Rotor electrometer: a new instrument for fractional charge searches

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5236155

Price, J C

A very sensitive electrometer with a charge resolution of less than the charge of one electron is described. The instrument has been developed in hopes that it will allow fractional charge search experiments with very large samples. The method employed is electronic, in contrast to other fractional charge search techniques which involve the measurement of a small force. Pairs of conducting pads are placed around the perimeter of a high speed magnetically levitated rotor, with one member of each pair grounded, and the other capacitively coupled to a low noise JFET amplifier. As the pads move past the stationary sample, which hangs from a quartz glass fiber, a periodic voltage proportional to the charge appears at the amplifier input. Amplifier noise limited resolution of better than one electron per roots hertz may be achieved in principle, and in practice a resolution of about one third of an elementary charge has been demonstrated. Photoemission of electrons from the sample is used to calibrate the instrument directly in terms of the electron's charge.

• Research Organization: Stanford Univ., CA (USA)
• OSTI ID: 5236155
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420800 -- Engineering-- Electronic Circuits & Devices-- (-1989)
440300* -- Miscellaneous Instruments-- (-1989)
47 OTHER INSTRUMENTATION
AMPLIFIERS
DESIGN
ELECTRIC CHARGES
ELECTRIC MEASURING INSTRUMENTS
ELECTRICAL EQUIPMENT
ELECTROMETERS
ELECTRONIC EQUIPMENT
EQUIPMENT
MEASURING INSTRUMENTS
MEASURING METHODS
NOISE
RESOLUTION