A moderated neutron sensor , comprising: a single, sheet form neutron detector having a first volume; and a moderating enclosure surrounding and enclosing the single, sheet form neutron detector , wherein the moderating enclosure encloses a second volume, the second volume determined from an interior width , interior depth , and interior length of the moderating enclosure , characterized in that : a difference in a depth direction between the first volume and the second volume is larger than a difference in length between the first volume and the second volume, wherein the depth direction is measured orthogonally across an end face of the single, sheet form neutron detector , wherein a spaced distance , as measured between an exterior surface of the single, sheet form neutron detector and an interior surface of the moderating enclosure , is larger in the depth direction than a length direction, and wherein the spaced distance is at least 1.27 cm (0.5 inch), wherein a sensitivity of the single, sheet form neutron detector is a function of moderating enclosure depth measurement relative to the single, sheet form neutron detector , wherein the sensitivity of the single, sheet form neutron detector increases as the moderating enclosure depth measurement increases. a single, sheet form neutron detector having a first volume; and a moderating enclosure surrounding and enclosing the single, sheet form neutron detector , wherein the moderating enclosure encloses a second volume, the second volume determined from an interior width , interior depth , and interior length of the moderating enclosure , characterized in that : a difference in a depth direction between the first volume and the second volume is larger than a difference in length between the first volume and the second volume, wherein the depth direction is measured orthogonally across an end face of the single, sheet form neutron detector , wherein a spaced distance , as measured between an exterior surface of the single, sheet form neutron detector and an interior surface of the moderating enclosure , is larger in the depth direction than a length direction, and wherein the spaced distance is at least 1.27 cm (0.5 inch), wherein a sensitivity of the single, sheet form neutron detector is a function of moderating enclosure depth measurement relative to the single, sheet form neutron detector , wherein the sensitivity of the single, sheet form neutron detector increases as the moderating enclosure depth measurement increases. a difference in a depth direction between the first volume and the second volume is larger than a difference in length between the first volume and the second volume, wherein the depth direction is measured orthogonally across an end face of the single, sheet form neutron detector , wherein a spaced distance , as measured between an exterior surface of the single, sheet form neutron detector and an interior surface of the moderating enclosure , is larger in the depth direction than a length direction, and wherein the spaced distance is at least 1.27 cm (0.5 inch), wherein a sensitivity of the single, sheet form neutron detector is a function of moderating enclosure depth measurement relative to the single, sheet form neutron detector , wherein the sensitivity of the single, sheet form neutron detector increases as the moderating enclosure depth measurement increases. <EOS>