The Belle II experiment at the SuperKEKB collider of KEK (Japan) will accumulate 50 ab−1 of e+e- collision data at an unprecedented instantaneous luminosity of 8⋅ 1035 cm−2s−1, about 40 times larger than its predecessor. The Belle II vertex detector plays a crucial role in the rich Belle II physics program, especially for time-dependent measurements. It consists of two layers of DEPFET-based pixels and four layers of double sided silicon strip sensors (SVD detector). We report here results of the standalone commissioning of the SVD and highlights from the first cosmic runs acquired in Belle II. We also report on reconstruction performances of a reduced-scale version of the SVD operated during the accelerator commissioning in 2018. © 2019

Prafulla Kumar Behera

Department Of Physics

Jim Libby

A. K. Basith

P. K. Resmi

Silicon

COMMISSIONING

PHYSICS PROGRAMS

REDUCED SCALE

SILICON STRIP SENSOR

SILICON VERTEX DETECTORS

Strip detectors

TIME DEPENDENT MEASUREMENTS

VERTEX DETECTORS

Cosmology

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Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

The Belle II Experiment at the High Energy Accelerator Research Organization (KEK) in Tsukuba, Japan, will explore the asymmetry between matter and antimatter and search for new physics beyond the standard model. 172 double-sided silicon strip detectors are arranged cylindrically in four layers around the collision point to be part of a system which measures the tracks of the collision products of electrons and positrons. A total of 1748 radiation-hard APV25 chips read out 128 silicon strips each and send the analog signals by time-division multiplexing out of the radiation zone to 48 Flash Analog Digital Converter Modules (FADC). Each of them applies processing to the data; for example, it uses a digital finite impulse response filter to compensate line signal distortions, and it extracts the peak timing and amplitude from a set of several data points for each hit, using a neural network. We present an overview of the SVD data readout system, along with front-end electronics, cabling, power supplies and data processing. © 2016 Elsevier B.V.

The Belle II SVD data readout system

The silicon vertex detector of the Belle II experiment, structured in a lantern shape, consists of four layers of ladders, fabricated from two to five silicon sensors. The APV25 readout ASIC chips are mounted on one side of the ladder to minimize the signal path for reducing the capacitive noise; signals from the sensor backside are transmitted to the chip by bent flexible fan-out circuits. The ladder is assembled using several dedicated jigs. Sensor motion on the jig is minimized by vacuum chucking. The gluing procedure provides such a rigid foundation that later leads to the desired wire bonding performance. The full ladder with electrically functional sensors is consistently completed with a fully developed assembly procedure, and its sensor offsets from the design values are found to be less than 200 μm. The potential functionality of the ladder is also demonstrated by the radioactive source test. © 2015 Elsevier B.V.

The silicon vertex detector of the Belle II experiment

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Journal	Data powered by TypesetNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Publisher	Data powered by TypesetElsevier B.V.
ISSN	01689002
Open Access	No