# A Survey of Electromagnetic Techniques Applied to Cultural Heritage Conservation
## 3 EM Techniques for CH Restoration
### EM Techniques for Decontamination of CH
#### 3.1.1 Application of Gamma and X-Ray for Decontamination of CH
The very high level of humidity, combined with dust--which further increases the water absorption capacity of paper--and the presence of spores everywhere in the room made the situation of the library critical. The dose applied was up to a maximum of 10 kGy, and the collection was exposed to gamma irradiation for 150 consecutive days [14]. After this, the dust was removed, and then all of the books were vacuum cleaned. Even in this case, the treatments together with monitored environment conditions turn out as a success. Gamma radiation treatments for the recovery of CH artifacts from biological damage are considered concerning paper/books in [15; 16; 17; 36], and parchments in [26]. [PERSON] et al. [18; 21] were interested in the effects of X-ray radiation on paper during irradiation, and on the short and long term. They outline how possible side effects induced by irradiation exposure are influenced by intrinsic factors, like the presence of ink and additives in the paper, as well as by the degradation state. They exposed different types of paper (laboratory model aged paper, and 18 th and 19 th century archival documents) to different radiation doses, 4-36 kGy. The results showed that aged papers have the lowest degree of  
Figure 1: The “mummy” of [PERSON] as photographed in 1912 ([PERSON] 1912, pl. XLII) compared to its reproduction on exhibit in the Museo VOEM of Sapienza (2023) [92] Credit: [PERSON] et al. Distributed under the terms and conditions of the Creative Commons Attribution (CC BY-NC-ND) license [[http://creativecommons.org/licenses/by-nc-nd/4.0/](http://creativecommons.org/licenses/by-nc-nd/4.0/)]([http://creativecommons.org/licenses/by-nc-nd/4.0/](http://creativecommons.org/licenses/by-nc-nd/4.0/)) (accessed on 2 January 2025). No changes were made to either the figure or the caption. depolymerization, and that doses below 4 kGy have no side effects, even on the long run, while doses in the range of 26-36 kGy turn into a slight UV luminescence after 21 months and yellowing after three years. [PERSON] [29] investigates evidence of eventual changes in parchment collagen due to X-ray exposition not because of decontamination treatment, but because of reading necessities through X-ray microtomography (XMT) in the case of particularly fragile parchment which cannot be unrolled. Modern (10 years old) and ancient (1769-1832) parchment samples were studied, and the conclusion is that, for fragile (but not highly gelatinized) samples, the dose of X-ray absorbed with the XMT does not cause significant changes. Investigations on gamma rays' effects on wool and silk have been conducted in [30], using radiation doses from 10 to 25 kGy. The research confirmed that a maximum dose of 10 kGy does not cause \"significant changes\" in the proteins of textiles. In [31], the effects of gamma irradiation on color changes in textiles were investigated. Samples of different textiles (wood, silk, cotton, linen) were divided into three groups: not dyed, naturally dyed, and chemically dyed. All examples were irradiated with gamma doses in the range 0.5-25 kGy. The results show that all samples darkened, but at different levels. The greatest effects have been found on linen and naturally dyed samples.