Giulio Pellegrini | CSIC (Consejo Superior de Investigaciones Científicas-Spanish National Research Council) (original) (raw)

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Papers by Giulio Pellegrini

Research paper thumbnail of Future trends of 3D silicon sensors

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2013

ABSTRACT Vertex detectors for the next LHC experiments upgrades will need to have low mass while ... more ABSTRACT Vertex detectors for the next LHC experiments upgrades will need to have low mass while at the same time be radiation hard and with sufficient granularity to fulfil the physics challenges of the next decade. Based on the gained experience with 3D silicon sensors for the ATLAS IBL project and the on-going developments on light materials, interconnectivity and cooling, this paper will discuss possible solutions to these requirements.

Research paper thumbnail of A fourfold segmented silicon strip sensor with read-out at the edges

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2015

ABSTRACT

Research paper thumbnail of Ultra-Thin 3-D Detector: Charge Collection Characterization and Application for Microdosimetry

IEEE Transactions on Nuclear Science, 2014

Research paper thumbnail of Special bump bonding technique for silicon pixel detectors

Nuclear Instruments and Methods in Physics Research Section a Accelerators Spectrometers Detectors and Associated Equipment, Jun 1, 2007

This paper presents a high-density bumping technique based on electrodeposition of the bump mater... more This paper presents a high-density bumping technique based on electrodeposition of the bump materials. The idea of such technique is to allow the packaging of densely populated chips such as array pixel detectors. Silicon pixel detector dummies have been designed and fabricated at CNM in order to evaluate the technique developed. Special test structures have been included in these dummies to evaluate the final yield of the process developed at CNM. The foreseen applications are Medical Imaging and X-ray systems. The new bumping technique developed will greatly improve the simplicity and the cost of the packaging process.

Research paper thumbnail of Radiation detector, method of manufacturing a radiation detector and use of the detector for measuring radiation

Research paper thumbnail of Technology development of 3D detectors for high energy physics and medical imaging

Various fabrications routes to create '3D'detectors hav... more Various fabrications routes to create '3D'detectors have been investigated and the electrical characteristics of these structures have been compared to simulations. The geometry of the detectors is hexagonal with a central anode surrounded by six cathode contacts. A ...

Research paper thumbnail of Radiation Hardness Tests of Double-Sided 3D Detectors

3D detectors are potentially useful for future highluminosity colliders such as the SLHC, due to ... more 3D detectors are potentially useful for future highluminosity colliders such as the SLHC, due to their radiation hardness. IMB-CNM have fabricated a set of 3D detectors that use a "double sided" 3D structure, where the two sets of electrode columns are etched from opposite sides of the substrate, and do not pass through the full substrate thickness. Simulations show that this structure should give similar radiation hardness to the standard full-3D structure. Two sets of devices have been successfully tested; Medipix2 pixel detectors and strip detectors coupled to LHC-speed readout electronics. The unirradiated 3D Medipix2 detectors have shown extremely low operating voltages and low charge sharing in tests with X-rays, and the strips have shown relatively high charge collection at high levels of radiation damage.

Research paper thumbnail of Direct charge sharing observation in single-photon-counting pixel detector

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment

In photon-counting imaging devices, charge sharing can limit the detector spatial resolution and ... more In photon-counting imaging devices, charge sharing can limit the detector spatial resolution and contrast, as multiple counts can be induced in adjacent pixels as a result of the spread of the charge cloud generated from a single X-ray photon of high energy in the detector bulk. Although debated for a long time, the full impact of charge sharing has not been completely assessed. In this work, the importance of charge sharing in pixellated CdTe and silicon detectors is studied by exposing imaging devices to different low activity sources. These devices are made of Si and CdTe pixel detector bump-bonded to Medipix2 single-photon-counting chips with a 55 mm pixel pitch. We will show how charge sharing affects the spatial detector resolution depending on incident particle type (alpha, beta and gamma), detector bias voltage and read-out chip threshold. This study will give an insight on the impact on the design and operation of pixel detectors coupled to photon-counting devices for imaging applications. r

Research paper thumbnail of 3D cylindrical silicon microdosimeters: fabrication, simulation and charge collection study

Journal of Instrumentation, 2015

Research paper thumbnail of Radiation damage of SiGe HBT Technologies at different bias configurations

SiGe BiCMOS technologies are being proposed for the Front-end readout of the detectors in the mid... more SiGe BiCMOS technologies are being proposed for the Front-end readout of the detectors in the middle region of the ATLAS-Upgrade. The radiation hardness of the SiGe bipolar transistors is being assessed for this application through irradiations with different particles. Biasing conditions during irradiation of bipolar transistors or circuits have an influence on the damage and there is a risk of erroneous results. We have performed several irradiation experiments of SiGe devices from IHP in different bias conditions. We have observed a systematic trend in gamma irradiations, showing a smaller damage in transistors irradiated biased compared to shorted or floating terminals.

