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Herbert Shea

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Related publications (163)

Micromachined chip-scale plasma light source

We report on the microfabrication and testing of a chip- scale plasma light source. The device consists of a stack of three anodically bonded Pyrex wafers, which hermetically enclose a gas-filled cavity containing interdigitated Aluminum electrodes. When t ...

Elsevier2009

Integrated out-of-plane nanoelectrospray thruster arrays for spacecraft propulsion

Renato Krpoun, Herbert Shea

Nanoelectrosprays, well known for their use in sample injection for the mass spectrometry of large biomolecules, can also be used in other applications such as spacecraft propulsion. The thrust generated by a single electrospray emitter is well below 1 μN, ...

Institute of Physics2009

MEMS for pico- to micro-satellites

Herbert Shea

MEMS sensors, actuators, and sub-systems can enable an important reduction in the size and mass of spacecrafts, first by replacing larger and heavier components, then by replacing entire subsystems, and finally by enabling the microfabrication of highly in ...

2009

Ad-Hoc Wireless Sensor Networks For Exploration Of Solar-System Bodies

Valentin Mitev, Mihai Adrian Ionescu, Pierre-André Farine, Herbert Shea, Cyril Botteron

In this work, we evaluate the exploration of the Solar system by ad-hoc wireless sensor networks (WSN), i.e. networks where all nodes (either moving or stationary) can both provide and relay data. The two aspects of self-organization and localization are t ...

Elsevier2009

Metal Ion Implantation for the Fabrication of Stretchable Electrodes on Elastomers

Samuel Rosset, Muhamed Niklaus, Herbert Shea

We report on low-energy metal ion implantation by filtered cathodic vacuum arc to create highly deformable electrodes on polydimethylsiloxane (PDMS) membranes. Implantation leads to the creation of nanometer-size clusters in the first 50 nm below the surfa ...

Wiley-Blackwell2009

Low-power hermetically sealed on-chip plasma light source micromachined in glass

Philippe Renaud, Herbert Shea

We report on the fabrication and testing of a chip-scale plasma light source. The device consists of a stack of three anodically bonded Pyrex wafers, which hermetically enclose a gas-filled cavity in which electrodes are used to ignite a low power (≪500 mW ...

2008

Field structure and electron life times in the MEFISTO electron cyclotron resonance ion source

Herbert Shea, Michael Bodendorfer, Peter Wurz, Kathrin Altwegg

The complex magnetic field of the permanent magnet electron cyclotron resonance (ECR) ion source MEFISTO located at the University of Berne has been numerically simulated. For the first time the magnetized volume qualified for electron cyclotron resonance ...

2008

Onset Voltage Modeling of Micromachined Colloid Thrusters

Renato Krpoun, Herbert Shea

The onset voltage of a colloid thruster is an important parameter in the design of micromachined thrusters. Because dimensions in MEMS thrusters are in the range of several tens of micrometers and because extractor electrodes can be only 5 μm from the capi ...

2008

A method to determine the onset voltage of single and arrays of electrospray emitters

Renato Krpoun, Herbert Shea

This paper reports on an accurate and rapid method to compute the onset voltage for a single or for an array of electrospray emitters with complex geometries and on the correlation of the simulation with experimental data. This method permits the exact det ...

American Institute of Physics2008

Experimental study of electrical breakdown in MEMS devices with micrometer scale gaps

Philippe Renaud, Herbert Shea

We present an experimental study of the DC breakdown voltage of MEMS interdigitated aluminum electrodes with gaps ranging from 10 to 500 μm. Unlike most research on MEMS electrodes that was done at atmospheric pressure, our work has focused on the effect o ...

2008

Voltage control of the resonance frequency of dielectric electroactive polymer (DEAP) membranes

Samuel Rosset, Muhamed Niklaus, Herbert Shea

We report on the characterization, active tuning and modeling of the first mode resonance frequency of dielectric electroactive polymer (DEAP) membranes. Unlike other resonance frequency tuning techniques, the tuning procedure presented here requires no ex ...

Institute of Electrical and Electronics Engineers2008

Low-power hermetically sealed on-chip plasma light source micromachined in glass

Philippe Renaud, Herbert Shea

2008

Microstructure of 5 keV gold-implanted polydimethylsiloxane

Samuel Rosset, Muhamed Niklaus, Herbert Shea

The first high-resolution transmission electron microscopy (TEM) cross-section images of flexible electrodes fabricated by gold ion implantation at 5 keV into polydimethylsiloxane (PDMS) are presented. A TEM sample preparation method based on cryoultramicr ...

Elsevier2008

Ion-implanted compliant and patternable electrodes for miniaturized dielectric elastomer actuators

Samuel Rosset, Muhamed Niklaus, Herbert Shea

This article presents metal ion implantation as an alternative technique to fabricate compliant electrodes for small-size dielectric elastomer actuators. When reducing the size of these actuators to below 1 cm, the ability to pattern the electrodes is adde ...

2008

Method and apparatus to determine a planet vector

Renato Krpoun, Edoardo Charbon, Noémy Scheidegger, Herbert Shea

The present invention relates to a method for a low cost Planet vector Sensor based on imaging atmospheric oxygen emission at 762 nm or at 557.7 wavelengths using either CMOS, CCD or arrays of single photon avalanche diodes (SPADs). In both daytime and nig ...

2008

Identification of the ECR zone in the SWISSCASE ECR ion source

Herbert Shea, Michael Bodendorfer, Peter Wurz, Kathrin Altwegg

The magnetic field of the permanent magnet electron cyclotron resonance (ECR) ion source SWISSCASE located at the University of Bern has been numerically simulated and experimentally investigated. For the first time the magnetized volume qualified for elec ...

2008

Modification of Conductivity and of Mechanical Properties of Electroactive Polymer (EAP) Thin Films by Titanium Ion Implantation

Samuel Rosset, Muhamed Niklaus, Herbert Shea

We present a study of the influence on Young s modulus, stress and electrical conductivity of poly-dimethylsiloxane membranes implanted with titanium ions at energies from 5 to 35 keV, with doses up to 8x10^16 ions/cm2. The motivation for this study was to ...

Materials Research Society2008

A Study of the Effects of Gamma Radiation on CMOS Single-Photon Avalanche Diodes

Cristiano Niclass, Marek Gersbach, Edoardo Charbon, Noémy Scheidegger, Herbert Shea, Lucio Carrara

The paper reports on the effects of Gamma radiation to single-photon avalanche diodes (SPADs). To the best of our knowledge, this is the first study ever conducted on SPADs fabricated in CMOS technology. A typical CMOS SPAD consists of a pn junction revers ...

2008

Mechanical characterization of a dielectric elastomer microactuator with ion-implanted electrodes

Samuel Rosset, Muhamed Niklaus, Herbert Shea

We report on the mechanical characterization and modeling of a non-prestretched dielectric elastomer diaphragm microactuator with ion-implanted electrodes under the influence of a distributed load (pressure). Thin polydimethysiloxane (PDMS) membranes (30 u ...

2008

Integrated electrospray micropropulsion system

Renato Krpoun, Herbert Shea

2007

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