A new method for searching for free fractional charge particles in bulk matter

Loomba, D.; Halyo, V.; Lee, Eric R.; Lee, Irwin T.; Kim, Peter C.; Перл, М.

doi:10.1063/1.1308268

“…We have demonstrated that the piezoelectric liquid drop generation technique, originally used for searching for free fractional charge particles in liquids [30,32], The interval corresponds to thousands of high voltage pulses (consistent with the "inverse logarithmically slow" density relaxation in a vibrated granular material discussed for instance in [39,40]) and the clot generation process resembles water dripping from a slightly open tap. The most puzzling question that remains is the origin of forces which bind the powder particles in the clot.…”

Section: Discussionmentioning

confidence: 99%

“…The design of the piezoelectric droplet generator used in our experiment has been described in detail elsewhere [31,32]. The dropper consists of a pipette- …”

Section: Experimental Approachmentioning

confidence: 99%

“…Variations of the method were successfully used in searches for free fractional charge particles in pure liquids or liquid suspensions of powdered bulk materials [26,27,28,29,30,31,32,33]. However, implementation of this method "as-it-is" is restricted to elements and substances whose melting temperature does not significantly exceed the operational temperature of the dropper's piezoelectric transducer [34].…”

Section: Introductionmentioning

confidence: 99%

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Production of Dry Powder Clots Using Piezoelectric Drop Generator

Lee¹

2002

0

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We have demonstrated that piezoelectrically driven, squeeze mode, tubular reservoir liquid drop generation, originally developed as a "drop-on-demand" method for ejection of microdrops of pure liquid or liquid suspensions of powdered bulk materials, can successfully operate with dry powder. Spherical silver powder with maximum particle diameter of 20 µm (-635 mesh) was loaded into and ejected from a 100 µm orifice glass dropper with flat piezoelectric disk driver.Time of flight experiments were performed to optimize the dropper operation parameters and to determine the size and velocity of the ejected particles. It was found that at certain values of the amplitude, duration, and repetition rate of the voltage pulses applied to the dropper piezoelectric disk, one can produce ejection of powder clots of a stable size, comparable with the dropper orifice diameter.In contrast to the dropper operation with a liquid, in the case of silver powder, a clot is not ejected at each high voltage pulse, but quasi-periodically with an interval corresponding to thousands of pulses. The application of the dry powder clot generation technique for injection of atoms into helium buffer gas at cryogenic temperatures is discussed.

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“…The design of the piezoelectric droplet generator used in our experiment has been described in detail elsewhere [31,32] We found that the dropper operation with dry powder significantly differs from the original drop-on-demand regime where a liquid drop is generated at each high voltage pulse. In our experiment, a clot is generated quasi-periodically with many pulses necessary to produce one clot, and with a strong ejection dependence on the pulse repetition frequency.…”

Section: Experimental Approachmentioning

confidence: 99%

Production of dry powder clots using a piezoelectric drop generator

Yashchuk

¹

,

Sushkov

²

,

Budker

³

et al. 2002

Review of Scientific Instruments

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We have demonstrated that piezoelectrically driven, squeeze mode, tubular reservoir liquid drop generation, originally developed as a "drop-on-demand" method for ejection of microdrops of pure liquid or liquid suspensions of powdered bulk materials, can successfully operate with dry powder. Spherical silver powder with maximum particle diameter of 20 µm (-635 mesh) was loaded into and ejected from a 100 µm orifice glass dropper with flat piezoelectric disk driver.Time of flight experiments were performed to optimize the dropper operation parameters and to determine the size and velocity of the ejected particles. It was found that at certain values of the amplitude, duration, and repetition rate of the voltage pulses applied to the dropper piezoelectric disk, one can produce ejection of powder clots of a stable size, comparable with the dropper orifice diameter.In contrast to the dropper operation with a liquid, in the case of silver powder, a clot is not ejected at each high voltage pulse, but quasi-periodically with an interval corresponding to thousands of pulses. The application of the dry powder clot generation technique for injection of atoms into helium buffer gas at cryogenic temperatures is discussed.

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“…Given a known radius from the vertical terminal velocity measurement, the charge of the drop can be calculated from the lateral terminal velocity and the value of the electric field [6,7,8]: …”

Section: Horizontal Electric Fieldmentioning

confidence: 99%

Automated electric charge measurements of fluid microdrops using the Millikan method

Lee¹,

Halyo²,

Lee³

et al. 2004

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Automated measurements of the electric charge of fluid microdrops precise to up to 0.016 of an electron charge have been made using machine-vision systems to observe the motion of fluid microdrops in air under the influence of an oscillating electric field. The fluid drop diameters have ranged from 7 to 25 µm with smaller diameter drops being measured to higher precision. The experimental runs performed for the purpose of attempting to find isolated fractionally electrically charged particles have measured the charges of tens of millions of fluid microdrops using piezoelectrically driven drop-on-demand inkjet-like droplet ejectors as fluid drop sources.

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A new method for searching for free fractional charge particles in bulk matter

Abstract: A new method to calculate the beam charge for an integrating current transformer Rev. Sci. Instrum. 83, 093302 (2012);

Cited by 6 publications

References 11 publications

Production of Dry Powder Clots Using Piezoelectric Drop Generator

Production of Dry Powder Clots Using Piezoelectric Drop Generator

Production of dry powder clots using a piezoelectric drop generator

Automated electric charge measurements of fluid microdrops using the Millikan method

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