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Image of the Month
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This image shows two of several offprints (1929) from the papers of Norman Feather. They might not look very exciting, but the burn marks visible are a result of spills of radioactive material, including radium (Ra226), radium D (Pb210) and polonium (Po210). The burning effect is probably due to the hydrochloric acid used to dissolve the radium salt.
The discovery of this contamination was made in December 2009 when Dr Neil Todd of Manchester University came to the Archives Centre to conduct a radiological survey and gamma analysis of the papers as part of his research into the radiological contamination of the archive material of several prominent scientists including Rutherford, Chadwick and Meitner (Todd 2010).
The laboratory notebooks and a sample of other materials from the Feather papers were initially scanned by Dr Todd for residual radioactivity with a sensitive Geiger counter. A few items found to be contaminated were further analysed by means of a NaI gamma-ray spectrometer for the purpose of radioisotope identification. Contaminated documents are all dated from Feather's early years at the Cavendish laboratory during the late 1920s. Most of the contaminated items were notebooks used to record experimental laboratory data but surprisingly the most significant contamination occurred in a collection of offprints which contributed to Feather's PhD thesis - FEAT 13/5, shown in the image.
These observations, Dr Todd argues, should be seen in the context of contamination that has been found in the papers of Ernest Rutherford and James Chadwick, who was Feather's supervisor. Radioactive contamination of the kind found in the archive material was an inevitable by-product of the era of physics between the commercial availability of radium in 1903 and the invention of particle accelerators in 1932, after which radioactive substances became largely redundant as a source of energetic particles. Feather started his career at the end of this era, when Rutherford had become less directly involved in experimental work himself. The contamination in Feather's papers is a continuation of the earlier contamination, a manifestation of the transfer of basic work from Rutherford to his students and co-workers. In conjunction with radiological data from buildings and apparatus, Todd suggests that these data provide an invaluable insight into the practises from a critical period in the history of science. A publication based on this research is forthcoming.
The discovery of mostly low-level contamination in the Chadwick and Feather papers has necessitated some changes to the way this material is handled in the Reading Room. Staff and readers have to wear disposable plastic gloves and to protect all surfaces with disposable paper. They are instructed to avoid hand to face or mouth contact and to wash hands immediately after use. The more contaminated items shown in the image have been isolated from the rest of the collection, encapsulated in polyester film and a copy made available for use.
Todd NPM (2010) Radioactive contamination in the archive papers of Norman Feather. Unpublished Report.