Research paper thumbnail of Ionizing radiation detector sensitive to the 2d position

Research paper thumbnail of High-Performance Magneto-Optic Surface Plasmon Resonance Sensor Design: An Optimization Approach

Plasmonics

High-performance intensity-interrogated magneto-optic surface plasmon resonance (MOSPR) sensors a... more High-performance intensity-interrogated magneto-optic surface plasmon resonance (MOSPR) sensors are designed by a multi-objective optimization approach. Designed devices show bulk refractive index sensitivity 1 order of magnitude larger than the current state of the art, while the design procedure allows to chose an appropriate trade-off between sensor performance and ease of fabrica-tion. Straightforward guidelines for the sensor design and fabrication emerge from the optimization process, indicat-ing that minimization of the optical losses takes precedence on the maximization of the magneto-optical modulation.

Research paper thumbnail of Detection of Early Markers in Mammography Project

Research paper thumbnail of Charge sharing measurements of pixilated CdTe using Medipix-II chip

Proceedings of the 21st IEEE Instrumentation and Measurement Technology Conference (IEEE Cat. No.04CH37510), 2004

One important consideration of the design and the operation of pixilated detector is the ratio of... more One important consideration of the design and the operation of pixilated detector is the ratio of the pixel size to the thickness of the detector. When the e-h pairs are generated and the charge drifts toward the pixel electrodes under the influence of the bias field, the charge spreads laterally making it possible that the cloud of charge reaches a cluster of pixels instead of one single pixel. The amount of the charge spread is directly related to the drift time, which strongly depends on the carrier mobility and distance traveled by the carriers. This study has general impact on the design of pixilated detector; however its impact on the design and the operation of pixilated detector coupled to photon counting electronics is more profound. The results imply that designing a Cd(Zn)Te detector with very small pixel size, say 25 µm and a detector 1 mm thick, is unrealistic because in reality such intrinsic fine spatial resolution can not be attained in the corresponding image due charge sharing.

Research paper thumbnail of Silicon-based three-dimensional microstructures for radiation dosimetry in hadrontherapy

Applied Physics Letters, 2015

ABSTRACT

Research paper thumbnail of CdTe/CZT pixel detector for gamma-ray spectrometry with imaging and polarimetry capability in astrophysics

Gamma-ray astrophysics in the MeV energy range plays a crucial role for the understanding of many... more Gamma-ray astrophysics in the MeV energy range plays a crucial role for the understanding of many exciting cosmic phenomena such as stellar explosions or cosmic accelerators (e.g., Supernovae, Novae, Supernova Remants (SNRs), Gamma-Ray Bursts (GRBs), Pulsars, etc). Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) are very attractive materials for gamma-ray detection, which have demonstrated a great potential onboard current space missions (such as IBIS/INTEGRAL and BAT/SWIFT). However, the energy coverage of these instruments has been limited up to a few hundred keV, and there has not been yet a dedicated instrument for polarimetry. Our technological activities aim to develop a gamma-ray spectrometer based on Cd(Zn)Te detectors, with imaging and polarimetry capability for astrophysical applications, in the energy range from a few hundred keV up to a few MeV. Within this framework, a gamma-ray polarimeter based on pixelated Cd(Zn)Te detectors in planar-transverse-field (P...

Research paper thumbnail of Technology Development of 3D Detectors for Medical Imaging

Fabrication routes to realising '3D' detectors in gallium arsenide (GaAs) have been inves... more Fabrication routes to realising '3D' detectors in gallium arsenide (GaAs) have been investigated and their electrical characteristics measured. The geometry of the detector is hexagonal with a central anode surrounded by six cathode contacts. This geometry gives a uniform electric field with the maximum drift and depletion distance set by electrode spacings rather than detector thickness. The advantages of this

Research paper thumbnail of 10μm thin transmissive photodiode produced by ALBA Synchrotron and IMB-CNM-CSIC

Journal of Instrumentation, 2015

ABSTRACT Thin silicon photodiodes are common X-ray beam diagnosis devices at synchrotron faciliti... more ABSTRACT Thin silicon photodiodes are common X-ray beam diagnosis devices at synchrotron facilities. Here we present a new device featuring an extremely thin layer that allows X-ray transmission over 90% for energies above 10 keV. The diode has a radiation-hard silicon junction with silicon dioxide passivation and a protective entrance window. These outstanding features make this device suited for diagnostic applications in X-ray synchrotron beamlines. Hereby preliminary results of X-ray transmission, responsivity and uniformity are presented.

