Building on the success of the current KEKB Flavour Factory and the Belle experiment, which helped to firmly establish the CKM picture of quark mixing and CP violation in the Standard Model, a ...luminosity upgrade of the asymmetric e
+e
− machine is planned. This new Super Flavour Factory, SuperKEKB, will deliver a luminosity of 8×10
35
cm
−2
s
−1, a factor 40 of increase over the present luminosity world record. It is foreseen to begin its operation in 2013. With these increased statistics, a new silicon vertex detector is needed in order to obtain precise decay vertex resolution measurements; these new precise measurements in the flavour sector can probe new physics well beyond the scales accessible to direct observations.
The DMAPS upgrade of the Belle II vertex detector Babeluk, M.; Barbero, M.; Baudot, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2024, Letnik:
1064
Journal Article
Recenzirano
The Belle II experiment at KEK in Japan considers an upgrade for the vertex detector system in line with the accelerator upgrade for higher luminosity at long shutdown 2 planned for 2028.
One ...proposal for the upgrade of the vertex detector called VTX aims to improve background robustness and reduce occupancy using small and fast pixels. VTX accommodates the OBELIX depleted monolithic active CMOS pixel sensor (DMAPS) on all five proposed layers. OBELIX is specifically developed for the VTX application and based on the TJ-Monopix2 chip initially developed to meet the requirements of the outer layers of the ATLAS inner tracker (ITk).
This paper will review recent tests of the TJ-Monopix2 chip as well as various design aspects of the OBELIX-1 chip currently under development.
An upgrade of the successful asymmetric e
+e
− collider in KEK (Tsukuba, Japan) is foreseen by the fall of 2013. This new Super Flavor Factory will deliver an increased instantaneous luminosity of up ...to
L
=
8
×
10
35
cm
−
2
s
−
1
, 40 times larger than the current KEKB machine. To exploit these new conditions and provide high precision measurements of the decay vertex of the B meson systems, a new silicon vertex detector will be operated in Belle. This new detector will consist of two layers of DEPFET Active Pixel Sensors as close as possible to the interaction point.
DEPFET is a field effect transistor, with an additional deep implant underneath the channel's gate, integrated on a completely depleted bulk. This technology offers detection and an in-pixel amplification stage, while keeping low the power consumption. Under these conditions, thin sensors with small pixel size and low intrinsic noise are possible.
In this article, an overview of the full system will be described, including the sensor, the front-end electronics and both the mechanical and thermal proposed solutions as well as the expected performance.
An upgrade of the existing Flavour Factory KEKB (Tsukuba, Japan) is under construction, and is foreseen for commissioning by the end of 2014. This new e super(+)e super(-) machine ("SuperKEKB") will ...deliver an instantaneous luminosity of 8.10 super(35) cm super(-2)s super(-1), which is 40 times higher than the world record set by KEKB. In order to be able to fully exploit the increased number of events and provide high precision measurements of the decay vertex of the B meson systems in such a harsh environment, the Belle detector will be upgraded ("Belle II") and a new silicon vertex detector, based on the DEPFET technology, will be designed and constructed. The new pixel detector, close to the interaction point, will consist of two layers of DEPFET active pixel sensors. This technology combines the detection together with the in-pixel amplification by the integration, on every pixel, of a field effect transistor into a fully depleted silicon bulk. In Belle II, DEPFET sensors thinned down to 75 mu m with low power consumption and low intrinsic noise will be used.
