Publications de Sylvain Dunand

Hydrogenated Amorphous Silicon Charge-Selective Contact Devices on a Polyimide Flexible Substrate for Dosimetry and Beam Flux Measurements

Sylvain Dunand, Nicolas Würsch, Jonathan Emanuel Thomet

Hydrogenated amorphous silicon (a-Si:H) devices on flexible substrates are currently being studied for application in dosimetry and beam flux measurements. The necessity of in vivo dosimetry requires thin devices with maximal transparency and flexibility. ...

MDPI2025

Cleopatra: a 12-channel recycling integrator ASIC for the readout of hydrogenated amorphous silicon detectors in radiotherapy dosimetry

Sylvain Dunand, Nicolas Würsch, Jonathan Emanuel Thomet

The Cleopatra ASIC is a 12-channel prototype ASIC for the readout of hydrogenated amorphous silicon sensors used for real-time dosimetry in radiation diagnostic and radiation therapy. The architecture is based on a current to frequency conversion based on ...

2025

HASPIDE: a project for the development of hydrogenated amorphous silicon radiation sensors on a flexible substrate

Giovanni De Cesare, Mikaël Martino, Sylvain Dunand, Jonathan Emanuel Thomet, Luca Massimiliano Antognini, Matthew James Large

Hydrogenated amorphous silicon (a-Si:H) is a material with a very good radiation hardness and with the possibility of deposition on flexible substrates like Polyimide (PI). Exploiting these properties, the HASPIDE (Hydrogenated Amorphous Silicon PIxels DEt ...

Iop Publishing Ltd2024

A Front-End Circuit in 28 nm CMOS for Hydrogenated Amorphous Silicon Detectors in Clinical Dosimetry

Sylvain Dunand, Nicolas Würsch, Jonathan Emanuel Thomet, Luca Massimiliano Antognini

This paper presents the design and the characterization of a front-end circuit, designed in 28 nm CMOS, for real-time dosimetry in radiation diagnostics and radiation therapy. The front-end circuit is optimized for sensors made of hydrogenated amorphous si ...

Institute of Electrical and Electronics Engineers Inc.2024

Dosimetry of microbeam radiotherapy by flexible hydrogenated amorphous silicon detectors

Sylvain Dunand, Nicolas Würsch, Jonathan Emanuel Thomet

Objective. Detectors that can provide accurate dosimetry for microbeam radiation therapy (MRT) must possess intrinsic radiation hardness, a high dynamic range, and a micron-scale spatial resolution. In this work we characterize hydrogenated amorphous silic ...

IOP Publishing Ltd2024

Mobility Gaps of Hydrogenated Amorphous Silicon Related to Hydrogen Concentration and Its Influence on Electrical Performance

Sylvain Dunand, Nicolas Würsch, Jonathan Emanuel Thomet

This paper presents a comprehensive study of hydrogenated amorphous silicon (a-Si)-based detectors, utilizing electrical characterization, Raman spectroscopy, photoemission, and inverse photoemission techniques. The unique properties of a-Si have sparked i ...

2024

Amorphous silicon detectors for proton beam monitoring in FLASH radiotherapy

Christophe Ballif, Sylvain Dunand, Nicolas Würsch, Jonathan Emanuel Thomet, Luca Massimiliano Antognini

Ultra-high dose rate radiation therapy (FLASH) based on proton irradiation is of major interest for cancer treatments but creates new challenges for dose monitoring. Amorphous hydrogenated silicon is known to be one of the most radiation-hard semiconductor ...

Elsevier BV2024

Characterization of Hydrogenated Amorphous Silicon Sensors on Polyimide Flexible Substrate

Sylvain Dunand, Nicolas Würsch, Jonathan Emanuel Thomet

Hydrogenated amorphous silicon (a-Si:H) is a material having an intrinsically high radiation hardness that can be deposited on flexible substrates such as polyimide (PI). For these properties, a-Si:H can be used for the production of flexible sensors. a-Si ...

2024

Characterization of a flexible a-Si:H detector for in vivo dosimetry in therapeutic x-ray beams

Sylvain Dunand, Nicolas Würsch, Jonathan Emanuel Thomet, Luca Massimiliano Antognini, Matthew James Large

BackgroundThe increasing use of complex and high dose-rate treatments in radiation therapy necessitates advanced detectors to provide accurate dosimetry. Rather than relying on pre-treatment quality assurance (QA) measurements alone, many countries are now ...

