Fig. 2: Apparatus and calibration.
From: Building a Casimir metrology platform with a commercial MEMS sensor
a Optical image of the modified ADXL203 used to collect the data presented in this paper. Also pictured is the external Au-coated plate mounted on a piezoelectric actuator (out of frame). b Schematic of full setup. The sensor X and Y outputs are fed through an 8-pole low-pass filter with a 3 Hz cutoff to isolate the desired direct current (DC) signal and then read by a 16-bit Analog to Digital Converter (ADC). The Casimir force acts along the X direction for this particular device. INSET: Diagram of Casimir cavity geometry showing sphere-plate separation (d) and sphere radius (R). For simplicity, the two support spheres are not pictured. In reality, the Ag sphere is sitting 20–30 µm above the proof-mass. c Sensor signal data as Vbias is varied at different separations. Circles are measured data and the solid lines are second order polynomial fits to the data. d. V0 and γ versus separation. These values are computed from the minima and curvature of parabolas fit to data in Fig. 2c
