The suitability of large area drift chambers as the technology choice for the cosmic ray inspection and passive tomography (CRIPT) project

The CRIPT project brings together several Canadian institutions, concerned with the detection of Special Nuclear Materials (SNM), addressing a requirement at ports-of-entry for detection of SNM in the many thousands of containers that flow into and out of Canada every day, while at the same time providing a way of monitoring the contents of nuclear waste storage containers, for waste management and non-proliferation reasons. The scale of these applications is large - typically tens of cubic metres, requiring detectors that can cover a large area at a minimum cost. The CRIPT project considered drift chambers adapted from high energy physics experience, as one of its technology choices. We report here on the performance of a full scale prototype, which covers an area of 2.4m × 1.2m with only 6 readout channels, and provides a 2D data point with accuracies (in x and z) of around 2 mm.