Proton beam irradiation induces invisible modifications under the surface of painted parchment

Müller, Klaus; Szikszai, Zita; Csepregi, Ákos; Huszánk, Róbert; Kertész, Zsófia; Reiche, Ina

doi:10.1038/s41598-021-02993-7

Cited by 7 publications

(6 citation statements)

References 45 publications

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“…Meanwhile, the width of the crater increases with the deposited charge in all but one instance (T1 spot 1 and 2-but here the depth is informative). These results are in accordance with the SEM cross-section data [31]. Besides the crater formation, a lowered scattering could be observed in the irradiated spot after the short bath in most cases.…”

Section: Optical Coherence Tomographysupporting

confidence: 91%

“…The reversibility and the role of oxygen may point towards the formation of free radicals which were neutralized subsequently, similarly to reversible colour formation in polymers [44]. Nevertheless, deep in the material irreversible colour changes also occurred, as it was seen in cross sections [31], possibly caused by double bond formations and the extended conjugation systems. For the highest dose, the yellow colour was found to be permanently visible even from the surface, without sectioning.…”

Section: Discolouration Occurring In the Parchmentmentioning

confidence: 95%

“…The H 2 O 2 solution was originally used to check the effect of an oxidizing agent on the discoloration caused by the irradiation. However, a gentle stroke with a cotton bud resulted in removing some material from the surface of samples irradiated with higher doses, which was obvious for painted samples (the effect of paint layer is discussed in our previous work [31]). Immersion of the samples in the solution eliminated the additional mechanical interference of stroking.…”

Section: Bath Testmentioning

confidence: 95%

“…The parchment had a relatively heterogeneous thickness of 150-370 µm. Pieces of approximately 2 × 2 cm 2 were cut [31].…”

Section: Parchment Samplesmentioning

confidence: 99%

“…detection limits for the concentration of elements) and safety. In a previous work, we have characterized irradiated parchment samples using imaging methods on cross-sections [31]. Here, we focus on a noninvasive analytical approach to preserve the integrity of the sample and thereby avoid a possible influence of sample preparation on the results.…”

Section: Introductionmentioning

confidence: 99%

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Possible modifications of parchment during ion beam analysis

et al. 2022

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Ion beam analysis (IBA) is an established method to determine the concentration and the distribution of elements in art and archaeological objects. However, especially for organic specimens, caution must be taken to avoid harmful effects. In this work, the possible modification of recent calf parchment samples by proton beam irradiation was investigated applying fluences (given as deposited charge per unit area) both within and beyond the usual analytical practice. Attenuated Total Reflection Fourier Transform Infra-red Spectroscopy (FTIR-ATR) and Optical Coherence Tomography (OCT) were employed to assess changes, inspected from the surface of the samples. Although both techniques are apt to detect alterations of parchment in general, in the case of particles, which deposit the majority of their energy below the surface these techniques could not detect changes at low fluences. However, a simple “bath test” (short immersion in liquid) proved that disintegration within the material had already happened. After the “bath test”, OCT and digital 3D microscopy were used to check the discontinuities in the material, especially for low fluences when the visual inspection might have missed them. Unfortunately, simply monitoring organic objects such as parchment during or after ion beam irradiation, non-destructively, is not sufficient to claim absolute harmlessness, as some studies in the past did. In line with our former findings using electron microscopy on cross sections, we found that 2.3 MeV protons with a deposited charge of 0.5 µC/cm2 caused no changes affecting the integrity of parchment but 2 µC/cm2 apparently did under the applied experimental conditions. To ensure the required analytical signal at a relatively low deposited charge, the detection system must be optimized for efficiency. Nevertheless, since the variability of the historic materials and the measurement set-ups are considerable, these values cannot be taken as absolutes, but only as guides, both for further IBA studies and for studies conducted in the past.

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Section: Optical Coherence Tomographysupporting

confidence: 91%

Section: Discolouration Occurring In the Parchmentmentioning

confidence: 95%

Section: Bath Testmentioning

confidence: 95%

“…The parchment had a relatively heterogeneous thickness of 150-370 µm. Pieces of approximately 2 × 2 cm 2 were cut [31].…”

Section: Parchment Samplesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%