Publications (8)0 Total impact
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Article: The Timepix Telescope for High Performance Particle Tracking
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ABSTRACT: The Timepix particle tracking telescope has been developed as part of the LHCb VELO Upgrade project, supported by the Medipix Collaboration and the AIDA framework. It is a primary piece of infrastructure for the VELO Upgrade project and is being used for the development of new sensors and front end technologies for several upcoming LHC trackers and vertexing systems. The telescope is designed around the dual capability of the Timepix ASICs to provide information about either the deposited charge or the timing information from tracks traversing the 14 x 14mm matrix of 55 x 55 um pixels. The rate of reconstructed tracks available is optimised by taking advantage of the shutter driven readout architecture of the Timepix chip, operated with existing readout systems. Results of tests conducted in the SPS North Area beam facility at CERN show that the telescope typically provides reconstructed track rates during the beam spills of between 3.5 and 7.5 kHz, depending on beam conditions. The tracks are time stamped with 1 ns resolution with an efficiency of above 98% and provide a pointing resolution at the centre of the telescope of 1.6 um . By dropping the time stamping requirement the rate can be increased to 15 kHz, at the expense of a small increase in background. The telescope infrastructure provides CO2 cooling and a flexible mechanical interface to the device under test, and has been used for a wide range of measurements during the 2011-2012 data taking campaigns.04/2013; -
Article: Charged Particle Tracking with the Timepix ASIC
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ABSTRACT: A prototype particle tracking telescope has been constructed using Timepix and Medipix ASIC hybrid pixel assemblies as the six sensing planes. Each telescope plane consisted of one 1.4 cm2 assembly, providing a 256x256 array of 55 micron square pixels. The telescope achieved a pointing resolution of 2.3 micron 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 300 micron thick sensor, and 285 micron thick double sided 3D sensor. This paper describes a detailed 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 4.0 micron for angled tracks, and resolutions of between 4.4 and 11 micron 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 9.0 micron for angled tracks, and a resolution of 16.0 micron 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.03/2011; -
Article: Laboratory and Testbeam Results on 3D Detectors
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ABSTRACT: This paper reports on recent test beam and laboratory results performed on 3D strip and pixel de-tectors. The devices were produced using a special double-sided 3D technology aimed to simplify the fabrication process, where the columnar electrodes etched into the silicon do not pass through the full substrate thickness. Double-sided 3D n-in-p strip detectors show good electrical and charge collection characteristics after heavy irradiation up to 2 × 10 16 n eq /cm 2 . An effect of charge multiplication is observed at high bias voltages, both in laboratory tests with radioactive source and in beam tests with pions. This multiplication effect is beneficial for the signal-to-noise ratio for moderate voltages and values > 40 can be achieved. The detection efficiency and charge sharing properties of the 3D structure have been investigated in Medipix2 pixel detectors with micro-focus synchrotron X-rays and pion beams and compared to that of the standard planar technology. There is a drop in the detection efficiency over the pixel of the 3D sensors due to the central electrodes, however the corner electrodes do not represent a significant degradation of the efficiency compared to that of the planar devices. The 3D sensors show a considerably reduced charge sharing compared to planar detectors that makes them very interesting for imaging applications.PoSVERTEX. 01/2010; -
Article: The LCFIVertex package: vertexing, flavour tagging and vertex charge reconstruction with an ILC vertex detector
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ABSTRACT: The precision measurements envisaged at the International Linear Collider (ILC) depend on excellent instrumentation and reconstruction software. The correct identification of heavy flavour jets, placing unprecedented requirements on the quality of the vertex detector, will be central for the ILC programme. This paper describes the LCFIVertex software, which provides tools for vertex finding and for identification of the flavour and charge of the leading hadron in heavy flavour jets. These tools are essential for the ongoing optimisation of the vertex detector design for linear colliders such as the ILC. The paper describes the algorithms implemented in the LCFIVertex package, as well as the scope of the code and its performance for a typical vertex detector design.08/2009; -
Article: Measurements of 3D Silicon Strip Sensors by Two Manufacturers
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ABSTRACT: The increase of the radiation dose at the luminosity upgrade of the LHC (sLHC) necessitates the development of novel tracking detectors. Among these, 3D silicon detectors constitute a promis-ing option. By etching columnar electrodes of both doping types into the sensor, the distance for depletion and charge collection is decoupled from the sensor thickness and can be considerably smaller than in standard planar sensors. Two of the main effects of radiation damage in silicon detectors (increasing depletion voltage and trapping) can be significantly reduced. Silicon strip detectors in 3D-DDTC (double-sided, double type column) design produced by FBK-IRST (Trento, Italy) and CNM-IMB (Barcelona, Spain) have been measured in a test beam at the CERN SPS. Important properties like spatially resolved charge collection and detection efficiency were investigated. -
