ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
We have developed a novel multitip scanning Kelvin probe which can measure changes in biological surface potential ΔVs to within 2 mV and, quasisimultaneously monitor displacement to 〈1 μm. The control and measurement subcomponents are PC based and incorporate a flexible user interface permitting software control of each individual tip, measurement, and scan parameters. We review the mode of operation and design features of the scanning bio-Kelvin probe including tip steering, signal processing, tip calibration, and novel tip tracking/dithering routines. This system uniquely offers both tip-to-sample spacing control (which is essential to avoid spurious changes in ΔVs due to variations in mean spacing) and a dithering routine to maintain tip orientation to the biological specimen, irrespective of the latter's movement. These features permit long term (〉48 h) "active" tracking of the displacement and biopotentials developed along and around a plant shoot in response to an environmental stimulus, e.g., differential illumination (phototropism) or changes in orientation (gravitropism). © 1999 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1149678
Permalink