Structural Analysis of Narratives with the Coq Proof Assistant

Abstract. This paper proposes a novel application of Interactive Proof Assistants for studying the formal properties of Narratives, building on recent work demonstrating the suitability of Intuitionistic Linear Logic as a conceptual model. More specifically, we describe a method for modelling narrative resources and actions, together with constraints on the story endings in the form of an ILL sequent. We describe how well-formed narratives can be interpreted from cut-free proof trees of the sequent obtained using Coq. We finally describe how to reason about narratives at the structural level using Coq: by allowing to prove 2nd order properties on the set of all the proofs generated by a sequent, Coq assists the verification of structural narrative properties traversing all possible variants of a given plot

Radon in the DRIFT-II directional dark matter TPC: emanation, detection and mitigation

Radon gas emanating from materials is of interest in environmental science and also a major concern in rare event non-accelerator particle physics experiments such as dark matter and double beta decay searches, where it is a major source of background. Notable for dark matter experiments is the production of radon progeny recoils (RPRs), the low energy (~ 100 keV) recoils of radon daughter isotopes, which can mimic the signal expected from WIMP interactions. Presented here are results of measurements of radon emanation from detector materials in the 1 m3 DRIFT-II directional dark matter gas time projection chamber experiment. Construction and operation of a radon emanation facility for this work is described, along with an analysis to continuously monitor DRIFT data for the presence of internal 222Rn and 218Po. Applying this analysis to historical DRIFT data, we show how systematic substitution of detector materials for alternatives, selected by this device for low radon emanation, has resulted in a factor of ~ 10 reduction in internal radon rates. Levels are found to be consistent with the sum from separate radon emanation measurements of the internal materials and also with direct measurement using an attached alpha spectrometer. The current DRIFT detector, DRIFT-IId, is found to have sensitivity to 222Rn of 2.5 μBql−1 with current analysis efficiency, potentially opening up DRIFT technology as a new tool for sensitive radon assay of materials

100 years of radionuclide metrology

The discipline of radionuclide metrology at national standards institutes started in 1913 with the certification by Curie, Rutherford and Meyer of the first primary standards of radium. In the early years, radium was a valuable commodity and the aim of the standards was largely to facilitate trade. The focus later changed to providing standards for the new wide range of radionuclides, so that radioactivity could be used for healthcare and industrial applications while minimising the risk to patients, workers and the environment. National measurement institutes responded to the changing demands by developing new techniques for realising primary standards of radioactivity. Looking ahead, there are likely to be demands for standards for new radionuclides used in nuclear medicine, an expansion of the scope of the field into quantitative imaging to facilitate accurate patient dosimetry for nuclear medicine, and an increasing need for accurate standards for radioactive waste management and nuclear forensics.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard