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Jerome Baudot,
Auguste Besson,
Gilles Claus,
Wojciech Dulinski,
Andrei Dorokhov,
Mathieu Goffe,
Christine Hu-Guo,
Levente Molnar,
Xitzel Sanchez-Castro,
Serhyi Senyukov, Marc Winter
[show abstract]
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ABSTRACT: CMOS Pixel Sensors tend to become relevant for a growing spectrum of charged
particle detection instruments. This comes mainly from their high granularity
and low material budget. However, several potential applications require a
higher read-out speed and radiation tolerance than those achieved with
available devices based on a 0.35 micrometers feature size technology. This
paper shows preliminary test results of new prototype sensors manufactured in a
0.18 micrometers process based on a high resistivity epitaxial layer of
sizeable thickness. Grounded on these observed performances, we discuss a
development strategy over the coming years to reach a full scale sensor
matching the specifications of the upgraded version of the Inner Tracking
System (ITS) of the ALICE experiment at CERN, for which a sensitive area of up
to about 10 square meters may be equipped with pixel sensors.
05/2013;
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ABSTRACT: The apparatus of the ALICE experiment at CERN will be upgraded in 2017/18
during the second long shutdown of the LHC (LS2). A major motivation for this
upgrade is to extend the physics reach for charmed and beauty particles down to
low transverse momenta. This requires a substantial improvement of the spatial
resolution and the data rate capability of the ALICE Inner Tracking System
(ITS). To achieve this goal, the new ITS will be equipped with 50 um thin CMOS
Pixel Sensors (CPS) covering either the 3 innermost layers or all the 7 layers
of the detector. The CPS being developed for the ITS upgrade at IPHC
(Strasbourg) is derived from the MIMOSA 28 sensor realised for the STAR-PXL at
RHIC in a 0.35 um CMOS process. In order to satisfy the ITS upgrade
requirements in terms of readout speed and radiation tolerance, a CMOS process
with a reduced feature size and a high resistivity epitaxial layer should be
exploited. In this respect, the charged particle detection performance and
radiation hardness of the TowerJazz 0.18 um CMOS process were studied with the
help of the first prototype chip MIMOSA 32. The beam tests performed with
negative pions of 120 GeV/c at the CERN-SPS allowed to measure a
signal-to-noise ratio (SNR) for the non-irradiated chip in the range between 22
and 32 depending on the pixel design. The chip irradiated with the combined
dose of 1 MRad and 10^13 n_eq/cm^2 was observed to yield a SNR ranging between
11 and 23 for coolant temperatures varying from 15 C to 30 C. These SNR values
were measured to result in particle detection efficiencies above 99.5% and 98%
before and after irradiation respectively. These satisfactory results allow to
validate the TowerJazz 0.18 um CMOS process for the ALICE ITS upgrade.
01/2013;
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Marc Winter,
Jerome Baudot,
Auguste Besson,
Gilles Claus,
Andrei Dorokhov,
Mathieu Goffe,
Christine Hu-Guo,
Frederic Morel,
Isabelle Valin,
Georgios Voutsinas,
Liang Zhang
[show abstract]
[hide abstract]
ABSTRACT: CMOS Pixel Sensors are making steady progress towards the specifications of
the ILD vertex detector. Recent developments are summarised, which show that
these devices are close to comply with all major requirements, in particular
the read-out speed needed to cope with the beam related background. This
achievement is grounded on the double- sided ladder concept, which allows
combining signals generated by a single particle in two different sensors, one
devoted to spatial resolution and the other to time stamp, both assembled on
the same mechanical support. The status of the development is overviewed as
well as the plans to finalise it using an advanced CMOS process.
03/2012;
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[show abstract]
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ABSTRACT: The impact of the incoherent electron-positron pairs from beamstrahlung on the occupancy of the vertex detector (VXD) for the International Large Detector concept (ILD) has been studied, based on the standard ILD simulation tools. The occupancy was evaluated for two substantially different sensor technology in order to estimate the importance of the latter. The influence of an anti-DID field removing backscattered electrons has also been studied.
