Fort Nelson Staff and Volunteers Experience Crime Scene Technology Training
Royal Armouries staff and volunteers were recently awarded a Training Bursary to learn how to use a portable X-ray fluorescence analyse(XRF), to enable the collection of forensic evidence from the collection of Artillery held at Fort Nelson. Conservator Matthew Hancock tells the story.
Fort Nelson staff and volunteers were recently awarded a Training Bursary from South East Museum Development Programme to learn how to use a portable X-ray fluorescence analyser (XRF), to enable the collection of forensic evidence from the collection of Artillery held at Fort Nelson.
XRF is used in many industries for elemental and chemical analysis of material in order to find out the structure of the material under forensic investigation. The use of XRF in industry is wide spread form non-destructive analysis of archaeological objects, the mining industry to the local scrap metal dealer and the police forensic laboratory, with some XRF units been manufactured for specific industries, for example as previously mentioned mining to determine the quality of the minerals to be mined. The main industrial user of XRF is the waste recycling industry.
What is X-ray florescence and why use it in Museum Conservation?
Atoms contained in materials can be excited when bombarded by X-rays or gamma rays, XRF is the emission of characteristic “secondary” or fluorescent X-rays from the bombarded material, as these characteristic rays produce a unique pattern like a finger print or DNA from each material. Then readings of these secondary rays can be interpreted to provide the chemical make-up of the material enabling the identification of the material or the study of the chemicals in the material, this study might be able to be used to confirm the date of the object or where the material originated from, important questions when heritage professionals are trying to establish provenance of an object.
Museums use XRF in many different conservation disciplines, these include metal identification, chemical analysis of pigments for dating and identification of easel paintings and non-destructive material identification in archaeology.
The particular areas of interest to Fort Nelson are metal identification, chemical analysis and identification of pigments and materials.
Reasons the Royal Armouries invested in XRF
The Royal Armouries, invested in this technology to enable us to achieve one of our core Corporate Plan 2014-2019 aims. Research and dissemination by improving our understanding of objects by forensic examination and sharing this information with other heritage organisations in Hampshire, United Kingdom and internationally.
This investment also helps with achieving three other of our core Corporate Plan 2014-2019 aims these are, Conserve and Manage the Collection, Enhance the Collection and Display and Interpret the collection.
The Royal Armouries purchased a hand held portable XRF unit that can be moved easily between all three of the Armouries sites, to aid us to reach the aims and objectives in the Corporate Plan.
The importance of involving Volunteers and Staff in this project
A challenge recognised by Fort Nelson with this volunteer programme and with non-academic technical staff is how to involve the team members in conservation science into in a way that will be interesting and engaging for the participants that doesn’t involve a long training and expensive course in chemistry.
Fort Nelson has a training programme for conservation volunteers, along with staff training programmes. These programmes are primarily designed to meet the training needs of staff and volunteers, they are also intended to include development of staff and volunteers, however, with pressure on budgets development part of the programs can often be put on hold or postponed or only the staff that are essential to a project are trained to use the equipment in the case of XRF this would normally be the Conservator as analytical conservation science would be part of the job description and person specification. Fort Nelson and the Royal Armouries are not the only organisation to suffer from this situation and this is why the Conservator developed the volunteer training programme to also include development of the volunteers, as it was believed that without development volunteers and the museum will fail to get the full benefits of volunteers and the experience of volunteers would be substantially reduced. The same is also true for collections staffs that don’t have the job title of Conservator as these staff and volunteers work closely with objects. The importance of developing skills in conservation science cannot be underestimated otherwise the work will develop into substandard conservation. This substandard conservation work will put our heritage at risk, because the potential loss of historic evidence.
The decision to include volunteers and other collections staff in the training was not only because of the training programmes in the preceding paragraphs. In addition to commitment to staff development at Fort Nelson the proposed XRF artillery database project would be a large undertaking that would be require more personnel than just the Conservator to compete in a reasonable timeframe.
Making the most of the Equipment
During the training it became apparent that setting up the equipment correctly was critical to achieve accurate results. The importance of creating meticulous information for use in peer reviewed research papers is fundamental to any heritage forensic project.
The method of ensuring the results are accurate is by calibrating the XRF unit, this will require the use of the system software in some units and manual calibrating by the used of standards these are certificated disks of material with the chemical composition of the material listed on the certificate. For example a brass standard might contain the chemical composition in table 1 below.
Table 1 the chemical composition of brass standard
Courtesy of http://www.basrid.co.uk
An example of the importance of calibration was demonstrated during the training when one of the delegates brought in a sample of metal that was gold plated, the instructor used the settings to on the unit to show if the calibration is incorrect the XRF unit could give a reading for pure gold instead of gold plate.
