Superconducting Strips: A Concept in Thermal Neutron Detection

Abstract In the never-ending quest for better detection efficiency and spatial resolution, various thermal neutron detection schemes have been proposed over the years. Given the presence of some converting layers (typically boron, but 6LiF is also widely used nowadays), the shift towards concepts based on solid state detectors has been steadily increasing and ingenious schemes thereby proposed. However, a trade-off has been always sought for between efficiency and spatial resolution; the problem can be (at least partially) circumvented using more elaborate geometries, but this complicates the sample preparation and detector construction. Thus, viable alternatives must be found. What we proposed (and verified experimentally) is a detection scheme based on the superconducting to normal transition. More precisely, using a boron converting layer, the α particles (generated in the (n, α) reaction) crossing a low critical temperature superconducting strip some 10 μm wide have been detected; the process, bolometric in nature and based on the ionization energy loss, is intrinsically fast and the spatial resolution very appealing. In this work, some of the work done so far will be illustrated, together with the principles of the measurement and various related problems. The realization of the detector is based on industrial deposition and photolitographic techniques well within the grasp of a condensed matter laboratory, so that there is substantial room for improvement over our elementary strip geometry. Some of the plans for future work will also be presented, together with some improvements both in the choice of the materials and the geometry of the detector. View Full-Tex