Carbon 14 measurements, which allow a relic to be dated, show that the tunic in Santa Croce dates back to some time between the late 13th century and late 14th century and thus could not have belonged to the “Poor Man of Assisi”, who died in 1226. These and other discovers were made possible through the analysis of the relics with a tandem particle accelerator, which was performed by the Laboratory of Nuclear Techniques for Cultural Heritage (LABEC) of the INFN of Florence.
The results of the study were presented in Florence at the European Conference on Accelerators in Applied Research and Technology (ECAART) and will be published in the volume “L’eredità del Padre: le reliquie di San Francesco a Cortona” (which will be released in a few weeks by Edizioni Messaggero di Sant’Antonio). The volume will include the complete results of an interdisciplinary investigation which included both scientific and humanist research and which was promoted by the Tuscany Province Chapter of the Franciscan Order “Friars Minor Conventual”.
The analyses were conducted with a radiocarbon method, measuring the radiocarbon using Accelerator Mass Spectrometry (AMS). From each tunic, researchers took from 5 to 7 samples of fabric, each of which was smaller than one square centimetre and weighed around 10 milligrams. Multiple samples were taken to avoid doubts or ambiguities (due to, for example, the presence of patches that were added to the tunic at a later time), thus increasing the analysis’ validity.
Each sample of wool was then treated so as to extract only the carbon, obtaining a small graphite pellet weighing about 0.8 milligrams. The pellet was then placed in the accelerator’s chamber, where it was exposed to a beam of cesium ions, “scratching” the pellet’s surface and extracting carbon isotopes 12, 13, and 14. The accelerator used by the INFN separately measured the quantity of the three isotopes. Relics are dated by calculating the ratio of carbon 14 to carbon 12, the quantities of which are “counted” in the accelerator’s detectors. Both great delicacy and exceptional sensitivity are required for taking these measurements; in fact, the ratio of carbon 14 to carbon 12 is only around one to one trillion, or even lower.
The analysis of the tunic preserved in the Basilica of Santa Croce in Florence showed that it dates back to a period between the end of the 1200s and the end of the 1300s, revealing that it was made at least 80 years after Saint Francis’ death and thus could not have belonged to him.
By contrast, the dates of all of the fragments taken from the tunic in the church in Cortona coincide with the period of Saint Francis’ life (the average results show that the tunic was made between 1155 and 1225). The tunic is one of three Franciscan relics, which also include a finely embroidered cushion and a book of gospels believed to have been brought to Cortona by Friar Elia, Saint Francis’ first successor as leader of the order.
LABEC researchers also analysed the composition of the precious metal thread used to embroider the cover of the cushion on which the Saint’s head was placed upon his death, and they used the carbon 14 method to date the fabric of the cushion itself. Moreover, the book of gospels was subjected to in-depth codicological and paleographic investigations by researchers at the University of Siena. Based on both the scientific evidence and humanistic research, the cushion and the book of gospels were also found to date back to the period in which Saint Francis lived.
Working in collaboration with LABEC of the INFN of Florence were the Soprintendenza per i Beni Architettonici e per il Paesaggio, per il Patrimonio Storico, Artistico ed Etnoantropologico of the Arezzo Province, the University of Siena, and the Centro Interdipartimentale di Studi sui Beni Librari e Archivistici of Arezzo.
Eleonora Cossi | alfa
New manifestation of magnetic monopoles discovered
08.12.2017 | Institute of Science and Technology Austria
NASA's SuperTIGER balloon flies again to study heavy cosmic particles
07.12.2017 | NASA/Goddard Space Flight Center
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications
Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...
Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.
The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...
Transistors based on carbon nanostructures: what sounds like a futuristic dream could be reality in just a few years' time. An international research team working with Empa has now succeeded in producing nanotransistors from graphene ribbons that are only a few atoms wide, as reported in the current issue of the trade journal "Nature Communications."
Graphene ribbons that are only a few atoms wide, so-called graphene nanoribbons, have special electrical properties that make them promising candidates for the...
08.12.2017 | Event News
07.12.2017 | Event News
05.12.2017 | Event News
08.12.2017 | Life Sciences
08.12.2017 | Information Technology
08.12.2017 | Information Technology