Tau lepton decays with up to two
π
0
s in the final state –
τ
+
→
π
+
ν
¯
τ
,
ρ
+
(
π
+
π
0
)
ν
¯
τ
, and
a
1
+
(
π
+
π
0
π
0
)
ν
¯
τ
– are used to study the performance of the barrel region of the ...silicon-tungsten electromagnetic calorimeter (Si-W ECAL) of the International Large Detector (ILD) at the future
e
+
e
-
International Linear Collider. Correct reconstruction of the tau decay mode is crucial for constraining the spin state of tau lepton and measuring the Higgs boson CP state in
H
→
τ
+
τ
-
decays. We find that about 95 % of
π
+
ν
¯
τ
, and 90 % of
ρ
+
ν
¯
τ
and
a
1
+
ν
¯
τ
decays produced by the
e
+
e
-
→
Z
0
∗
→
τ
+
τ
-
process at an
e
±
beam energy of 125 GeV are correctly reconstructed. In a smaller ILD detector, with the inner Si-W ECAL radius reduced by about 20 %, these efficiencies are reduced by at most 2 %. The
π
0
mass resolution remains below 10 %. Since failures in tau lepton reconstruction are mainly due to photons, an increase of the ILD magnetic field from 3.5 to 4 T does not bring any significant improvement.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The technological prototype of the CALICE highly granular silicon–tungsten electromagnetic calorimeter (SiW-ECAL) was tested in a beam at DESY in 2017. The setup comprised seven layers of silicon ...sensors. Each layer comprised four sensors, with each sensor containing an array of 256 5.5×5.5 mm2 silicon PIN diodes. The four sensors covered a total area of 18 × 18 cm and comprised a total of 1024 channels. The readout was split into a trigger line and a charge signal line. Key performance results for signal over noise for the two output lines are presented, together with a study of the uniformity of the detector response. Measurements of the response to electrons for the tungsten loaded version of the detector are also presented.
Silicon Calorimeters Brient, J.-C; Rusack, R; Sefkow, F
Annual review of nuclear and particle science,
10/2018, Letnik:
68, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We review the development of silicon-based calorimeters from the very first applications of small calorimeters used in collider experiments to the large-scale systems that are being designed today. ...We discuss silicon-based electromagnetic calorimeters for future
e
−
e
+
colliders and for the upgrade of the CMS experiment's endcap calorimeter to be used in the high-luminosity phase of the LHC. We present the intrinsic advantages of silicon as an active detector material and highlight the enabling technologies that have made calorimeters with very high channel densities feasible. We end by discussing the outlook for further extensions to the silicon calorimeter concept, such as calorimeters with fine-pitched pixel detectors.
The ILD Si-W ECAL is a sampling calorimeter with tungsten absorber and highly segmented silicon layers for the International Large Detector (ILD), one of the two detector concepts for the ...International Linear Collider. SKIROC2 is an ASIC for the ILD Si-W ECAL. To investigate the issues found in prototype detectors, we prepared dedicated ASIC evaluation boards with either BGA sockets or directly soldered SKIROC2. We report a performance study with the evaluation boards, including signal-to-noise ratio and TDC performance with comparing SKIROC2 and an updated version, SKIROC2A.
The staging of the ILC accelerator project to run at 250 GeV centre-of-mass energy, impacts directly the calorimeters design. The paper describes some of the consequences and draws the overall ...picture of the design in view of this impact.
A detailed investigation of hadronic interactions is performed using π−-mesons with energies in the range 2–10 GeV incident on a high granularity silicon–tungsten electromagnetic calorimeter. The ...data were recorded at FNAL in 2008. The region in which the π−-mesons interact with the detector material and the produced secondary particles are characterised using a novel track-finding algorithm that reconstructs tracks within hadronic showers in a calorimeter in the absence of a magnetic field. The principle of carrying out detector monitoring and calibration using secondary tracks is also demonstrated.
Abstract A neural network for software compensation was developed for the highly granular CALICE Analogue Hadronic Calorimeter (AHCAL). The neural network uses spatial and temporal event information ...from the AHCAL and energy information, which is expected to improve sensitivity to shower development and the neutron fraction of the hadron shower. The neural network method produced a depth-dependent energy weighting and a time-dependent threshold for enhancing energy deposits consistent with the timescale of evaporation neutrons. Additionally, it was observed to learn an energy-weighting indicative of longitudinal leakage correction. In addition, the method produced a linear detector response and outperformed a published control method regarding resolution for every particle energy studied.
Background
The treatment of papillary thyroid carcinomas larger than 1 cm usually consists of total thyroidectomy and central lymph node dissection (LND). In patients with the follicular variant of ...papillary thyroid carcinoma (FVPTC), preoperative cytology and intraoperative frozen‐section analysis cannot always establish the diagnosis. The aim of this study was to evaluate predictive factors for lymph node metastasis in patients with FVPTC and to identify patients who might benefit from LND.
Methods
The study included patients with FVPTC treated by total thyroidectomy and LND between 2000 and 2010 in four departments. When fewer than six non‐involved lymph nodes were removed, the patient was excluded from the analysis.
Results
Some 199 patients were included. The median tumour size was 17 (range 1–85) mm, and tumours were classified as T1a in 28 patients, T1b in 40, T2 in 53, and T3 in 78. Eighty‐one patients (40·7 per cent) had lymph node metastasis (51 classified as N1a and 30 as N1b). Four risk factors were predictive of lymph node metastasis in the multivariable analysis: multifocality (odds ratio (OR) 2·36, 95 per cent confidence interval 1·15 to 4·86), angiolymphatic invasion (OR 3·67, 1·01 to 13·36), absence of tumour capsule (OR 3·00, 1·47 to 6·14) and tumour involvement of perithyroid tissue (OR 3·89, 1·85 to 8·18). The rate of lymph node metastasis varied between 14 and 94 per cent depending on the presence of risk factors.
Conclusion
The rate of lymph node metastasis in patients with FVPTC varies widely according to the presence or absence of predictive risk factors.
Lymph node dissection could be omitted in many patients
The CALICE Semi-Digital Hadronic Calorimeter (SDHCAL) prototype, built in 2011, was exposed to beams of hadrons, electrons and muons in two short periods in 2012 on two different beam lines of the ...CERN SPS. The prototype with its 48 active layers, made of Glass Resistive Plate Chambers and their embedded readout electronics, was run in triggerless and power-pulsing mode. The performance of the SDHCAL during the test beam was found to be very satisfactory with an efficiency exceeding 90% for almost all of the 48 active layers. A linear response (within + or - 5%) and a good energy resolution are obtained for a large range of hadronic energies (5-80 GeV) by applying appropriate calibration coefficients to the collected data for both the Digital (Binary) and the Semi-Digital (Multi-threshold) modes of the SDHCAL prototype. The Semi-Digital mode shows better performance at energies exceeding 30 GeV.
SiW ECAL for future e + e − collider Balagura, V.; Bilokin, S.; Bonis, J. ...
Journal of instrumentation,
07/2017, Letnik:
12, Številka:
7
Journal Article
Recenzirano
Calorimeters with silicon detectors have many unique features and are proposed for several world-leading experiments. We discuss the tests of the first three 18×18 cm2 layers segmented into 1024 ...pixels of the technological prototype of the silicon-tungsten electromagnetic calorimeter for a future e+e− collider. The tests have beem performed in November 2015 at CERN SPS beam line.
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