A SPECT linear collimator was designed with septum thickness t, displacement between
septa d, length of septa l, and septa absorbance μ. The designer would like to find the
minimum required septa thickness t such that any beam that goes through the septa (i.e., a
beam that the collimator is intended to remove and prevent from reaching the detectors, by
hitting one of the sides of the collimator) would be attenuated to at least 0.05 of its original
intensity. As linear collimators are intended to allow only γ rays that are nearly perpendicular
to the detectors to go through, you may assume that l>>2d+t. You may consider unwanted γ
rays as rays that hit one of the sides of a septum (i.e., ignore rays which hit the front side of
the septum).