Chronic wounds represent one of the complications that might occur from the disruption of wound healing process. Recently, there has been a rise in interest in employing nanotechnology to develop ...novel strategies for accelerating wound healing. The aim of the present study was to use a green synthesis method to obtain AgNPs/NaLS systems useful for wounds management and perform an in-depth investigation of their behavior during and post-synthesis as well as of their biological properties. The colloids obtained from silver nanoparticles (AgNPs) and commercial sodium lignosulfonate (NaLS) in a single-pot aqueous procedure have been fully characterized by UV–Vis, FT-IR, DLS, TEM, XRD, and XPS to evaluate the synthesis efficiency and to provide new insights in the process of AgNPs formation and NaLS behavior in aqueous solutions. The effects of various concentrations of NaLS (0–16 mg/mL) and AgNO3 (0–20 mM) and of two different temperatures on AgNPs formation have been analyzed. Although the room temperature is feasible for AgNPs synthesis, the short mixing at 70 °C significantly increases the speed of nanoparticle formation and storage stability. In all experimental conditions AgNPs of 20–40 nm in size have been obtained. The antimicrobial activity assessed quantitatively on clinical and reference bacterial strains, both in suspension and biofilm growth state, revealed a broad antimicrobial spectrum, the most intensive inhibitory effect being noticed against Pseudomonas aeruginosa and Escherichia coli strains. The AgNP/NaLS enhanced the NO extracellular release, potentially contributing to the microbicidal and anti-adherence activity by protein oxidation. Both AgNP/NaLS and NaLS were non-hemolytic (hemolytic index<5%, 2.26 ± 0.13% hemolysis) and biocompatible (102.17 ± 3.43 % HaCaT cells viability). The presence of AgNPs increased the antioxidative activity and induced a significant cytotoxicity on non-melanoma skin cancer cells (62.86 ± 8.27% Cal-27 cells viability). Taken together, all these features suggest the multivalent potential of these colloids for the development of novel strategies for wound management, acting by preventing infection-associated complications and supporting the tissue regeneration.
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The new Japanese Super Flavor Factory Belle II is designed with high precision in mind, making a good vertex resolution a necessity. In order to achieve the required resolution in the vertex ...reconstruction, besides highly segmented pixel detectors, the material budget has to be kept at very low levels, since more material results in multiple scattering and degrades the resolution. As a consequence, there is a direct impact on the cooling system, that has to be carefully designed, not allowing active cooling pipes inside the acceptance region. In this asymmetric e+e− experiment the angular acceptance ranges from 17° to 150°, leaving room for support structures outside this range. The Belle II vertex detector includes DEPFET technology in its vertex detector the front end electronics (FEE) of which, placed outside the acceptance, can be cooled by 2-phase CO2 through massive support structures while the sensitive area relies on forced convection with cold nitrogen gas.
Abstract The SuperKEKB collider will undergo a major upgrade to reach the target luminosity of 6 × 10 35 cm -2 s -1 during the long shutdown (LS2) foreseen to start around year 2027. We are ...developing a new vertex detector (VTX) to replace the current one (VXD). This new pixel silicon tracker aims to be both more robust against the higher level of machine background and more performant in terms of precision on the decay vertices and standalone track finding efficiency. The baseline layout consists of two layers composing the inner part (iVTX) and three outer layers (oVTX), all arranged in a barrel-shaped geometry, with minimal material budget. All layers will be equipped with dedicated depleted monolithic active CMOS pixel sensors (DMAPS) named OBELIX, designed in the TowerJazz 180 nm technology. This paper will review all the aspects of the project: the detector specifications and the baseline design, the expected improved performance, the OBELIX features and its design status, including the tests of the forerunner chip TJ-Monopix2, and the fabrication and tests for the iVTX and oVTX ladder prototypes.
Abstract
The Belle II experiment at KEK in Japan considers upgrading its vertex detector system to
address the challenges posed by high background levels caused by the increased luminosity of the
...SuperKEKB collider. One proposal for upgrading the vertex detector aims to install a 5-layer all
monolithic pixel vertex detector based on fully depleted CMOS sensors in 2027. The new system will
use the OBELIX MAPS chips to improve background robustness and reduce occupancy levels through
small and fast pixels. This causes better track finding, especially for low transverse momenta
tracks. This text will focus on the predecessor of the OBELIX sensor, the TJ-Monopix2, presenting
laboratory and test beam results on pixel response, efficiency, and spatial resolution.
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