The experience gained in the operation of the present High Voltage system of the Tile calorimeter in the ATLAS detector and the new HL-LHC constraints, in particular the increase of the radiation, ...lead to the proposal of changing the currently embedded regulation system to be a remote system in the counting room, by adding easily new functionalities. The system described in this note is using the same regulation scheme as the current one and distributes the individual High Voltage settings with 100 m long multi-conductor cables. The tests show that it reaches the same good performance in terms of regulation stability and noise, while allowing a permanent access to the electronics.
The present article introduces a novel ASIC architecture, designed in the context of the ATLAS Tile Calorimeter upgrade program for the High-Luminosity phase of the Large Hadron Collider at CERN . ...The architecture is based on radiation-tolerant 130 nm Complementary Metal-Oxide-Semiconductor technology, embedding both analog and digital processing of detector signals. A detailed description of the ASIC is given in terms of motivation, design characteristics, simulated and measured performance. Experimental studies, based on 24 prototype chips under real particle beam conditions are also presented in order to demonstrate the potential of the architecture as a reliable front-end readout electronic solution.
This article documents the characteristics of the high voltage (HV) system of the hadronic calorimeter TileCal of the ATLAS experiment. Such a system is suitable to supply reliable power distribution ...into particles physics detectors using a large number of PhotoMultiplier Tubes (PMTs). Measurements performed during the 2015 and 2016 data taking periods of the ATLAS detector show that its performance, in terms of stability and noise, fits the specifications. In particular, almost all the PMTs show a voltage instability smaller than 0.5 V corresponding to a gain stability better than 0.5%. A small amount of channels was found not working correctly. To diagnose the origin of such defects, the results of the HV measurements were compared to those obtained using a Laser system. The analysis shows that less than 0.2% of the about 10 thousand HV channels were malfunctioning.
Polynomial Chaos Expansion (PCE) is a powerful and flexible metamodeling technique, but suffers from the fact that the number of required training samples grows exponentially with the dimensionality ...of the problem. Recently, proper generalized decomposition (PGD) has become a popular way to address this challenge since its complexity grows linearly with the dimension of the problem. In this work, we present a new technique called PGD–PCE, which combines the advantages of both methods. The algorithm is based on separate representations and constructed by orthonormal polynomial functions. We test the proposed approach on simple toy problems and engineering finite element problems. The results show that PGD–PCE performs well in terms of accuracy and computational efficiency when dealing with large problems.
•We propagate uncertainties in mechanical problems.•We develop a simple to implement and non-intrusive method.•We show that accuracy is preserved while cost drastically decrease.•We illustrate the capabilities of the approach on various numerical tests.
The ATLAS Collaboration has started a vast program of upgrades in the context of high-luminosity LHC (HL-LHC) foreseen in 2024. The current readout electronics of every sub-detector, including the ...Tile Calorimeter, must be upgraded to comply with the extreme HL-LHC operating conditions. The ASIC described in this document, named Front-end ATlAs tiLe Integrated Circuit (FATALIC), has been developed to fulfill these requirements. FATALIC is based on a 130 nm CMOS technology and performs the complete signal processing (amplification, shaping and digitization) over a large dynamic range. A dedicated channel for low current is also designed to perform the detector calibration with a radioactive cesium source. The design and performances of FATALIC are described including test beam data analysis.
•Complete signal processing inside a single chip over ∼104 dynamic range.•Reading current directly without current–voltage conversion.•Performances evaluated in test bench, test beam and in simulation for high pile-up.
A PMT-Block test bench Adragna, P.; Antonaki, A.; Boudagov, I. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2006, Letnik:
564, Številka:
1
Journal Article
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The front-end electronics of the ATLAS hadronic calorimeter (Tile Cal) is housed in a unit, called
PMT-Block. The PMT-Block is a compact instrument comprising a light mixer, a PMT together with its ...divider and a
3-in-1 card, which provides shaping, amplification and integration for the signals. This instrument needs to be qualified before being assembled on the detector. A PMT-Block test bench has been developed for this purpose. This test bench is a system which allows fast, albeit accurate enough, measurements of the main properties of a complete PMT-Block. The system, both hardware and software, and the protocol used for the PMT-Blocks characterization are described in detail in this report. The results obtained in the test of about 10
000 PMT-Blocks needed for the instrumentation of the ATLAS (LHC-CERN) hadronic Tile Calorimeter are also reported.
A measurement of the $ZZ$ production in the $\ell^{-}\ell^{+}\ell^{\prime -}\ell^{\prime +}$ and $\ell^{-}\ell^{+}\nu\bar{\nu}$ channels $(\ell = e, \mu)$ in proton--proton collisions at $\sqrt{s} = ...8$ TeV at the Large Hadron Collider at CERN, using data corresponding to an integrated luminosity of 20.3 fb$^{-1}$ collected by the ATLAS experiment in 2012 is presented. The fiducial cross sections for $ZZ\to\ell^{-}\ell^{+}\ell^{\prime -}\ell^{\prime +}$ and $ZZ\to \ell^{-}\ell^{+}\nu\bar{\nu}$ are measured in selected phase-space regions. The total cross section for $ZZ$ events produced with both $Z$ bosons in the mass range 66 to 116 GeV is measured from the combination of the two channels to be $7.3\pm0.4\textrm{(stat)}\pm0.3\textrm{(syst)}\pm0.2\textrm{(lumi)}$ pb, which is consistent with the Standard Model prediction of $6.6^{+0.7}_{-0.6}$ pb. The differential cross sections in bins of various kinematic variables are presented. The differential event yield as a function of the transverse momentum of the leading $Z$ boson is used to set limits on anomalous neutral triple gauge boson couplings in $ZZ$ production.
Two searches for new phenomena in final states containing a same-flavour opposite-lepton (electron or muon) pair, jets, and large missing transverse momentum are presented. These searches make use of ...proton--proton collision data, collected during 2015 and 2016 at a centre-of-mass energy $\sqrt{s}=13$ TeV by the ATLAS detector at the Large Hadron Collider, which correspond to an integrated luminosity of 14.7 fb$^{-1}$. Both searches target the pair production of supersymmetric particles, squarks or gluinos, which decay to final states containing a same-flavour opposite-sign lepton pair via one of two mechanisms: a leptonically decaying Z boson in the final state, leading to a peak in the dilepton invariant-mass distribution around the Z boson mass; and decays of neutralinos (e.g. $\tilde{\chi}_2^0 \rightarrow \ell^+\ell^- \tilde{\chi}_1^0$), yielding a kinematic endpoint in the dilepton invariant-mass spectrum. The data are found to be consistent with the Standard Model expectation. Results are interpreted in simplified models of gluino-pair (squark-pair) production, and provide sensitivity to gluinos (squarks) with masses as large as 1.70 TeV (980 GeV).
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A study of the decays B0→μ+μ− and B0s→μ+μ− has been performed using data corresponding to an integrated luminosity of 25 fb−1 of 7 TeV and 8 TeV proton--proton collisions collected with the ATLAS ...detector during the LHC Run 1. For B0, an upper limit on the branching fraction is set at B(B0→μ+μ−)<4.2×10−10 at 95% confidence level. For B0s, the branching fraction B(B0s→μ+μ−)=(0.9+1.1−0.8)×10−9 is measured. The results are consistent with the Standard Model expectation with a p-value of 4.8%, corresponding to 2.0 standard deviations.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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