Research paper thumbnail of Journal Article

The ABCD3TA is a 128-channel ASIC with binary architecture for the readout of silicon strip parti... more The ABCD3TA is a 128-channel ASIC with binary architecture for the readout of silicon strip particle detectors in the Semiconductor Tracker of the ATLAS experiment at the Large Hadron Collider (LHC). The chip comprises fast front-end and amplitude discriminator circuits using bipolar devices, a binary pipeline for first level trigger latency, a second level derandomising buffer and data compression circuitry based on CMOS devices. It has been designed and fabricated in a BiCMOS radiation resistant process. Extensive testing of the ABCD3TA chips assembled into detector modules show that the design meets the specifications and maintains the required performance after irradiation up to a total ionising dose of 10 Mrad and a 1-MeV neutron equivalent fluence of 2×1014 n/cm2, corresponding to 10 years of operation of the LHC at its design luminosity. Wafer screening and quality assurance procedures have been developed and implemented in large volume production to ensure that the chips ass...

Research paper thumbnail of Characterisation of Glasgow/CNM Double-Sided 3D Sensors

Physics Procedia, 2012

ABSTRACT 3D detectors are proposed as an alternative to planar silicon technology to withstand th... more ABSTRACT 3D detectors are proposed as an alternative to planar silicon technology to withstand the high radiation environments in planned future high energy physics experiments. Here we review the characterization of double-sided 3D detectors designed and built at CNM and the University of Glasgow. A non-irradiated sensor is characterized in a pion test-beamutilizing the Timepix telescope. The charge collection and detection efficiency across the unit pixel are shown. Area of inefficiency can be found at the columnar electrodes at perpendicular angles of beam incidence while the pixels are shown to be fully efficient at angles greater than ten degrees. A reduction in charge sharing compared to the planar technology is also demonstrated. Charge collection studies on irradiated devices with a Sr-90 source show higher charge collection efficiency for 3D over planar sensors at significantly lower applied bias. The sub-pixel response is probed by a micro-focused laser beam demonstrating areas of charge multiplication at high bias voltages. (C) 2012 Published by Elsevier B. V. Selection and/or peer review under responsibility of the organizing committee for TIPP 11.

Research paper thumbnail of Future trends of 3D silicon sensors

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2013

ABSTRACT Vertex detectors for the next LHC experiments upgrades will need to have low mass while ... more ABSTRACT Vertex detectors for the next LHC experiments upgrades will need to have low mass while at the same time be radiation hard and with sufficient granularity to fulfil the physics challenges of the next decade. Based on the gained experience with 3D silicon sensors for the ATLAS IBL project and the on-going developments on light materials, interconnectivity and cooling, this paper will discuss possible solutions to these requirements.

Research paper thumbnail of A fourfold segmented silicon strip sensor with read-out at the edges

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2015

ABSTRACT

Research paper thumbnail of Ultra-Thin 3-D Detector: Charge Collection Characterization and Application for Microdosimetry

IEEE Transactions on Nuclear Science, 2014

Research paper thumbnail of Special bump bonding technique for silicon pixel detectors

Nuclear Instruments and Methods in Physics Research Section a Accelerators Spectrometers Detectors and Associated Equipment, Jun 1, 2007

This paper presents a high-density bumping technique based on electrodeposition of the bump mater... more This paper presents a high-density bumping technique based on electrodeposition of the bump materials. The idea of such technique is to allow the packaging of densely populated chips such as array pixel detectors. Silicon pixel detector dummies have been designed and fabricated at CNM in order to evaluate the technique developed. Special test structures have been included in these dummies to evaluate the final yield of the process developed at CNM. The foreseen applications are Medical Imaging and X-ray systems. The new bumping technique developed will greatly improve the simplicity and the cost of the packaging process.

Research paper thumbnail of Radiation detector, method of manufacturing a radiation detector and use of the detector for measuring radiation

Research paper thumbnail of Technology development of 3D detectors for high energy physics and medical imaging

Various fabrications routes to create '3D'detectors hav... more Various fabrications routes to create '3D'detectors have been investigated and the electrical characteristics of these structures have been compared to simulations. The geometry of the detectors is hexagonal with a central anode surrounded by six cathode contacts. A ...

