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.
The paper is based on the data of the 2009 DEPFET beam test at CERN SPS. The beam test used beams of pions and electrons with energies between 40 and 120
GeV, and the sensors tested were prototypes ...with thickness of
450
μ
m
and pixel pitch between 20 and
32
μ
m
. Intrinsic resolutions of the detectors are calculated by disentangling the contributions of measurement errors and multiple scattering in tracking residuals. Properties of the intrinsic resolution estimates and factors that influence them are discussed. For the DEPFET detectors in the beam test, the calculation yields intrinsic resolutions of
≈
1
μ
m
, with a typical accuracy of
0.1
μ
m
. Bias scan, angle scan, and energy scan are used as example studies to show that the intrinsic resolutions are a useful tool in studies of detector properties. With sufficiently precise telescopes, detailed resolution maps can be constructed and used to study and optimize detector performance.
SuperKEKB, the next generation B factory, has been constructed in Japan as an upgrade of KEKB. This brand new e+ e- collider is expected to deliver a very large data set for the Belle II experiment, ...which will be 50 times larger than the previous Belle sample. Both the triggered physics event rate and the background event rate will be increased by at least 10 times than the previous ones, and will create a challenging data taking environment for the Belle II detector. The software system of the Belle II experiment is designed to execute this ambitious plan. A full detector simulation library, which is a part of the Belle II software system, is created based on Geant4 and has been tested thoroughly. Recently the library has been upgraded with Geant4 version 10.1. The library is behaving as expected and it is utilized actively in producing Monte Carlo data sets for various studies. In this paper, we will explain the structure of the simulation library and the various interfaces to other packages including geometry and beam background simulation.
A new synthetic isothiocyanate (ITC) derivative, ethyl 4-isothiocyanatobutanoate (E-4IB), appeared to be an effective modulator of cellular proliferation and potent inducer of apoptosis. In ...cooperation with cisplatin, this compound exerted synergistic effects in human ovarian carcinoma A2780 cells. In the present study we investigated in more detail E4IB-sensitisation for cisplatin-induced apoptosis. Sequential administration of both cytostatic agents led to increased intracellular platinum accumulation, glutathione level depletion and mitochondrial membrane potential dissipation. These events were accompanied with poly (ADP-ribosyl) polymerase cleavage, stimulation of caspase-3 activity, upregulation of p53, FasL and Gadd45alpha, cyclin B1 downregulation and an increase in mitogen-activated protein kinases JNK, ERK and p38 phosphorylation as well as PI3K level alterations. The presented results might have implications for developing new strategies aimed at therapeutic benefit of natural or synthetic ITCs in cooperation with various anticancer drugs.
The most common mechanisms of the knee injuries are distortions and contusions. Fairly often they will result in hemarthrosis. The purpose of this study was to evaluate the findings in patients with ...acute traumatic hemarthrosis of the knee and based on these findings estimate the necessity of acute artroscopic examination with therapeutic procedure.
In the years 2007 and 2009 a total of 266 patients underwent acute arthroscopic examination in Department of Traumatology the Faculty Hospital Brno after the acute knee trauma. Patients with other intraarticular bone fractures were excluded.
The ruptures of the ACL were the most common findings (52 %), meniscal tear (27 %), dislocation of the patella (11 %) and chondral or subchondral fractures were (13 %). In 224 (84 %) cases was performed artroscopic therapeutic procedure and in only 43 (16 %) case was performed routine arthroscopic examination.
Based on our findings we believe that arthroscopic examination is necessary in patients with acute traumatic haemarthrosis of the knee and it is better methods like NMR examination because is provided to execute therapeutic procedure (Tab. 1, Fig. 2, Ref. 8). Full Text in PDF www.elis.sk.
Surface plasmon resonance (SPR) sensors use two types of surface plasmons: (i) propagating along a metal-dielectric interface and (ii) localized on metallic nano-objects. This article presents ...theoretical analysis of sensitivity of SPR sensors based on spectroscopy of localized surface plasmons on metallic nanoparticles. Analytical formulas inter-relating bulk and surface refractive index sensitivity with main design parameters are derived using the electrostatic approximation. The effect of particle diameter is accounted for by means of Mie theory. Figures of merit for SPR sensors using localized and propagating surface plasmons are calculated and compared. Although sensors based on spectroscopy of localized surface plasmons on gold spherical particles show promise for detection of processes occurring in the close proximity of the particle surface, their performance is still inferior to that of SPR sensors based on spectroscopy of propagating surface plasmons.
For the detection of secondary vertices of long lived particles containing bottom and charm quarks at the International Linear Collider (ILC), a DEPFET pixel detector is one of the technologically ...favored options. In a DEPFET sensor a MOSFET pixel detector is integrated on a sidewards depleted silicon bulk sensor, thus combining the advantages of a fully depleted silicon sensor with in-pixel amplification. DEPFET pixel matrices have been characterized in a high energy particle beam. Since the DEPFET is a very high precision device, given its large S/N (> 100) and small pixel size (36 × 22 ¿m 2 ), a DEPFET based pixel telescope consisting of 5 DEPFETs has been developed. The uncertainty on the predicted position for a device under test (DUT) positioned inside the telescope was found to be 1.4 ¿m with the existing device, due to the limited performance of two of the five DEPFET planes. A DEPFET telescope built of 5 modules equivalent to the best plane presented here, would have a track extrapolation error as low as 0.65 ¿m at the DUT plane.
Optimising the strip geometry for very fine pitch silicon strip sensors Dragicevic, M.; Bergauer, T.; Dolezal, Z. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2010, Letnik:
617, Številka:
1
Journal Article
Recenzirano
Future collider experiments will require tracking detectors with more precise silicon sensors for improved track reconstruction precision and possibly with the ability to provide input to the first ...level trigger. One way to enhance the tracking performance is the minimization of the readout pitch. We investigated the performance of such fine pitch strip sensors using multigeometry testsensors with a fixed readout pitch of
50
μ
m
and a varying number of intermediate strips and different strip widths. Results from a testbeam with
120
GeV
/
c
pions are presented, suggesting the best geometry for optimal spatial resolution. Furthermore we studied the possibility to derive the incidence angle of a particle from the cluster width, which could be used as a tracking trigger on transverse momentum.
A novel multi-channel fiber optic surface plasmon resonance (SPR) sensor is reported. The sensing structure consists of a single-mode optical fiber, covered with a thin gold layer, which supports a ...surface plasmon (SP), and a Bragg grating. The Bragg grating induces coupling between the forward-propagating fundamental core mode and the back-propagating SP-cladding mode. As the SP-cladding modes are highly sensitive to changes in the refractive index of the surrounding medium, the changes can be accurately measured by spectroscopy of these hybrid modes. Multichannel capability is achieved by employing a sequence of Bragg gratings of different periods and their reading via the wavelength division multiplexing. Theoretical analysis and optimization based on the coupled-mode theory (CMT) is carried out and performance characteristics of the sensor are determined.
Surface plasmon resonance (SPR) sensors are known to be able to detect very low surface concentrations of (bio)molecules on macroscopic areas. To explore the potential of SPR biosensors to achieve ...single-molecule detection, we have minimized the read-out area (to ~64 μm2) by employing a sensor system based on spectroscopy of surface plasmons generated on a diffractive structure via a microscope objective and light collection through a small aperture. This approach allows for decreasing the number of detected molecules by 3 orders of magnitude compared to state-of-the-art SPR sensors. A protein monolayer has been shown to produce a response of 5000 times the baseline noise, suggesting that as few as ~500 proteins could be detected by the sensor.
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