Devices and methods for the characterization of areas of radiation in contaminated rooms are provided. One such device is a collimator with a collimator shield for reducing noise when measuring radiation. The determination system uses a radiation detector comprising a plurality of overlapping layers of radiation sensitive film interspersed with adjacent layers of an attenuator material. The resulting sandwich of the stacked film layers and attenuator layers provides a useful detector. The detector can be used within a radiation detector apparatus having a collimator to enable a 360 degree field of view of radiation sources within a room or enclosed environment.
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
 This invention was made with Government support under Contract No. DE-AC09-08SR22470 awarded by the United States Department of Energy. The Government has certain rights in the invention.