Embodiments include systems and methods for updating a data store in a distributed data store system. Programmable gain attenuators and programmable gain amplifiers commonly switch between signal levels using semi-conductor switches. The drain valve means includes a valve seat and a float member both located within the valve housing. The ion guideaccelerator simultaneously dampens and linearly accelerates the intact ions in the substantial absence of fragmentation of the ions to provide a substantially continuous beam of the intact ions for mass analysis. The fan is disposed proximate to the heat transfer surfaces such that the first and second directional rotations of the fan generate air flows in first and second directions with respect to the heat transfer surfaces, respectively. The light is reflected back and forth between the surfaces a plurality of times, illuminating a different portion of the field of view with each pass until, having ranged over the field of view, the light exits the reflection cavity.