The Belle II experiment searches for beyond-the-standard-model physics using the Belle II detector and SuperKEKB collider. The silicon vertex detector (SVD) is crucial for particle tracking. After ...the 1.5-year shutdown from June 2022, Run 2 began in January 2024; Run 2 operation shows stable noise levels, high signal-to-noise ratios, and hit efficiency over 99%. To manage higher beam background from increased luminosity, new techniques such as hit-time selection and cluster grouping are being developed. These methods increase the acceptable level of occupancy by distinguishing hits from triggered collisions and other sources.
The future Belle II experiment will employ a computer-farm based data reduction system for the readout of its innermost detector, a DEPFET-technology based silicon detector with pixel readout. A ...large fraction of the background hits can be rejected by defining a set of regions of interest (ROIs) on the pixel detector sensors (PXD) and then recording just the data from the pixels inside the ROI. The ROIs are defined on an event by event basis by extrapolating back onto the PXD the charged tracks detected in the outer trackers (a four-layer double-sided silicon strip detector surrounded by a wire chamber). The tracks are reconstructed in real time on the High Level Trigger (HLT). The pixel detector is then read out based on the ROI information. A demonstrator of this architecture was under beam test earlier this year in DESY (Hamburg, Germany). The demonstrator was operated in an electron beam whose momentum was in the 2-6 GeV/c range with a typical trigger rate of a few kilohertz in a magnetic field of strength up to 1 T. The demonstrator consists of one pixel sensor and four silicon strip sensors arranged in a five-layer configuration mimicking the Belle II vertex detector. The detector readout was a scaled down version of the full Belle II DAQ + HLT chain. The demonstrator was used to detect the particles, reconstruct in real time the trajectories, identify the ROIs on the PXD plane and record the PXD data within. We describe the requirements and the architecture of the final system together with the results obtained with the demonstrator.
Thin pixel development for the SuperB silicon vertex tracker Rizzo, G.; Avanzini, C.; Batignani, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2011, Volume:
650, Issue:
1
Journal Article
Peer reviewed
The high luminosity SuperB asymmetric
e
+
e
−
collider, to be built near the INFN National Frascati Laboratory in Italy, has been designed to deliver a luminosity greater than 10
36
cm
−2
s
−1 with ...moderate beam currents and a reduced center of mass boost with respect to earlier B-Factories. An improved vertex resolution is required for precise time-dependent measurements and the SuperB Silicon Vertex Tracker will be equipped with an innermost layer of small radius (about 1.5
cm), resolution of
10
–
15
μ
m
in both coordinates, low material budget (
<
1
%
X0), and able to withstand a background rate of several tens of MHz/cm
2. The ambitious goal of designing a thin pixel device with these stringent requirements is being pursued with specific R&D programs on different technologies: hybrid pixels, CMOS MAPS and pixel sensors developed with vertical integration technology. The latest results on the various pixel options for the SuperB SVT will be presented.
A battery-powered, wireless Radon sensor has been designed and realized using a BJT, fabricated on a high-resistivity-silicon substrate, as a radiation detector. Radon daughters are electrostatically ...collected on the detector surface. Thanks to the BJT internal amplification, real-time α particle detection is possible using simple readout electronics, which records the particle arrival time and charge. Functional tests at known Radon concentrations, demonstrated a sensitivity up to 4.9cph/(100Bq/m3) and a count rate of 0.05cph at nominally-zero Radon concentration.
Physics and high background conditions set very challenging requirements on readout speed, material budget and resolution for the innermost layer of the SuperB Silicon Vertex Tracker operated at the ...full luminosity. Monolithic Active Pixel Sensors (MAPS) are very appealing in this application since the thin sensitive region allows grinding the substrate to tens of microns. Deep N-Well MAPS, developed in the ST 130nm CMOS technology, achieved in-pixel sparsification and fast time stamping. Further improvements are being explored with an intense R&D program, including both vertical integration and 2D MAPS with the INMAPS quadruple well. We present the results of the characterization with IR laser, radioactive sources and beam of several chips produced with the 3D (Chartered/Tezzaron) process. We have also studied prototypes exploiting the features of the quadruple well and the high resistivity epitaxial layer of the INMAPS 180nm process. Promising results from an irradiation campaign with neutrons on small matrices and other test-structures, as well as the response of the sensors to high energy charged tracks are presented.
The latest advances in the design and characterization of several pixel sensors developed to satisfy the very demanding requirements of the innermost layer of the SuperB Silicon Vertex Tracker will ...be presented in this paper. The SuperB machine is an electron positron collider operating at the ϒ(4S) peak to be built in the very near future by the Cabibbo Lab consortium. A pixel detector based on extremely thin, radiation hard devices able to cope with rate in the tens of MHz/cm2 range will be the optimal solution for the upgrade of the inner layer of the SuperB tracking system. At present several options with different levels of maturity are being investigated to understand advantages and potential issues of the different technologies: thin hybrid pixels, Deep N-Well CMOS MAPS, INMAPS CMOS MAPS featuring a quadruple well and high resistivity substrates and CMOS MAPS realized with Vertical Integration technology. The newest results from beam test, the outcomes of the radiation damage studies and the laboratory characterization of the latest prototypes will be reported.
The superB silicon vertex tracker Rizzo, G.; Avanzini, C.; Batignani, G. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Volume:
617, Issue:
1
Journal Article
Peer reviewed
Open access
The SuperB asymmetric
e
+
–
e
-
collider has been designed to deliver a luminosity greater than
10
36
cm
-
2
s
-
1
with moderate beam currents. Comparing to current B-Factories, the reduced center of ...mass boost of the SuperB machine requires improved vertex resolution to allow precision measurements sensitive to New Physics. We present the conceptual design of the silicon vertex tracker (SVT) for the SuperB detector with the present status of the R&D on the different options under study for its innermost Layer0.
The SuperB experiment needs large samples of MonteCarlo simulated events in order to finalize the detector design and to estimate the data analysis performances. The requirements are beyond the ...capabilities of a single computing farm, so a distributed production model capable of exploiting the existing HEP worldwide distributed computing infrastructure is needed. In this paper we describe the set of tools that have been developed to manage the production of the required simulated events. The production of events follows three main phases: distribution of input data files to the remote site Storage Elements (SE); job submission, via SuperB GANGA interface, to all available remote sites; output files transfer to CNAF repository. The job workflow includes procedures for consistency checking, monitoring, data handling and bookkeeping. A replication mechanism allows storing the job output on the local site SE. Results from 2010 official productions are reported.
PDF
