A customised atmospheric pressure plasma jet for conservation requirements

In the last years atmospheric plasma has gained an increasing interest in the field of Cultural Heritage. Isolated experimentations that yet generated interesting results have drawn the attention of a wider community working on coating removal, oxide reduction and sterilization applications. Thanks to this growing multidisciplinary interest, the EU funded in 2011 the PANNA project, which includes the atmospheric plasma as a novel cleaning tool for cultural heritage. Plasma cleaning has some advantages compared to standard techniques because it avoids the use of solvents, it is contactless and differently from laser it works through a surface chemical action and not with mechanical shock or local heating. Moreover, atmospheric plasma has already shown good results in reducing mode for the conversion of corroded metal surface layers and in oxidation mode for biological cleaning and organic layer removal. In order to fulfil the Cultural Heritage requirements a novel plasma torch has been developed with a new design which allows to overcome the actual limits of commercial atmospheric plasma devices. The new device permits fast and effective treatments at temperatures lower than 50 °C, even at room temperature, without any electrode material deposition. These performances will be presented in relation to the removal of epoxy coatings and daguerreotype cleaning as examples.