D. Esperante

Charged particle tracking with the Timepix ASIC

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 1.4 cm2 assembly, providing a 256 ×256 array of 55μm square pixels. The telescope achieved a pointing resolution of 2.4μm 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 4.0±0.1μm for angled tracks, and resolutions of between 4.4 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 9.0±0.1μm for angled tracks, and a resolution of 16.0±0.2μm 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.

The LHCb VELO upgrade

Abstract The LHCb experiment plans to have a fully upgraded detector and data acquisition system in order to take data with instantaneous luminosities up to 5 times greater than currently. For this reason the first tracking and vertexing detector, the VELO, will be completely redesigned to be able to cope with the much larger occupancies and data acquisition rates. Two main design alternatives, micro-strips or pixel detectors, are under consideration to build the upgraded detector. This paper describes the options presently under consideration, as well as a few highlights of the main aspects of the current R&D. Preliminary results using a pixel telescope are also presented.

The timepix telescope for high performance particle tracking

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 14×14 mm matrix of View the MathML source pixels. The rate of reconstructed tracks available is optimised by taking advantage of the shutter driver 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 View the MathML source. By dropping the time stamping requirement the rate can be increased to View the MathML source, 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.

Production of the LHCb Silicon Tracker Readout Electronics

A. Vollhardt, A. Bay, B. Carron, P. Fauland, R. Frei, S. Jimenez-Otero, A. Perrin, M.T. Tran, J. van Hunen, K. Vervink, M. Agari, C. Bauer, J. Blouw, W. Hofmann, K.T. Knopfle, S. Lochner, M. Schmelling, B. Schwingenheuer, N. Smale, B. Adeva, D. Esperante, C. Lois, P. Vazquez, R.P. Bernhard, R. Bernet, J. Gassner, S. Kostner, F. Lehner, M. Needham, O. Steinkamp, U. Straumann, D. Volyanskyy, H. Voss, A. Wenger

Preliminary Results using Timepix as a Particle Tracking Detector

A series of tests in CERN’s North Area beam facility have been used to demonstrate the suitability of the Timepix chip, combined with a silicon sensor, as a particle tracking device. Specifically of interest is the potential of a successor to the current chip to be used in the context of an LHCb VELO upgrade. The 55mm square pixels, large active fraction and analogue information make the chip very attractive for forward, high precision tracking systems such as the VELO. In this contribution preliminary results are presented showing the resolution achieved by a Timepix assembly in a 120GeV p beam, over a wide range of incident angles. At the optimum angle the detector was able to provide an unbiased track residual of 5.5mm. The telescope constructed for these measurements contributed a track extrapolation error of 2.5mm. The plans for a future development of this telescope, also based on Timepix assemblies are discussed, with proposals for upgrading its spatial and timing resolution.

LHCb Silicon Tracker Performance Studies

LHCb is one of the experiments for the Large Hadron Collider at CERN and is dedicated to B-physics and CP-violation measurements. To exploit its physics potential good tracking performance with high efficiency in a high particle density environment close to the beam pipe is required. Silicon strip detectors with large read-out pitch and long strips will be used for the LHCb Inner Tracker behind the magnet and the Trigger Tracker station in front of the magnet. We report here about the design of the Silicon Tracker, test beam results and the electrical tests foreseen during production