and strong interaction rays in living cells are well known and these
programs with restorers and conservation depending on the radiosensitivity, exposition
community supported by national an inter- time, total dose, dose rate, etc. However, some
national organization (e.g. IAEA). Specifically, of the results published in recent years have
two IAEA promotional videos were made in been misinterpreted. From the last studies, it
collaboration of the CTR/IPEN: can be concluded that to eradicate insects in
paper and other cellulosic based materials,
VIDEO 1: relatively low doses are necessary, between
https://www.youtube.com/watch?v=ePiNdzWjoWM
0.5 to 1.0 kGy. Wooden materials usually need
doses among 2-3 kGy to eliminate the larvae.
VIDEO 2:
https://www.youtube.com/watch?v=wvid7KvPPjE Lethal doses to eliminate fungi are significantly
higher than those used for insects. Doses be-
tween 6.0 to 10 kGy can be effective to disinfect
Additionally, the 60 years edition of the IAEA of molds and other fungi in cellulosic based
Bulletin, March 2017 (www.iaea.org/bulletin) materials. Disinfection by radiation processing
contains a special issue titled “Culture Meets is a curative process not preventive without
Nuclear in Brazil” about the impact of the radi- quarantine period or radioactive activation
ation processing of CH and the activities devel- of the constitutive material of the CH objects,
oped by the Multipurpose Gamma Radiation many actions should be taken to avoid recon-
Facility at CTR/IPEN. Since 2013 to the present tamination. Decreasing on polymerization
day, the CH preservation by ionizing radiation degree as a consequence of disinfection of
staff of CTR/IPEN have been actively partici- gamma radiation on cellulose based materi-
pated of consulting and projects supported als is not reflected on macroscopic properties
by IAEA. In 2016, the same team organized (e.g. mechanical resistance) of those materials.
the first training in Latin America related to If applicable, minimization of side-effects of
preservation of CH C7-RLA/0/058-001 “Using
nuclear techniques in support of conservation
and preservation of cultural heritage objects”
at CTR/IPEN. In the same way, maintaining PHOTO: C.L. DE OLIVEIRA/BMA
good irradiation practices is extremely import-
ant. Radiation processing of cultural heritage
needs to be applied in qualified irradiation
facilities as well as the preparation of pre-irra-
diation material protocols related to packaging,
size limitation, etc. and recommendation to Figure 47. Mario de Andrade Public Library disinfection.
Xylophagous insects and fungal colonies in plate culture (yeasts and
cleaning after irradiation. molds) before and after dry cleaning - after irradiation