High Resolution Hybrid Pixel Sensors for the e+e- TESLA Linear Collider Vertex Tracker

In order to fully exploit the physics potential of a future high energy e+e- linear collider, a Vertex Tracker, providing high resolution track reconstruction, is required. Hybrid Silicon pixel sensors are an attractive option, for the sensor technology, due to their read-out speed and radiation hardness, favoured in the high rate environment of the TESLA e+e- linear collider design but have been so far limited by the achievable single point space resolution. In this paper, a conceptual design of the TESLA Vertex Tracker, based on a novel layout of hybrid pixel sensors with interleaved cells to improve their spatial resolution, is presented.Comment: 12 pages, 5 figures, to appear in the Proceedings of the Vertex99 Workshop, Texel (The Netherlands), June 199

Characterisation of Hybrid Pixel Detectors with capacitive charge division

In order to fully exploit the physics potential of the future high energy e+ e- linear collider, a Vertex Tracker providing high resolution track reconstruction is required. Hybrid pixel sensors are an attractive technology due to their fast read-out capabilities and radiation hardness. A novel pixel detector layout with interleaved cells between the readout nodes has been developed to improve the single point resolution. The results of the characterisation of the first processed prototypes are reported.Comment: 5 pages, 2 figures, presented at LCWS2000, Linear Collider Workshop, October 24-28 2000, Fermi National Accelerator Laboratory, Batavia, Illinois, U.S.A. Proceedings to be published by the American Institute of Physic

Hybrid Pixel Detector Development for the Linear Collider Vertex Tracker

In order to fully exploit the physics potential of the future high energy e+e- linear collider, a Vertex Tracker able to provide particle track extrapolation with very high resolution is needed. Hybrid Si pixel sensors are an attractive technology due to their fast read-out capabilities and radiation hardness. A novel pixel detector layout with interleaved cells has been developed to improve the single point resolution. Results of the characterisation of the first processed prototypes by electrostatic measurements and charge collection studies are discussed.Comment: 5 pages, 1 figure, to appear in the Proceedings of the 9th Int. Workshop on Vertex Detectors, Lake Michigan MI (USA), September~200

A Pixel Vertex Tracker for the TESLA Detector

In order to fully exploit the physics potential of a e+e- linear collider, such as TESLA, a Vertex Tracker providing high resolution track reconstruction is required. Hybrid Silicon pixel sensors are an attractive sensor technology option due to their read-out speed and radiation hardness, favoured in the high rate TESLA environment, but have been so far limited by the achievable single point space resolution. A novel layout of pixel detectors with interleaved cells to improve their spatial resolution is introduced and the results of the characterisation of a first set of test structures are discussed. In this note, a conceptual design of the TESLA Vertex Tracker, based on hybrid pixel sensors is presentedComment: 20 pages, 11 figure

High resolution pixel detectors for e+e- linear colliders

The physics goals at the future e+e- linear collider require high performance vertexing and impact parameter resolution. Two possible technologies for the vertex detector of an experimental apparatus are outlined in the paper: an evolution of the Hybrid Pixel Sensors already used in high energy physics experiments and a new detector concept based on the monolithic CMOS sensors.Comment: 8 pages, to appear on the Proceedings of the International Workshop on Linear Colliders LCWS99, Sitges (Spain), April 28 - May 5, 199

Hybrid pixel detector development for the Linear collider Vertex Detector

In order to fully exploit the Physics potential of future e+ e- linear collider, a Vertex Detector providing high resolution track reconstruction is required. Hybrid Silicon pixel detectors are an attractive option for the sensor technology due to their read-out speed and radiation hardness but have been so far limited by the achievable single point resolution. A novel layout of hybrid pixel sensor with interleaved cells to improve the spatial resolution has been developed. The characterisation of the first processed prototypes is reported.Comment: 5 pages, 5 figures. Presented at the IEEE Nuclear Science Symposium and Medical Imaging Conference, October 15-20 2000, Lyon, Franc

Silicon Pad Detectors for the PHOBOS Experiment at RHIC

The PHOBOS experiment is well positioned to obtain crucial information about relativistic heavy ion collisions at RHIC, combining a multiplicity counter with a multi-particle spectrometer. The multiplicity arrays will measure the charged particle multiplicity over the full solid angle. The spectrometer will be able to identify particles at mid-rapidity. The experiment is constructed almost exclusively of silicon pad detectors. Detectors of nine different types are configured in the multiplicity and vertex detector (22,000 channels) and two multi-particle spectrometers (120,000 channels). The overall layout of the experiment, testing of the silicon sensors and the performance of the detectors during the engineering run at RHIC in 1999 are discussed.Comment: 7 pages, 7 figures, 1 table, Late

Collision geometry scaling of Au+Au pseudorapidity density from sqrt(s_NN) = 19.6 to 200 GeV

The centrality dependence of the midrapidity charged particle multiplicity in Au+Au collisions at sqrt(s_NN) = 19.6 and 200 GeV is presented. Within a simple model, the fraction of hard (scaling with number of binary collisions) to soft (scaling with number of participant pairs) interactions is consistent with a value of x = 0.13 +/- 0.01(stat) +/- 0.05(syst) at both energies. The experimental results at both energies, scaled by inelastic p(pbar)+p collision data, agree within systematic errors. The ratio of the data was found not to depend on centrality over the studied range and yields a simple linear scale factor of R_(200/19.6) = 2.03 +/- 0.02(stat) +/- 0.05(syst).Comment: 5 pages, 4 figures, submitted to PRC-R

Test of the photon detection system for the LHCb RICH Upgrade in a charged particle beam

The LHCb detector will be upgraded to make more efficient use of the available luminosity at the LHC in Run III and extend its potential for discovery. The Ring Imaging Cherenkov detectors are key components of the LHCb detector for particle identification. In this paper we describe the setup and the results of tests in a charged particle beam, carried out to assess prototypes of the upgraded opto-electronic chain from the Multi-Anode PMT photosensor to the readout and data acquisition system.Comment: 25 pages, 22 figure

Pseudorapidity and centrality dependence of the collective flow of charged particles in Au+Au collisions at sqrt{s_NN} = 130 GeV

This paper describes the measurement of collective flow for charged particles in Au+Au collisions at sqrt{s_NN}} = 130 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider (RHIC). An azimuthal anisotropy is observed in the charged particle hit distribution in the PHOBOS multiplicity detector. This anisotropy is presented over a wide range of pseudorapidity (eta) for the first time at this energy. The size of the anisotropy (v_{2}) is thought to probe the degree of equilibration achieved in these collisions. The result here,averaged over momenta and particle species, is observed to reach 7% for peripheral collisions at mid-rapidity, falling off with centrality and increasing |eta|. Data are presented as a function of centrality for |eta|<1.0 and as a function of eta, averaged over centrality, in the angular region -5.0<eta<5.3. These results call into question the common assumption of longitudinal boost invariance over a large region of rapidity in RHIC collisions.Comment: 5 pages, 4 figures, submitted to Physical Review Letter