Cosmic ray muon radiography utilizes highly penetrating cosmic ray muons to image the density profile of an object of interest. Here we report on a trial to use a portable field-deployable cosmic ray muon tracking system in order to image the whole overburden of a UK railway tunnel with short-duration scans (c. 30 min). An unknown overburden void was identified and, after trial, confirmed by railway authorities. These experiments demonstrate the identification of hidden construction shafts with high levels of statistical significance as density anomalies within the data.

Abstract-Fused Deposition Modelling has been used to produce a small, single wire, Iarocci-style drift tube to demonstrate the feasibility of using the Additive Manufacturing technique to produce cheap detectors, quickly. Recent technological developments have extended the scope of Additive Manufacturing, or 3D printing, to the possibility of fabricating Gaseous Radiation Detectors, such as Single Wire Proportional Counters and Time Projection Chambers. 3D printing could allow for the production of customisable, modular detectors; that can be easily created and replaced and the possibility of printing detectors on-site in remote locations and even for outreach within schools.The 3D printed drift tube was printed using Polylactic acid to produce a gas volume in the shape of an inverted triangular prism; base length of 28 mm, height 24.25 mm and tube length 145 mm. A stainless steel anode wire was placed in the centre of the tube, mid-print. P5 gas (95% Argon, 5% Methane) was used as the drift gas and a circuit was built to capacitively decouple signals from the high voltage. The signal rate and average pulse height of cosmic ray muons were measured over a range of bias voltages to characterise and prove correct operation of the printed detector.

Cosmic Ray Neutron Sensing (CRNS) is a powerful technique that allows non-invasive monitoring of soil moisture on length scales well matched for agricultural applications. One factor limiting the use of the technique within industrial agriculture settings is the high initial cost of Helium-3 or BF3 tubes typically used for ground level neutron monitoring. This paper discusses the use of Geant4 to design and optimise an alternative scintillator based epi-thermal neutron detector that may be applicable for challenges where cost is a higher driving factor than temporal resolution.

Figure 1: Summary of the Cosmic Ray Neutron Sensing (CRNS) technique. Since cosmogenic neutrons are more likely to be absorbed in the soil when hydrogen content is high, the number of neutrons detected by a passive neutron monitor placed above ground is inversely correlated with the local hydrogen content in a 200 m radial area, and down to approximately 30 cm soil depth.