Abstract: Systems, devices, and methods for collimating a neutron beam to specified deliverable formats having targeted beam diameters and direction are described. Examples of a neutron collimator assembly can include numerous components based on location, function, dimension, and/or constituent material. The components can include, neutron beam collimators, a beam stop, a mounting assembly, electro-mechanical actuators, an electronic controller, a safety interlock system, a moveable radiation shield, a safety cover, and an adjustable patient platform. In addition, examples of variable aperture neutron beam collimators such as nested neutron beam collimators and collimators with a diaphragm iris are described. Materials are also described.

Abstract: An apparatus and method for accurately weighing a rail car coupled to other rail cars without uncoupling the rail car to be weighed includes a hydraulically operated positioning device assembly with opposed pushers that can be elevated to hold the axle of a rail car uptrack of the car to be weighed, a scale mounted downtrack of the rail car positioning device, and a car stop mounted downtrack of the scale that can be elevated to block the wheels of a car downtrack of the car being weighed.The rail car positioning device engages the car uptrack of the car to be weighed, moves the car to be weighed over the scale, and, by reversibly moving the car, centers the car over the scale. The car stop then engages the downtrack car to maintain it and other cars coupled to it downtrack in a fixed position during weighing and filling of the car on the scale. The carriage assembly then releases the car on the scale and moves uptrack where it acquires a hold on the next empty car.