Research paper thumbnail of Radiation Hardness Tests of Double-Sided 3D Detectors

3D detectors are potentially useful for future highluminosity colliders such as the SLHC, due to ... more 3D detectors are potentially useful for future highluminosity colliders such as the SLHC, due to their radiation hardness. IMB-CNM have fabricated a set of 3D detectors that use a "double sided" 3D structure, where the two sets of electrode columns are etched from opposite sides of the substrate, and do not pass through the full substrate thickness. Simulations show that this structure should give similar radiation hardness to the standard full-3D structure. Two sets of devices have been successfully tested; Medipix2 pixel detectors and strip detectors coupled to LHC-speed readout electronics. The unirradiated 3D Medipix2 detectors have shown extremely low operating voltages and low charge sharing in tests with X-rays, and the strips have shown relatively high charge collection at high levels of radiation damage.

Research paper thumbnail of Direct charge sharing observation in single-photon-counting pixel detector

Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment

In photon-counting imaging devices, charge sharing can limit the detector spatial resolution and ... more In photon-counting imaging devices, charge sharing can limit the detector spatial resolution and contrast, as multiple counts can be induced in adjacent pixels as a result of the spread of the charge cloud generated from a single X-ray photon of high energy in the detector bulk. Although debated for a long time, the full impact of charge sharing has not been completely assessed. In this work, the importance of charge sharing in pixellated CdTe and silicon detectors is studied by exposing imaging devices to different low activity sources. These devices are made of Si and CdTe pixel detector bump-bonded to Medipix2 single-photon-counting chips with a 55 mm pixel pitch. We will show how charge sharing affects the spatial detector resolution depending on incident particle type (alpha, beta and gamma), detector bias voltage and read-out chip threshold. This study will give an insight on the impact on the design and operation of pixel detectors coupled to photon-counting devices for imaging applications. r

Research paper thumbnail of 3D cylindrical silicon microdosimeters: fabrication, simulation and charge collection study

Journal of Instrumentation, 2015

Research paper thumbnail of Radiation damage of SiGe HBT Technologies at different bias configurations

SiGe BiCMOS technologies are being proposed for the Front-end readout of the detectors in the mid... more SiGe BiCMOS technologies are being proposed for the Front-end readout of the detectors in the middle region of the ATLAS-Upgrade. The radiation hardness of the SiGe bipolar transistors is being assessed for this application through irradiations with different particles. Biasing conditions during irradiation of bipolar transistors or circuits have an influence on the damage and there is a risk of erroneous results. We have performed several irradiation experiments of SiGe devices from IHP in different bias conditions. We have observed a systematic trend in gamma irradiations, showing a smaller damage in transistors irradiated biased compared to shorted or floating terminals.

Research paper thumbnail of Ionizing radiation detector sensitive to the 2d position

Research paper thumbnail of High-Performance Magneto-Optic Surface Plasmon Resonance Sensor Design: An Optimization Approach

Plasmonics

High-performance intensity-interrogated magneto-optic surface plasmon resonance (MOSPR) sensors a... more High-performance intensity-interrogated magneto-optic surface plasmon resonance (MOSPR) sensors are designed by a multi-objective optimization approach. Designed devices show bulk refractive index sensitivity 1 order of magnitude larger than the current state of the art, while the design procedure allows to chose an appropriate trade-off between sensor performance and ease of fabrica-tion. Straightforward guidelines for the sensor design and fabrication emerge from the optimization process, indicat-ing that minimization of the optical losses takes precedence on the maximization of the magneto-optical modulation.

Research paper thumbnail of Detection of Early Markers in Mammography Project

Research paper thumbnail of Charge sharing measurements of pixilated CdTe using Medipix-II chip

Proceedings of the 21st IEEE Instrumentation and Measurement Technology Conference (IEEE Cat. No.04CH37510), 2004

One important consideration of the design and the operation of pixilated detector is the ratio of... more One important consideration of the design and the operation of pixilated detector is the ratio of the pixel size to the thickness of the detector. When the e-h pairs are generated and the charge drifts toward the pixel electrodes under the influence of the bias field, the charge spreads laterally making it possible that the cloud of charge reaches a cluster of pixels instead of one single pixel. The amount of the charge spread is directly related to the drift time, which strongly depends on the carrier mobility and distance traveled by the carriers. This study has general impact on the design of pixilated detector; however its impact on the design and the operation of pixilated detector coupled to photon counting electronics is more profound. The results imply that designing a Cd(Zn)Te detector with very small pixel size, say 25 µm and a detector 1 mm thick, is unrealistic because in reality such intrinsic fine spatial resolution can not be attained in the corresponding image due charge sharing.

