The Jalousie neutron detector concept
10-Boron based neutron detector, our alternative for 3-He filled PSD counter tubes, under prototyping!
The Jalousie neutron detector is a new detector in its prototyping phase, developed to serve as alternative for classical 3-He position sensitive detector tubes (PSD). It is thus thought to resolve today´s 3-He availability crisis for neutron scattering instruments. The neutron converting material is 10-Boron and replaces 3-He. The comparatively small overall detection efficiency of an individual layer is enhanced by tilting the layer towards the incoming neutron path, thus increasing the effective absorption depth. Additionally, eight such boron layers are arranged along any neutron path to further enhance the overall detection efficiency. A Jalousie detector system comprises many lamella shaped individual modules, where each makes up an enclosed multi wire proportional chamber with two anode planes and four cathode planes that carry the converter layers. Several such lamellae, when stacked and tilted with respect to the neutron paths, may be arranged to cover square meter sized planes, or alternatively a cylindrical surface to enclose a scattering sample. The design depicted is under development and currrently in a prototyping stage for POWTEX at FRM II, where an overall area of 9 sqm will be covered. Spatial resolution is 5 mm (FWHM) and may be altered through design parameters. The POWTEX lamella length was chosen to be 1,8m and includes a concentric orientation of the readout channels towards the scattering centre.