Article: Beam test measurements with planar and 3D silicon strip detectors irradiated to sLHC fluences
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ABSTRACT: The planned luminosity upgrade of the CERN LHC to the super LHC (sLHC) requires investigation of new radia-tion hard tracking detectors. Compared to the LHC, tracking detectors must withstand a 5-10 times higher radiation fluence. Promising radiation hard options are planar silicon detectors with n-side readout and silicon detectors in 3D technology, where columnar electrodes are etched into the silicon substrate. This article presents beam test measurements performed with planar and 3D n-in-p silicon strip detectors. The detectors were irradi-ated to different fluences, where the maximum fluence was 3 × 10 15 1 MeV neutron equivalent particles per square centimetre (neq/cm 2) for the planar detectors and 2 × 10 15 neq/cm 2 for the 3D detectors. In addition to signal measurements, charge sharing and resolution of both detector technologies are com-pared. An increased signal from the irradiated 3D detectors at high bias voltages compared to the signal from the unirradiated detector indicates that charge multiplication effects occur in the 3D detectors. At a bias voltage of 260 V, the 3D detector irradiated to 2 × 10 15 neq/cm 2 yields a signal almost twice as high as the signal of the unirradiated detector. Only 30 % of the signal of an unirradiated detector could be measured with the planar detector irradiated to 3 × 10 15 neq/cm 2 at a bias voltage of 600 V, which was the highest bias voltage applied to this sensor. -
Article: Silicon microstrip detectors in 3D technology for the sLHC
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ABSTRACT: The projected luminosity upgrade of the large hadron collider (LHC), the sLHC, will constitute a challenging radiation environment for tracking detectors. Massive improvements in radiation hardness are required with respect to the LHC. In the layout for the new ATLAS tracker, silicon strip detectors (SSDs) with short strips cover the region from 28 to 60 cm distance to the beam. These SSDs will be exposed to fluences up to , hence radiation resistance is the major concern.It is advantageous to fuse the superior radiation hardness of the 3D design originally conceived for pixel-style applications with the benefits of the well-known planar technology for strip detectors. This is achieved by ganging rows of 3D columns together to form strips. Several prototype sLHC detector modules using 3D SSD with short strips, processed on p-type silicon, and LHC-speed front-end electronics from the present ATLAS semi-conductor tracker (SCT) were built. The modules were tested before and after irradiation to fluences of . The tests were performed with three systems: a highly focused IR-laser with spot size to make position-resolved scans of the charge collection efficiency (CCE), a Sr90β-source set-up to measure the signal levels for a minimum ionizing particles (MIPs), and a beam test with 180 GeV pions at CERN.This article gives a brief overview of the performance of these 3D modules, and draws conclusions about options for using 3D strip sensors as tracking detectors at the sLHC.Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. -
Article: 3D silicon strip detectors
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ABSTRACT: While the Large Hadron Collider (LHC) at CERN has started operation in autumn 2008, plans for a luminosity upgrade to the Super-LHC (sLHC) have already been developed for several years. This projected luminosity increase by an order of magnitude gives rise to a challenging radiation environment for tracking detectors at the LHC experiments. Significant improvements in radiation hardness are required with respect to the LHC. Using a strawman layout for the new tracker of the ATLAS experiment as an example, silicon strip detectors (SSDs) with short strips of 2–3 cm length are foreseen to cover the region from 28 to 60 cm distance to the beam. These SSD will be exposed to radiation levels up to , which makes radiation resistance a major concern for the upgraded ATLAS tracker. Several approaches to increasing the radiation hardness of silicon detectors exist.In this article, it is proposed to combine the radiation hard 3D-design originally conceived for pixel-style applications with the benefits of the established planar technology for strip detectors by using SSDs that have regularly spaced doped columns extending into the silicon bulk under the detector strips. The first 3D SSDs to become available for testing were made in the Single Type Column (STC) design, a technological simplification of the original 3D design. With such 3D SSDs, a small number of prototype sLHC detector modules with LHC-speed front-end electronics as used in the semiconductor tracking systems of present LHC experiments were built. Modules were tested before and after irradiation to fluences of . The tests were performed with three systems: a highly focused IR-laser with spot size to make position-resolved scans of the charge collection efficiency, an -source set-up to measure the signal levels for a minimum ionizing particle (MIP), and a beam test with 180 GeV pions at CERN. This article gives a brief overview of the results obtained with 3D-STC-modules.Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
Top co-authors
Institutions
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2010
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University of Glasgow
- School of Physics and Astronomy
Glasgow, SCT, United Kingdom
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2009
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University of Bristol
Bristol, ENG, United Kingdom
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