03/2009;
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Marc Winter,
Jerome Baudot,
Auguste Besson,
Claude Colledani,
Yavuz Degerli,
Rita De Masi,
Andrei Dorokhov,
Guy Doziere,
Wojciech Dulinski,
Marie Gelin,
Fabrice Guilloux,
Abdelkader Himmi,
Christine Hu-Guo,
Frederic Morel,
Fabienne Orsini,
Isabelle Valin,
Georgios Voutsinas
[show abstract]
[hide abstract]
ABSTRACT: Swift, high resolution CMOS pixel sensors are being developed for the ILC vertex detector, aiming to allow approaching the interaction point very closely. A major issue is the time resolution of the sensors needed to deal with the high occupancy generated by the beam related background. A 128x576 pixel sensor providing digitised outputs at a read-out time of 92.5 us, was fabricated in 2008 within the EU project EUDET, and tested with charged particles at the CERN-SPS. Its prominent performances in terms of noise, detection efficiency versus fake hit rate, spatial resolution and radiation tolerance are overviewed. They validate the sensor architecture.
03/2009;
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Wojciech Dulinski,
Auguste Besson,
Gilles Claus,
Claude Colledani,
Grzegorz Deptuch,
Michael Deveaux,
Goetz Gaycken,
Damien Grandjean,
Abdelkader Himmi,
Christine Hu,
Kimmo Jaaskeleinen,
Michal Szelezniak,
Isabelle Valin, Marc Winter
[show abstract]
[hide abstract]
ABSTRACT: CMOS Monolithic Active Pixel Sensors (MAPS) provide an attractive solution for high precision tracking of minimum ionizing particles. In these devices, a thin, moderately doped, undepleted silicon layer is used as the active detector volume with the readout electronics implemented on top of it. Recently, a new MAPS prototype was fabricated using the AMS 0.35 mum OPTO process, featuring a thick epitaxial layer. A systematic study of tracking performance of that prototype using high-energy particle beam is presented in this work. Noise performance, signal amplitude from minimum ionizing particles, detection efficiency, spurious hit suppression and spatial resolution are shown as a function of the readout pitch and the charge collecting diode size. A test array with a novel readout circuitry was also fabricated and tested. Each pixel circuit consists of a front-end voltage amplifier, capacitively coupled to the charge collecting diode, followed by two analog memory cells. This architecture implements an on-pixel correlated double sampling method, allowing for optimization of integration independently of full frame readout time and strongly reduces the pixel-to-pixel output signal dispersion. First measurements using this structure are also presented
IEEE Transactions on Nuclear Science 03/2007; · 1.45 Impact Factor
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ABSTRACT: The thesis has been completed within the ATLAS experiment at CERN, between 2006 and 2009, and has been done during the last years of construction of the LHC. After an introduction in particle physics, the thesis describes the ATLAS experiment with its inner detector and TRT. First, work on the TRT simulation has been done, concerning the geometry, as well as some estimates and measurements of the TRT weight. The detector performances are studied in a second part, to measure the electrons energy and momentum. Using some E/p distributions, a work on the determination of the amount of material and the residual misalignments is presented. In the third part, an estimate of the systematic uncertainty due to the acceptance corrections on the $W\to e\nu$ and $Z \to ee$ cross-section measurements is given. The last part contains an analysis of cosmic ray data in the TRT. The first results on the wire-by-wire alignment are presented.