Wiley2024

TCAD modelling of a-Si:H devices for particle detection applications

Sylvain Dunand, Nicolas Würsch, Luca Massimiliano Antognini, Giulia Rossi, Matthew James Large

Hydrogenated amorphous silicon (a-Si:H) has been proposed as a suitable material for particle detection applications thanks to its property to be deposited over a large area and above a variety of different substrates, including flexible materials. Moreove ...

Elsevier Sci Ltd2023

X-ray qualification of hydrogenated amorphous silicon sensors on flexible substrate

Mikaël Martino, Sylvain Dunand, Nicolas Würsch, Luca Massimiliano Antognini, Matthew James Large

Hydrogenated amorphous silicon (a-Si:H) is a well known material for its radiation resistance and for the possibility of deposition on flexible substrates like Polyimide (PI), polyethylene terephthalate (PET) or polyethylene naphthalate (PEN). Due to the p ...

IEEE2023

Neutron irradiation of Hydrogenated Amorphous Silicon p-i-n diodes and charge selective contacts detectors

Sylvain Dunand, Nicolas Würsch

Hydrogenated amorphous silicon is a well-known detector material for its radiation resistance. For this reason it has been used in particle beam flux measurements and in solar panels designed for space applications. This study concern 10 & mu;m thickness, ...

2023

Hydrogenated amorphous silicon high flux x-ray detectors for synchrotron microbeam radiation therapy

Sylvain Dunand, Nicolas Würsch, Giulia Rossi, Matthew James Large

Objective. Microbeam radiation therapy (MRT) is an alternative emerging radiotherapy treatment modality which has demonstrated effective radioresistant tumour control while sparing surrounding healthy tissue in preclinical trials. This apparent selectivity ...

IOP Publishing Ltd2023

A hydrogenated amorphous silicon detector for Space Weather applications

Sylvain Dunand, Nicolas Würsch, Jonathan Emanuel Thomet, Luca Massimiliano Antognini, Matthew James Large

The characteristics of a hydrogenated amorphous silicon (a-Si:H) detector are presented here for monitoring in space solar flares and the evolution of strong to extreme energetic proton events. The importance and the feasibility to extend the proton measur ...

SPRINGER2023

High-Resolution Photoemission Study of Neutron-Induced Defects in Amorphous Hydrogenated Silicon Devices

Sylvain Dunand, Nicolas Würsch, Giulia Rossi, Matthew James Large

In this paper, by means of high-resolution photoemission, soft X-ray absorption and atomic force microscopy, we investigate, for the first time, the mechanisms of damaging, induced by neutron source, and recovering (after annealing) of p-i-n detector devic ...

MDPI2022

Plastic and Elastic Strain Fields in GaAs/Si Core-Shell Nanowires

Christophe Ballif, Anna Fontcuberta i Morral, Martin Heiss, Sylvain Dunand, Sonia Conesa Boj, Eleonora Russo

Thanks to their unique morphology, nanowires have enabled integration of materials in a way that was not possible before with thin film technology. In turn, this opens new avenues for applications in the areas of energy harvesting, electronics, and optoele ...

American Chemical Society2014

Hybrid axial and radial Si-GaAs heterostructures in nanowires

Christophe Ballif, Anna Fontcuberta i Morral, Martin Heiss, Sylvain Dunand, Daniel Rüffer, Sonia Conesa Boj, Eleonora Russo

Hybrid structures are formed from materials of different families. Traditionally, group IV and III-V semiconductors have not been integrated together in the same device or application. In this work we present a new approach for obtaining Si-GaAs hybrid het ...

Royal Society of Chemistry2013

Amorphous silicon based betavoltaic devices

Christophe Ballif, Sylvain Dunand, Yannick Samuel Riesen, Andrea Franco

Hydrogenated amorphous silicon betavoltaic devices are studied both by simulation and experimentally. Devices exhibiting a power density of 0.1 μW/cm2 upon Tritium exposure were fabricated. However, a significant degradation of the performance is taking pl ...

2013

Micro-Channel Plate Detectors Based on Hydrogenated Amorphous Silicon

Christophe Ballif, Sylvain Dunand, Matthieu Despeisse, François Eric Powolny

A new type of micro-channel plate detector based on hydrogenated amorphous silicon is proposed which overcomes the fabrication and performance issues of glass or bulk silicon ones. This new type of detectors consists in 80-100 μm thick layers of amorphous ...

2010