The upgrade of the ALICE TPC with GEMs and continuous readout

The upgrade of the ALICE TPC will allow the experiment to cope with the high interaction rates foreseen for the forthcoming Run 3 and Run 4 at the CERN LHC. In this article, we describe the design of new readout chambers and front-end electronics, which are driven by the goals of the experiment. Gas Electron Multiplier (GEM) detectors arranged in stacks containing four GEMs each, and continuous readout electronics based on the SAMPA chip, an ALICE development, are replacing the previous elements. The construction of these new elements, together with their associated quality control procedures, is explained in detail. Finally, the readout chamber and front-end electronics cards replacement, together with the commissioning of the detector prior to installation in the experimental cavern, are presented. After a nine-year period of R&D, construction, and assembly, the upgrade of the TPC was completed in 2020.publishedVersio

LBNL report of the vetting review of the GRETINA project

GRETINA is a gamma-ray detector array capable of reconstructing the energy and spatial positions of gamma-ray interactions within the germanium crystals. It will be used to study the structure and stability of nuclei under various conditions. The new capabilities provided by gamma-ray tracking will give large gains in sensitivity for a large number of experiments, particularly those aimed at nuclei far from beta stability. A proposal for GRETINA was submitted to DOE in June 2003. It presented the scientific case, the readiness of technical development, the design, the suggested management organizations, and a proposed cost and schedule. The GRETINA proposal received its CD0 approval in August 2003. The CD-1 review will be held on December 3 and 4, 2003, and will be handled by the DOE-N. This report presents the charge to the GRETINA vetting review committee, and the findings, comments and recommendations of this committee. The purpose of this project vetting review was to assure that the GRETINA project is on track to provide DOE and the nuclear physics community with the agreed upon deliverables within the agreed upon budget and schedule. The vetting review committee was asked to cover both technical and management aspects of the GRETINA Project. Reviewers offer expert knowledge in relevant areas and provide recommendations and findings to the project's management team. Upon successful completion, the Laboratory's Integrated Project Management Office (IPMO) will recommend signoff of the project to the Laboratory Directorate. The GRETINA vetting review committee was asked to consider all relevant aspects of the project's management, project execution plan (PEP), technical approach and status, cost estimate, resources, schedule and risk and, in doing so, to advise as to whether the GRETINA Project was likely to successfully provide the agreed upon deliverables within the agreed upon budget and schedule. The review committee was asked to identify any project areas that may be incomplete for the current phase in the project and any area of significant risk for the project reaching its objectives. The committee was also asked to review and evaluate the technical status of the project and advise on any concerns or significant technical risks

The upgrade of the ALICE TPC with GEMs and continuous readout

The upgrade of the ALICE TPC will allow the experiment to cope with the high interaction rates foreseen for the forthcoming Run 3 and Run 4 at the CERN LHC. In this article, we describe the design of new readout chambers and front-end electronics, which are driven by the goals of the experiment. Gas Electron Multiplier (GEM) detectors arranged in stacks containing four GEMs each, and continuous readout electronics based on the SAMPA chip, an ALICE development, are replacing the previous elements. The construction of these new elements, together with their associated quality control procedures, is explained in detail. Finally, the readout chamber and front-end electronics cards replacement, together with the commissioning of the detector prior to installation in the experimental cavern, are presented. After a nine-year period of R&D, construction, and assembly, the upgrade of the TPC was completed in 2020

The upgrade of the ALICE TPC with GEMs and continuous readout

The upgrade of the ALICE TPC will allow the experiment to cope with the high interaction rates foreseen for the forthcoming Run 3 and Run 4 at the CERN LHC. In this article, we describe the design of new readout chambers and front-end electronics, which are driven by the goals of the experiment. Gas Electron Multiplier (GEM) detectors arranged in stacks containing four GEMs each, and continuous readout electronics based on the SAMPA chip, an ALICE development, are replacing the previous elements. The construction of these new elements, together with their associated quality control procedures, is explained in detail. Finally, the readout chamber and front-end electronics cards replacement, together with the commissioning of the detector prior to installation in the experimental cavern, are presented. After a nine-year period of R&D, construction, and assembly, the upgrade of the TPC was completed in 2020

Observation of CP violation in the B0 meson system

We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 million B-anti-B pairs. We select events in which one neutral B meson is fully reconstructed in a final state containing charmonium and the flavor of the other neutral B meson is determined from its decay products. The amplitude of the CP-violating asymmetry, which in the Standard Model is proportional to sin2beta, is derived from the decay time distributions in such events. The result sin2beta = 0.59 +/- 0.14 (stat) +/- 0.05 (syst) establishes CP violation in the B^0 meson system. We also determine |lambda| = 0.93 +/- 0.09 {stat} +/- 0.03 {syst}, consistent with no direct CP violation.Comment: 8 pages, 2 figures, submitted to Physical Review Letter

Star detector overview

An introduction to the STAR detector and a brief overview of the physics goals of the experiment are presented. (C) 2002 Elsevier Science B.V. All rights reserved