Research paper thumbnail of Silicon-based three-dimensional microstructures for radiation dosimetry in hadrontherapy

Applied Physics Letters, 2015

ABSTRACT

Research paper thumbnail of CdTe/CZT pixel detector for gamma-ray spectrometry with imaging and polarimetry capability in astrophysics

Gamma-ray astrophysics in the MeV energy range plays a crucial role for the understanding of many... more Gamma-ray astrophysics in the MeV energy range plays a crucial role for the understanding of many exciting cosmic phenomena such as stellar explosions or cosmic accelerators (e.g., Supernovae, Novae, Supernova Remants (SNRs), Gamma-Ray Bursts (GRBs), Pulsars, etc). Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) are very attractive materials for gamma-ray detection, which have demonstrated a great potential onboard current space missions (such as IBIS/INTEGRAL and BAT/SWIFT). However, the energy coverage of these instruments has been limited up to a few hundred keV, and there has not been yet a dedicated instrument for polarimetry. Our technological activities aim to develop a gamma-ray spectrometer based on Cd(Zn)Te detectors, with imaging and polarimetry capability for astrophysical applications, in the energy range from a few hundred keV up to a few MeV. Within this framework, a gamma-ray polarimeter based on pixelated Cd(Zn)Te detectors in planar-transverse-field (P...

Research paper thumbnail of Technology Development of 3D Detectors for Medical Imaging

Fabrication routes to realising '3D' detectors in gallium arsenide (GaAs) have been inves... more Fabrication routes to realising '3D' detectors in gallium arsenide (GaAs) have been investigated and their electrical characteristics measured. The geometry of the detector is hexagonal with a central anode surrounded by six cathode contacts. This geometry gives a uniform electric field with the maximum drift and depletion distance set by electrode spacings rather than detector thickness. The advantages of this

Research paper thumbnail of 10μm thin transmissive photodiode produced by ALBA Synchrotron and IMB-CNM-CSIC

Journal of Instrumentation, 2015

ABSTRACT Thin silicon photodiodes are common X-ray beam diagnosis devices at synchrotron faciliti... more ABSTRACT Thin silicon photodiodes are common X-ray beam diagnosis devices at synchrotron facilities. Here we present a new device featuring an extremely thin layer that allows X-ray transmission over 90% for energies above 10 keV. The diode has a radiation-hard silicon junction with silicon dioxide passivation and a protective entrance window. These outstanding features make this device suited for diagnostic applications in X-ray synchrotron beamlines. Hereby preliminary results of X-ray transmission, responsivity and uniformity are presented.

Research paper thumbnail of Journal Article

The ABCD3TA is a 128-channel ASIC with binary architecture for the readout of silicon strip parti... more The ABCD3TA is a 128-channel ASIC with binary architecture for the readout of silicon strip particle detectors in the Semiconductor Tracker of the ATLAS experiment at the Large Hadron Collider (LHC). The chip comprises fast front-end and amplitude discriminator circuits using bipolar devices, a binary pipeline for first level trigger latency, a second level derandomising buffer and data compression circuitry based on CMOS devices. It has been designed and fabricated in a BiCMOS radiation resistant process. Extensive testing of the ABCD3TA chips assembled into detector modules show that the design meets the specifications and maintains the required performance after irradiation up to a total ionising dose of 10 Mrad and a 1-MeV neutron equivalent fluence of 2×1014 n/cm2, corresponding to 10 years of operation of the LHC at its design luminosity. Wafer screening and quality assurance procedures have been developed and implemented in large volume production to ensure that the chips ass...

Research paper thumbnail of Characterisation of Glasgow/CNM Double-Sided 3D Sensors

Physics Procedia, 2012

ABSTRACT 3D detectors are proposed as an alternative to planar silicon technology to withstand th... more ABSTRACT 3D detectors are proposed as an alternative to planar silicon technology to withstand the high radiation environments in planned future high energy physics experiments. Here we review the characterization of double-sided 3D detectors designed and built at CNM and the University of Glasgow. A non-irradiated sensor is characterized in a pion test-beamutilizing the Timepix telescope. The charge collection and detection efficiency across the unit pixel are shown. Area of inefficiency can be found at the columnar electrodes at perpendicular angles of beam incidence while the pixels are shown to be fully efficient at angles greater than ten degrees. A reduction in charge sharing compared to the planar technology is also demonstrated. Charge collection studies on irradiated devices with a Sr-90 source show higher charge collection efficiency for 3D over planar sensors at significantly lower applied bias. The sub-pixel response is probed by a micro-focused laser beam demonstrating areas of charge multiplication at high bias voltages. (C) 2012 Published by Elsevier B. V. Selection and/or peer review under responsibility of the organizing committee for TIPP 11.