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Auguste Besson,
Gilles Claus,
Claude Colledani,
Yavuz Degerli,
Grzegorz Deptuch,
Michael Deveaux,
Wojciech Dulinski,
Nicolas Fourches,
Mathieu Goffe,
Damien Grandjean, [......],
Kimmo Jaaskelainen,
Yan Li,
Pierre Lutz,
Fabienne Orsini,
Michel Pellicioli,
Emanuele Scopelliti,
Alexandre Shabetai,
Michal Szelezniak,
Isabelle Valin, Marc Winter
[show abstract]
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ABSTRACT: The physics programme at the International Linear Collider (ILC) calls for a vertex detector (VD) providing unprecedented flavour tagging performances, especially for c-quarks and τ leptons. This requirement makes a very granular, thin and multi-layer VD installed very close to the interaction region mandatory. Additional constraints, mainly on read-out speed and radiation tolerance, originate from the beam background, which governs the occupancy and the radiation level the detector should be able to cope with. CMOS sensors are being developed to fulfil these requirements. This report addresses the ILC requirements (highly related to beamstrahlung), the main advantages and features of CMOS sensors, the demonstrated performances and the specific aspects of a VD based on this technology. The status of the main R&D directions (radiation tolerance, thinning procedure and read-out speed) are also presented.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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ABSTRACT: A backside illuminated, monolithic CMOS pixel sensor for direct detection of low energy electrons has been developed and is proposed as an active element for a non-destructive hadron beam monitor. In this application, the device is used as an imager of secondary electrons emitted from an aluminium foil of sub-micrometer thick intersecting the beam and accelerated in an electrostatic field to ∼20–30 keV energy. The sensitivity to these electron energies (a few microns range in silicon) is obtained by back-thinning the detector, fabricated in the form of standard VLSI chip, down to the radiation sensitive epitaxial layer. The original thinning procedure was applied for processing of a large area, one million pixels prototype. The prototype has been tested using low-energy electrons inside an HPD structure. Tests results proving the device imaging capabilities of such a radiation are presented.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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Michal Szelezniak,
Auguste Besson,
Gilles Claus,
Claude Colledani,
Yavuz Degerli,
Grzegorz Deptuch,
Michael Deveaux,
Andrei Dorokhov,
Wojciech Dulinski,
Nicolas Fourches, [......],
Abdelkader Himmi,
Christine Hu,
Kimmo Jaaskelainen,
Yan Li,
Pierre Lutz,
Fabienne Orsini,
Michel Pellicioli,
Alexandre Shabetai,
Isabelle Valin, Marc Winter
[show abstract]
[hide abstract]
ABSTRACT: Several development directions intended to adapt and optimize monolithic active pixel sensors for specific applications are presented in this work. The first example, compatible with the STAR microvertex upgrade, is based on a simple two-transistor pixel circuitry. It is suited for a long integration time, room-temperature operation and minimum power dissipation. In another approach for this application, a specific readout method is proposed, allowing optimization of the integration time independently of the full frame-readout time. The circuit consists of an in-pixel front-end voltage amplifier, with a gain on the order of five, followed by two analog memory cells. The extended version of this scheme, based on the implementation of more memory cells per pixel, is the solution considered for the outer layers of a microvertex detector at the international linear collider. For the two innermost layers, a circuit allowing fast frame scans together with on-line, on-chip data sparsification is proposed. The first results of this prototype demonstrate that the fixed pattern dispersion is reduced below a noise level of 15 e−, allowing the use of a single comparator or a low-resolution ADC per pixel column. A common element for most of the mentioned readout schemes is a low-noise, low power consumption, layout efficient in-pixel amplifier. A review of possible solutions for this element together with some experimental results is presented.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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[show abstract]
[hide abstract]
ABSTRACT: The increasing need of high performance flavour tagging capabilities in parti-cle physics experiments has triggered the development of a novel -fully integrated -silicon pixel detector, called Monolithic Active Pixel Sensor (i.e. MAPS). Similar to CMOS visi-ble light imagers, the first MAPS prototypes adapted to the detection of minimum ionising particles (i.e. mip) were designed and fabricated in standard CMOS technology. Their tests with relativistic charged particles demonstrate that the sensors detect mips with very high efficiency and signal-to-noise ratio and provide excellent spatial resolution. The main aspects of these results, which establish the adequacy of the technology for charged particle tracking, are summarised in this paper, together with preliminary results on its radiation hardness. An outlook on the R&D started to provide fully integrated building blocks of future vertex detectors is also provided.
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[show abstract]
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ABSTRACT: Monolithic Active Pixel Sensors (MAPS) for charged particle tracking consist of a novel detection technique, where the detecting element is inseparable from the readout electronics, both of them being integrated on the same substrate. As radiation hardness is mandatory for most applications, the resistance of a MAPS-detector design against irradiation is currently subject to intensive studies. Parameters such as charge-to-voltage conversion gain, pixel leakage current, noise and charge collection efficiency are investigated as a function of integrated dose. First- and second-generation prototypes, MIMOSA1 and MIMOSA2, were irradiated with up to 1013 neq/cm2 for this purpose. Preliminary results are presented. The charge-to-voltage conversion gain and noise were found to be almost stable and the leakage current was observed to raise moderately. On the other hand, the pixel charge collected came out to be substantially affected by the highest fluences considered.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
