Radiation processing for cultural heritage preservation ......Apr 26, 2017 · Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH)[email protected]

Radiation processing for cultural heritage preservation - Romanian experience Valentin Moise Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH)[email protected]

International Conference on Applications of Radiation Science and Technology, 24 to 28 April 2017, Vienna, Austria

WOOD PAPER LEATHER TEXTILES FILM, PHOTO

ROMANIAN EXPERIENCE:

1. NEEDS FOR IONIZING

RADIATION TREATMENT

2. DOSE SETTING

BENEFITS

SIDE EFFECTS

RISK ASSEMENT


WOOD - FURNITURE - ICONS -ARCHEOLOGICAL WOOD

WOODWORMS

FUNGI


Detail of an Icon with heavy woodworms attack “Braila” Museum, Romania (2009)

Archeological wood attacked by fungi Pavement of a street in Old City, Bucharest (2015)

PAPER - BOOKS - ARCHIVES - WALLPAPER - Photography, Lithography

FUNGI

WOODWORMS / INSECTS

BACTERIA


Wallpaper from “Aman” Museum Bucharest City Museums (2016)

Documents from ”Sahia Film“ archive Bucharest, Romania (2016)

LEATHER, TEXTILES, COMPLEX COLLECTIONS - book covers - clothing, garments

FUNGI

INSECTS

WOODWORMS

BACTERIA


Leather book covers Parliament of Romania

Leather cover – (sec. XVII) Private collection, Romania

Clothing “Moldova” Museum, Iasi, Romania

FILM, PHOTOs, MAGNETIC TAPE

FUNGI

BACTERIA


Film from National Film Archive, Romania Fotography from Bucharest National Theater

Efficacy Efficiency

High energy photons penetrates any material, at any depth, for any shape

Biocidal effect can be characterized by statistical means (lethal dose, D10)

Large quantities can be treated in short time, with low costs

Gamma irradiation


Dose stetting: minimum dose – to achieve the biocidal effect maximum dose – to avoid or minimize side effects

BIOCIDAL EFFECT SIDE EFFECTS

Nu

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rviv

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Dose

Ph

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rop

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Dose

Irradiation geometry:

𝑫𝒐𝒔𝒆 𝑼𝒏𝒊𝒇𝒐𝒓𝒎𝒊𝒕𝒚 𝑹𝒂𝒕𝒊𝒐 (𝐷𝑈𝑅) =𝐷𝑚𝑎𝑥

𝐷𝑚𝑖𝑛


Gamma irradiation

Insects infestation WOOD > 5 kGy* Polychromed wood < 10 kGy TEXTILES

Romanian Experience

1: Overkill dose

Rationale: - Lethal dose for insects : < 3kGy - No side effects for wood (ligno-cellulosic structure) up

to 50 key - Most of microorganisms (fungi) will be destroyed

Polychromed wood: - Most known pigments are stable up to 10 kGy - Non destructive tests are available: color changes (CIE

L*a*b*), FT-Raman (identification of pigments), FT-IR (substrate, binder, etc)

There is no efficacy test available but there is a large experience in wood radiation treatment

* Dose measured in accessible areas of the wooden item


Fungi infestation: PAPER < 10 kGy LEATHER PHOTOS FILMS

Romanian Experience

2: Maximum dose limited by side effects

Rationale:

- Highly contaminated collections - No significant effects in physical properties of paper up to 10 kGy

Main side effect: Cellulose chain scission

Microbiological tests are available for evaluation of efficacy: - Bioburden test – total count (destructive - if allowed!) - Surface contamination – swab test, contact plate - Identification of microorganisms and determination of their

radiation resistance


Benefits and side effects Treatment Benefits Side effects

Insect

disinfestation

• The active attack is stopped and there is no recurrence of insect infestation over the years (for more than 1000 items treated)

• No side effects for wood • No side effects for common old

pigments • Undiscernable changes of

proteins from wool (unpublished data)

Fungi disinfection • The active attack is stopped and microbial contamination is reduced to a safe level

