Processing this raw data requires relating changes in to , which can be accomplished by considering the experiment geometry and the changes that occur as the mechanism and apparatus transition from room temperature to cryogenic temperatures and as the spacer that constrains the magnet–superconductor separation during cooling is removed. At room temperature, the location of the reflected beam spot is determined by the deviation of the mirror normal from 45 deg, , the laser misalignment, , and the initial tilt of the lever arm, [Fig. 4(b)]. Since the pivot mirror rotates with the lever arm, the total tilt changes the height of the spot where the laser intersects the mirror, shifting the height of the reflected beam by . As liquid nitrogen is added, the apparatus expands/contracts on a global scale, changing the position of the reflected beam spot by . Similarly, contraction of the magnet, superconductor, and spacer alters the total height of the mechanism, causing the pivot arm to rotate by an additional amount . These two effects are distinguished by comparing changes in the location of the reflected pivot beam spot to changes in the location of a reflected spot from a laser aimed at a reference mirror attached to a stationary part of the apparatus. After the experiment reaches thermal equilibrium, the spacer between the magnet and the superconductor is removed, and the mechanism is loaded with a known weight. As the magnet-superconductor separation decreases in response to the weight, the lever arm rotates by an additional amount .