In an atom interferometer, improved results are obtained by configuring the interferometer to have a baseline fringe pattern, in combination with spatially resolved measurements at the interferometer ports. The over-voltage protection circuit structure receives an alternating current input and comprises a relay circuit, a voltage detection module, and an energy supply circuit. Comparing the locations of the centroids over multiple images may be used to resolve a number of objects imaged by the array. The interface software implements techniques for managing multiple users using the same user interface component by allocating physical spaces within the multi-touch display component and coordinating movement of displayed objects between the physical spaces. The system forms a two-dimensional beam that is symmetric about the primary beam axis at the detector position, regardless how the beam is collimated by the collimating blocks.