LANSCE harp upgrade: analysis, design, fabrication and installation

The primary goal of this newly installed beam profile measurement is to provide the facility operators and physicists with a reliable horizontal and vertical projected beam distribution and location with respect to the proton beam target and beam aperture. During a 3000-hour annual run cycle, 5 {mu}C of charge is delivered every 50 milliseconds through this harp to the downstream TRMS Mark III target. The resulting radioactive annual dose near this harp is at least 6 MGy. Because of this harsh environment, the new harp design has been further optimized for robustness. For example, compared to an earlier design, this harp has half of the sensing wires and utilizes only a single bias plane. The sensing fibers are 0.079-mm diameter SiC fibers. To hold these fibers to a rigid ceramic structure, a collet fiber-clamping device accomplishes the three goals of maintaining a mechanical fiber clamp, holding the sense fibers under a slight tensile force, and providing a sense-fiber electrical connection. This paper describes the harp analysis and design, and provides fabrication, assembly, and some installation information, and discusses wiring alterations.