Showing papers by "Celeste Fleta published in 2012"
TL;DR: In this article, the ATLAS Collaboration will upgrade its semiconductor pixel tracking detector with a new Insertable B-layer (IBL) between the existing pixel detector and the vacuum pipe of the Large Hadron Collider.
Abstract: The ATLAS Collaboration will upgrade its semiconductor pixel tracking detector with a new Insertable B-layer (IBL) between the existing pixel detector and the vacuum pipe of the Large Hadron Collider. The extreme operating conditions at this location have necessitated the development of new radiation hard pixel sensor technologies and a new front-end readout chip, called the FE-I4. Planar pixel sensors and 3D pixel sensors have been investigated to equip this new pixel layer, and prototype modules using the FE-I4A have been fabricated and characterized using 120 GeV pions at the CERN SPS and 4 GeV positrons at DESY, before and after module irradiation. Beam test results are presented, including charge collection efficiency, tracking efficiency and charge sharing.
154 citations
01 Dec 2012-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the insertion of a new layer as close as 3.4 cm from the proton beams inside the existing pixel layers of the ATLAS experiment has been discussed, where the detector proximity to the interaction point will require new radiation hard technologies for both sensors and front end electronics.
Abstract: 3D silicon sensors, where electrodes penetrate the silicon substrate fully or partially, have successfully been fabricated in different processing facilities in Europe and USA. The key to 3D fabrication is the use of plasma micro-machining to etch narrow deep vertical openings allowing dopants to be diffused in and form electrodes of pin junctions. Similar openings can be used at the sensor's edge to reduce the perimeter's dead volume to as low as ∼4 μm. Since 2009 four industrial partners of the 3D ATLAS R&D Collaboration started a joint effort aimed at one common design and compatible processing strategy for the production of 3D sensors for the LHC Upgrade and in particular for the ATLAS pixel Insertable B-Layer (IBL). In this project, aimed for installation in 2013, a new layer will be inserted as close as 3.4 cm from the proton beams inside the existing pixel layers of the ATLAS experiment. The detector proximity to the interaction point will therefore require new radiation hard technologies for both sensors and front end electronics. The latter, called FE-I4, is processed at IBM and is the biggest front end of this kind ever designed with a surface of ∼4 cm 2 . The performance of 3D devices from several wafers was evaluated before and after bump-bonding. Key design aspects, device fabrication plans and quality assurance tests during the 3D sensors prototyping phase are discussed in this paper.
113 citations
01 Jan 2012-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, a prototype particle tracking telescope was constructed using Timepix and Medipix ASIC hybrid pixel assemblies as the six sensing planes Each telescope plane consisted of one 14 cm2 assembly, providing a 256 ×256 array of 55μm square pixels The telescope achieved a pointing resolution of 24μm at the position of the device under test.
Abstract: A prototype particle tracking telescope was constructed using Timepix and Medipix ASIC hybrid pixel assemblies as the six sensing planes Each telescope plane consisted of one 14 cm2 assembly, providing a 256 ×256 array of 55μm square pixels The telescope achieved a pointing resolution of 24μm at the position of the device under test During a beam test in 2009 the telescope was used to evaluate in detail the performance of two Timepix hybrid pixel assemblies; a standard planar 300μm thick sensor, and 285μm thick double sided 3D sensor This paper describes a charge calibration study of the pixel devices, which allows the true charge to be extracted, and reports on measurements of the charge collection characteristics and Landau distributions The planar sensor achieved a best resolution of 40±01μm for angled tracks, and resolutions of between 44 and 11μm for perpendicular tracks, depending on the applied bias voltage The double sided 3D sensor, which has significantly less charge sharing, was found to have an optimal resolution of 90±01μm for angled tracks, and a resolution of 160±02μm for perpendicular tracks Based on these studies it is concluded that the Timepix ASIC shows an excellent performance when used as a device for charged particle tracking
73 citations
TL;DR: In this article, the authors presented a novel detector based on an ultra-thin 3D silicon sensor with a sensitive volume only 10 μm thick, which allows a high gamma-ray rejection, a key requirement in order to discriminate the signal coming from the neutrons in a mixed neutron-gamma ray environment.
Abstract: We present a novel neutron detector based on an ultra-thin 3D silicon sensor with a sensitive volume only 10 μm thick. This ultra-thin active volume allows a high gamma-ray rejection, a key requirement in order to discriminate the signal coming from the neutrons in a mixed neutron-gamma ray environment. The device upper-side is covered with a novel boron-based compound that detects neutrons by means of the 10B(n,α)7Li nuclear reaction. The performance of test devices has been investigated first with a gamma-ray source to evaluate the gamma-ray rejection factor, and then with an 241AmBe neutron source to assess the neutron-gamma ray discrimination properties.
34 citations
01 Oct 2012
TL;DR: For the ATLAS Phase II Upgrade, new silicon microstrip sensors located in the End-cap part of the Inner detector, will bring new issues related to their complex design and the petalet prototype was defined as a small End- cap prototype.
Abstract: For the ATLAS Phase II Upgrade, new silicon microstrip sensors located in the End-cap part of the Inner detector, will bring new issues related to their complex design In order to investigate the End-cap Upgrade specific problems, the petalet prototype was defined as a small End-cap prototype The software tools developed in this work for the automatic generation of microelectronic sensor layouts are very helpful for these developments and allow us to face these design difficulties New layout and technological solutions have been designed and implemented Sensors have been fabricated and first test results are presented
1 citations