Another area that is essential for the success of a project is the interpretation of the results, understanding the information from the XRF is imperative because if the results are incorrectly read this could be the difference between a fake and a genuine work of art. In the case of easel paintings this could be used to provide evidence for an entry in the catalogue raisonné. This evidence could be the difference between a painting surviving and in some case been destroyed by the estate of the artist. As in the case of the Marc Chagall painting featured on the BBC programme Fake or Fortune . The programme has often used forensic methods including XRF and other types of X-ray methods to provide information on the chemical make-up of pigments and also to date the pigments.
The training provided a useful section on the capabilities of the equipment. This module explained what the equipment was capable of and also the limitations of the equipment. Although this might not appear positive it was important to cover the subject, because if the capabilities of the equipment are misunderstood the research could fail. The limitation of the equipment that was of most interest to Fort Nelson was that XRF is unable to produce information on carbon content of materials. Carbon content is of interest when researching iron used in gun manufacture. However the origins of iron used in the manufacture of some the guns in the collection is historically documented, so fortunately this limitation was not crucial to any of our XRF projects.
No modern course would be complete without covering the subject of safety. However, while learning about safety for the XRF unit it gave us the chance to use a Geiger counter to measures the x-rays from the unit while taking a reading from a sample of material. Using a Geiger counter was interesting experience and lightened up the safety aspect of the course. Although you are able to purchase a Geiger counter for a few hundred pounds, the cheap ones can’t be re-calibrated and you would need a new one every year. Fort Nelson will be using the sensible method of monitoring radiation using the more economical process of dosimeters at a cost of under a hundred pounds a year.
Planning your XRF Project: What you need to consider
Planning the project might be common sense but with X-ray there are some extra things to consider like radiation protection along with the normal what, why and budget that can be overlooked below is an outline of four of the most important considerations when planning a XRF project.
Types of XRF
The first consideration when planning your project is the type of XRF equipment you might require as not only are their units for the type of work as previously mentioned but there are portable units, desk top units and floor standing units. The key to choosing the right type of equipment for your project is research and budget. The cost of XRF units is not cheap but you can hire units or send samples to a third party to be analysed.
The next consideration is a training and safety issue, although the training in the use of the equipment has been completed there is still training to complete, as you will need a Radiation Protection Supervisor (RPS) on site. RPS needs to “know enough about radiation protection principles and procedures, the requirements of the Regulations and the arrangements in local rules to enable them to supervise the work safely “Regulation 17 states. Another part of the regulations is the Radiation Protection Advisor this is covered in Regulation 13 and will have to be an outside Consultant As Regulation 13 states “that every employer shall consult with a Radiation Protection Advisor.”
Planning the project What?/ Why ? / Budget / Staff
The training is complete you have your RPS on site and your Consultant RPA you advised Health and safety that you are going to start X-ray work on site and you’re ready to go, but this is the crucial bit and needs to be done before you invest the money into equipment, is the two questions of what and why? Then you have the budget it cost time and money to have staff or volunteers tied up on forensic projects. The questions have to be asked: what are we going to do and why is it worth the time and investment? Are our projects going to present value for money for our organisation? Value for money might not necessary mean a financial return; it could be raising the museum’s profile in research. With the costs involved in XRF it is imperative that any value for money criteria is achieved because questions will be asked if the targets are not met, with the current restrictions on spending in most institutions.
Dissemination of Results
The projects complete the reports are written, the job done… well not entirely. It’s not much help if the results are kept in the museum archive or Library and the information collected is not used in any meaningful way. The information might help with decision making on types of treatment, reducing risks when conserving objects. The really useful part of dissemination is to share your results in a paper or publication, the reason being that sharing results can help to achieve value for money criteria; it’s also a good professional practice to share research and have it peer reviewed.
Fort Nelson's future XRF project
Fort Nelson is planning to create the previously mentioned XRF database of the polymer coatings currently used on the objects in the collection and the chemical make-up of the metals used in the construction of the collections. This database will be used for a major research project in the effectiveness of polymer coatings on historic artillery and the effect when combined with moisture on corrosion products. The database will also be used to study the chemical structure of the different metals used in the collection. The data base will also be a useful resource when treating objects as we will have knowledge of the materials on the guns and this can affect the treatment. It also helps when assessing the risks knowing what you’re dealing with an example could be the amount of lead in the paint work.
 Shugar A N, Mass J L (2012) Studies in Archaeological Sciences Louvain University Press Belgium