In a braking control apparatus, a plurality of pumps are driven by a common first motor. The rate at which material particles are sputtered from the target and thus deposited on the wafer is controllable in response to power supplied to the target. The normalized sensitivity values can be scaled based on a tolerance factor, and the adjusted sensitivities used to model the behavior of each component of the bitcell in subsequent simulations. Methods for making and using the hypodermic needle assemblies are also disclosed.