The accurate identification of pigments is of principal relevance in the field of cultural heritage conservation and restoration practices. In this preliminary study, a first attempt to set up a procedure for accurate red pigment identification, based on the assessment of the correlations existing between visible reflectance spectrometry (vis-RS) and Raman data, is presented. The proposed approach involved the realization of a library consisting of data acquired on a set of 35 pure red historical pigments supplied by ^©Kremer Pigmente. In particular, vis-RS data, collected through a Konica Minolta CM-2600d spectrophotometer, were registered, together with the position of the Extrema Points (E.P.s) encompassing both the maximum and minimum points of the first derivative of the % spectral reflectance factor (SRF%) curves. Portable Raman spectroscopy measurements were collected by a B&W Tek Inc. portable Raman spectrometer equipped with a 785 nm laser. For each tested pigment, the positions and relative intensities of the characteristic Raman peaks were considered. The library was then tested for the characterization of the red/reddish painted areas of the medieval wall painting located within The Norman Castle of Aci Castello (Catania, Italy), and was shown to be essential for the unambiguous identification of the pigment used. It is worth noting that this study represents the first novel attempt to establish a reliable and efficient methodology for pigment identification, offering promising prospects in reducing uncertainties and ambiguities arising from the application of a single stand-alone approach.

Thermoluminescent dosimeters (TLD) and optically stimulated luminescent dosimeters (OSLD) are practical, accurate, and precise tools for point dosimetry in medical physics applications. The objective of this study is to investigate the luminescence properties—both OSL and TL—of lithium fluoride (LiF) doped with magnesium (Mg), copper (Cu), and phosphorous (P) (LiF: Mg, Cu, P), commercially known as TLD-100H. The goal is to devise a methodological approach for dose measurement that allows for obtaining two independently measured dose values at each irradiation point, thereby improving accuracy and precision. The luminescence properties of TLD-100H were studied using a beta irradiation source (90Sr/90Y) integrated into the TL/OSL DA-15 automated Risø reader. This study identified the ideal experimental conditions for optimal dose evaluation and used them for dosimeter calibration across doses ranging from 0.5 to 4.0 Gy. The results demonstrated that, under optimal measurement parameters, the OSL and residual thermoluminescence (ResTL) signals—correlated to two trap systems within the dosimeter—exhibited high reproducibility, stability over multiple cycles, and high precision and accuracy (≤2%). Specifically, the OSL response showed good linear behavior across the investigated dose range, while the ResTL signal exhibited linear behavior between 0.5 and 2 Gy and sublinear behavior for doses >2 Gy.

Luminescence techniques, especially thermoluminescence (TL) and optically stimulated luminescence (OSL), are essential for dating materials in Cultural Heritage. TL is effective for dating bricks by determining their last heating event, but brick reuse can introduce inaccuracies. OSL enhances accuracy by dating the last light exposure of quartz grains in mortars, a material that is coeval with the construction of the building. However, partial bleaching of quartz grains can lead to overestimated ages. A promising solution involves dating the carbonate fraction of mortars, as calcium carbonate experiences bleaching during mortar preparation. This study investigates the feasibility of isolating signals from quartz and calcite in a composite material. Initially, TL signals for quartz and calcite were characterized separately. A laboratory mixture, comprising 75% quartz and 25% calcite, was irradiated to simulate partial bleaching. TL curve deconvolution revealed distinct peaks: quartz displayed four peaks, while calcite had three, notably lacking a low-temperature peak. The mixed sample exhibited peaks at 527 K, 573 K, 618 K, and 690 K, with the first peak being exclusively quartz, the second primarily quartz with minor calcite, and the third showing contributions from both. Dose-response curves indicated that the quartz peaks aligned with the expected 41.40 Gy dose, and the calcite signal matched 10.40 Gy. This confirms the feasibility of separating TL signals from quartz and calcite in mixed samples, offering a potential method for accurately dating the carbonate fraction in mortars and addressing partial bleaching issues. Future work will focus on optimizing detection parameters and applying this method to historically significant mortars to assess its effectiveness.

Background: Digital tomosynthesis (DTS) is an advanced imaging modality that enhances diagnostic accuracy by offering three-dimensional visualization from two-dimensional projections, which is particularly beneficial in breast and lung imaging. However, this increased imaging capability raises concerns about patient exposure to ionizing radiation. Methods: This study explores the energy and angular dependence of thermoluminescent dosimeters (TLDs), specifically TLD100H, to improve the accuracy of organ dose assessment during DTS. Using a comprehensive experimental approach, organ doses were measured in both DTS and traditional RX modes. Results: The results showed lung doses of approximately 3.21 mGy for the left lung and 3.32 mGy for the right lung during DTS, aligning with the existing literature. In contrast, the RX mode yielded significantly lower lung doses of 0.33 mGy. The heart dose during DTS was measured at 2.81 mGy, corroborating findings from similar studies. Conclusions: These results reinforce the reliability of TLD100H dosimetry in assessing radiation exposure and highlight the need for optimizing imaging protocols to minimize doses. Overall, this study contributes to the ongoing dialogue on enhancing patient safety in diagnostic imaging and advocates for collaboration among medical physicists, radiologists, and technologists to establish best practices.

This paper introduces an innovative sensor utilizing bubbles coated with thermochromic paint, aiming to facilitate temperature measurements in challenging-to-reach locations without the requirement of an external power source. The research conducted is innovative in terms of both methodology and application. The characterization of the thermochromic properties of paints was, in fact, performed using spectroradiometric measurements by selecting a temperature range useful for applications in various fields including preventive conservation. The study encompasses two main objectives: (1) analyzing the color characteristics of thermochromic paint and plastic resin that forms the bubbles, and (2) assessing a temperature sensor comprising a thermochromic paint-coated bubble subjected to temperature variations. The thermochromic paint exhibits reversible color modifications in response to temperature changes, making it an ideal candidate for applications of this nature. The color characterization phase involves measurements using a spectroradiometer to compare the spectral reflectance factor (SRF%) of the colored plastic resin spread on canvas with that of the inflated bubbles. The sensor characterization entails evaluating color changes of the thermochromic paint on the bubble surface with varying temperatures. Experimental results indicate that the combination of a red (R) bubble and blue (B) thermochromic paint produces quantifiable color variations suitable for the proposed applications, whereas the alternative combination under examination, namely a blue bubble and red thermochromic paint, yields less accurate results. Considering that for both thermochromic paints the color change temperature is 35 °C, it is possible to see how, for B bubble with R thermochromic paint, the chromatic coordinates change value: C* = 3.14 ± 0.14 and h = 289.54 ± 11.58 at room temperature, while C* = 2.96 ± 0.12 and h = 304.20 ± 12.17 at 35 °C. The same is true for R bubble with B thermochromic paint where C* = 25.31 ± 1.01 and h* = 285.05 ± 11.40 at room temperature, while C* = 20.87 ± 0.85 and h = 288.37 ± 11.53 at 35 °C. The study demonstrates the potential of the approach and suggests further investigations into reproducibility and expanded color combinations. The results provide a promising basis for future improvements in temperature monitoring with thermochromic bubble sensors.