The Belle II SVD detector

The Silicon Vertex Detector (SVD) is one of the main detectors in the Belle II experiment at KEK, Japan. In combination with a pixel detector, the SVD determines precise decay vertex and low-momentum track reconstruction. The SVD ladders are being developed at several institutes. For the development of the tracking algorithm as well as the performance estimation of the ladders, beam tests for the ladders were performed. We report an overview of the SVD development, its performance measured in the beam test, and the prospect of its assembly and commissioning until installation

Performance studies of the Belle II Silicon Vertex Detector with data taken at the DESY test beam in April 2016

Belle II is a multipurpose detector currently under construction which will be operated at the next generation B-factory SuberKEKB in Japan. Its main devices for the vertex reconstruction are the Silicon Vertex Detector (SVD) and the Pixel Detector (PXD). In April 2016 a sector of the Belle II SVD and PXD have been tested in a beam of high energetic electrons at the test beam facility at DESY Hamburg (Germany). We report here the results for the hit efficiency estimation and the measurement of the resolution for the Belle II silicon vertex etector. We find that the hit efficiencies are on average above 99.5% and that the measured resolution is within the expectations

Performance studies of the Belle II Silicon Vertex Detector with data taken at the DESY test beam in April 2016

Belle II is a multipurpose detector currently under construction which will be operated at the next generation B-factory SuberKEKB in Japan. Its main devices for the vertex reconstruction are the Silicon Vertex Detector (SVD) and the Pixel Detector (PXD). In April 2016 a sector of the Belle II SVD and PXD have been tested in a beam of high energetic electrons at the test beam facility at DESY Hamburg (Germany). We report here the results for the hit efficiency estimation and the measurement of the resolution for the Belle II silicon vertex etector. We find that the hit efficiencies are on average above 99.5% and that the measured resolution is within the expectations

Belle-II VXD radiation monitoring and beam abort with sCVD diamond sensors

The Belle-II VerteX Detector (VXD) has been designed to improve the performances with respect to Belle and to cope with an unprecedented luminosity of View the MathML source8 71035cm 122s 121 achievable by the SuperKEKB. Special care is needed to monitor both the radiation dose accumulated throughout the life of the experiment and the instantaneous radiation rate, in order to be able to promptly react to sudden spikes for the purpose of protecting the detectors. A radiation monitoring and beam abort system based on single-crystal diamond sensors is now under an active development for the VXD. The sensors will be placed in several key positions in the vicinity of the interaction region. The severe space limitations require a challenging remote readout of the sensors

Performance and running experience of the Belle II silicon vertex detector

The Belle II silicon vertex detector is one of the vertex detectors in the Belle II experiment. The detector reads out the signals from the double-sided silicon strip sensors with the APV25 front-end readout ASIC, adopting the chip-on-sensor concept to minimize the strip noise. The detector has been operated in the experiment since the spring of 2019. Analyzing the acquired data during the beam collisions, the excellent performance of the detector is confirmed. Also, the radiation dose and 1-MeV equivalent neutron fluence of the detector are estimated using the measured dose rates of the diamond sensors installed on the beam pipe and are compared with the measured radiation effects in the strip noise, leakage current, and depletion voltage. This paper briefly introduces the main features of the silicon vertex detector, and then reports on the measured performance and radiation effects of the first two years of running experience of the detector

New Results from the Silicon Vertex Detector of the Belle II Experiment

The Silicon Vertex Detector (SVD) consists of four layers of double-sided silicon strip sensors. The SVD is one of the two vertex subdetectors within Belle II. Since the start of data taking in 2019 at the Super-KEKB collider (KEK, Japan), which has the highest peak-luminosity ever recorded, the SVD is operated reliably and with high efficiency, despite exposure to harsh beam background. Measurements using data show that the SVD has both high signal-to-noise ratio and hit efficiency, as well precise spatial resolution. Further these properties are stable over time. Recently the simulation has been tuned, using data, to improve the agrement between data and MC for cluster properties. The good hit-time resolution can be exploited to further improve the robustness against the higher levels of background expected as the instantaneous luminosity increases in the next years of running. First effects of radiation damage on strip noise, sensor currents and depletion voltage have been measured, although they do not have any detrimental effect on the performance of the detector

Belle II silicon vertex detector (SVD)

The Belle II experiment at the SuperKEKB collider in Japan will operate at an unprecedented luminosity of 8 71035 cm 122s 121, about 40 times larger than its predecessor, Belle. Its vertex detector is composed of a two-layer DEPFET pixel detector (PXD) and a four layer double-sided silicon microstrip detector (SVD). To achieve a precise decay-vertex position determination and excellent low-momentum tracking under a harsh background condition and high trigger rate of 10 kHz, the SVD employs several innovative techniques. In order to minimize the parasitic capacitance in the signal path, 1748 APV25 ASIC chips, which read out signal from 224 k strip channels, are directly mounted on the modules with the novel Origami concept. The analog signal from APV25 are digitized by a flash ADC system, and sent to the central DAQ as well as to online tracking system based on SVD hits to provide region of interests to the PXD for reducing the latter\u2019s data size to achieve the required bandwidth and data storage space. Furthermore, the state-of-the-art dual phase CO2 cooling solution has been chosen for a combined thermal management of the PXD and SVD system. In this proceedings, we present key design principles, module construction and integration status of the Belle II SVD

Belle II Vertex Detector Performance

The Belle II experiment at the SuperKEKB accelerator (KEK, Tsukuba, Japan) collected its first e+e− collision data in the spring 2019. The aim of accumulating a 50 times larger data sample than Belle at KEKB, a first generation B-Factory, presents substantial challenges to both the collider and the detector, requiring not only state-of-the-art hardware, but also modern software algorithms for tracking and alignment. The broad physics program requires excellent performance of the vertex detector, which is composed of two layers of DEPFET pixels and four layers of double sided-strip sensors. In this contribution, an overview of the vertex detector of Belle II and our methods to ensure its optimal performance, are described, and the first results and experiences from the first physics run are presented