• Decrease of average degree of polymerisation of cellulose from paper and other cellulosic fibers Undiscernable changes of collagen structure from leather (unpublished data)


Efficacy of insect disinfestation: - No recurrence of insect infestation after the years

Examples:

Iconostasis from two churches highly attacked by woodworms (2002, 2005 – revisited in 2015)

“Aman” Museum wooden inventory (furniture, flooring, wainscoting, exhibits) with extensive woodworms attack. (2010 - revisited in 2015)

Carpets from “Mogoșoaia Palace” Musem (2015)


1. bioburden testing before and after the treatment (Moise et al, 2012) (destructive, time consuming, costly, disregards “non-cultivable” microorganisms)

2. Testing the surface contamination before and after the treatment (recovers only a part of the total bioburden, disregards “non-cultivable” microorganisms)

3. Identification of main contaminants and estimation of treatment efficacy based on their radiation resistance (needs fungi database – in progress)


Efficacy of fungi disinfection:

Treatment Dose (kGy) No of Log reduction

„Royal patents” Collection (Romanian State Office for Inventions and Trademarks, 2016) ~ 4 tons of documents

5.0 3

Treatment Dose (kGy) No of Log reduction

„Oficial Journal Collection” (Romanian Parliament Archives, 2014) ~ 4 tons of documents

Average: 6.6 > 3

„Museum inventory” (Bucharest National Theater, 2015) ~ 6 tons of documents, stage props, photos, etc

Minimum: 6.7

Maximum: 9.0

3

„Sahia Film Archive” (Romanian Ministry of Culture, 2016) ~ 3 tons of documents

Average: 6.8 5

Surface contamination:

Bioburden:

Side effects: Cellulose radiolytic degradation

scission g, e-

Charlesby, 1955: “random scission”

Bouchard et al, 2006: “the molecule cannot be cleaved precisely at the bombardment site”


Experiments on paper: • Significant decrease of cellulose DP at low doses: 50-60% down for paper

irradiated at 10 kGy (Calvini and Santucci 1978, Adamo et al, 1998, Area et al, 2014) • No significant changes for macroscopic properties of paper: mechanical strength,

color, pH (Calvini and Santucci 1978, Adamo et al, 1998, Moise et al 2012) • Paper with very low DP (comparable with DP of cellulose in paper naturally aged,

3-400 years old) is less sensitive to irradiation than new paper (Bicchieri et al, 2016)

Reduction of size of cellulose molecules (decrease of DP – degree of polymerization) is associated with “ageing” of cellulose

Natural ageing degradation of cellulose is attributed to acidic hydrolysis process

In natural fibers, cellulose is packed (by hydrogen bonds) in a specific manner: micro-fibrils (supramolecular structures) and fibrils.


The significant decrease of cellulose DP due to radiation treatment is not reflected in macroscopic properties of paper.

Possible explanation: acidic hydrolysis advances from the exterior of the cellulose structural units (fibrils, micro-fibrilis) and progressively destroy the hydrogen bonds structure, while ionizing radiation acts in entire volume of structural units and preserves the hydrogen bonds structure [Moise et al, 2014]

Side effects: Cellulose radiolytic degradation

Risk assessment - Help for decision for an intervention


1. Initial risk assessment for paper documents under heavy biological attack:

No Hazard

P S IP Initial risk

Actions*)

Probability 1-unlikely 2-seldom 3-likely

Severity 1-negligible 2-moderate 3-critical

Priority

index PxS

1 - 3 low

4 - 6 medium 7 - 9 high

1 Total loss of physical integrity of documents and/or total loss of written information

2 3 6 HIGH

Radiation treatment 2 Documents are nor accessible due to health

hazard 3 3 9

No Hazard P S IP Residual risk 1 Total loss of physical integrity of documents

and/or total loss of written information 1 3 3

LOW 2 Documents are nor accessible due to health hazard 2 1 2

3 Side effects of the radiation treatment 2 2 4

2. Residual risk assessment after treatment:

Thank you for your attention!

Radiation processing for cultural heritage preservation - Romanian experience

Valentin Moise, Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH)

[email protected]