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Schematic view of one quadrant of the SCT. The numbering schemes for the barrel layers and endcap disks are shown, together with the radial and longitudinal coordinates. The disks comprise up to three rings of modules, referred to as inner, middle and outer, at increasing radii from the beam-pipe. The detector is symmetric between Side-A (positive $z$) and Side-C (negative $z$).
Schematic view of one quadrant of the SCT. The numbering schemes for the barrel layers and endcap disks are shown, together with the radial and longitudinal coordinates. The disks comprise up to three rings of modules, referred to as inner, middle and outer, at increasing radii from the beam-pipe. The detector is symmetric between Side-A (positive $z$) and Side-C (negative $z$).
Event display projected onto the $r$--$\phi$ plane, taken by an unbiased random trigger in a typical $pp$ collision run at $\sqrt{s} = 13$~\TeV\ in May 2018. This event has approximately 60 $pp$ interactions, which is nearly the maximum experienced in Run~2. The outer four circles correspond to the four barrel layers of the SCT, while the inner four circles are the Pixel and IBL layers. The lines emerging almost radially from the centre (interaction point) represent reconstructed tracks of charged particles with transverse momentum greater than 0.5~\GeV.
Event display projected onto the $r$--$\phi$ plane, taken by an unbiased random trigger in a typical $pp$ collision run at $\sqrt{s} = 13$~\TeV\ in May 2018. This event has approximately 60 $pp$ interactions, which is nearly the maximum experienced in Run~2. The outer four circles correspond to the four barrel layers of the SCT, while the inner four circles are the Pixel and IBL layers. The lines emerging almost radially from the centre (interaction point) represent reconstructed tracks of charged particles with transverse momentum greater than 0.5~\GeV.
Schematic diagram of the SCT DAQ~\cite{IDET-2013-01}.
Schematic diagram of the SCT DAQ~\cite{IDET-2013-01}.
Fraction of ABCD chip errors as a function of average pile-up, $\mu$, times the level-1 trigger rate for a module using RX redundancy. The black dots are from 2016, before introduction of the chip-masking mechanism, while the red squares are from 2017 with chip masking. Changes for the set of masked chips are visible as steps in the ABCD error fraction around $\mu \sim 30$ and 40. The significant peaks at $\mu \sim 4$ and $15$ are due to a chip which was transiently very noisy.
Fraction of ABCD chip errors as a function of average pile-up, $\mu$, times the level-1 trigger rate for a module using RX redundancy. The black dots are from 2016, before introduction of the chip-masking mechanism, while the red squares are from 2017 with chip masking. Changes for the set of masked chips are visible as steps in the ABCD error fraction around $\mu \sim 30$ and 40. The significant peaks at $\mu \sim 4$ and $15$ are due to a chip which was transiently very noisy.
Number of FE-links exceeding the bandwidth limitation as a function of $\mu$, at a level-1 trigger rate of 100~kHz. In the nominal configuration (black curve at right), signals are read out by two FE-links and therefore one FE-link transmits signals from up to six ABCD chips. For the FE-links using RX redundancy, where one FE-link transmits signals from up to 12 ABCD chips on a module, the dashed middle (solid left) curve corresponds to the case with chip masking enabled (disabled).
Number of FE-links exceeding the bandwidth limitation as a function of $\mu$, at a level-1 trigger rate of 100~kHz. In the nominal configuration (black curve at right), signals are read out by two FE-links and therefore one FE-link transmits signals from up to six ABCD chips. For the FE-links using RX redundancy, where one FE-link transmits signals from up to 12 ABCD chips on a module, the dashed middle (solid left) curve corresponds to the case with chip masking enabled (disabled).
Number of S-links operating above the bandwidth occupancy threshold specified on the $x$-axis. During operation, once the S-link occupancy exceeds 90\% of its bandwidth, the corresponding ROD starts to fall into the busy state, so that it becomes impossible to transfer data correctly. The bandwidth occupancy of each configuration in 2012 (green line, right), 2015 (dashed black, middle) and 2016 (blue, left) is simulated using the extreme condition of a level-1 trigger rate of 100~kHz with $\mu = 60$. The line labelled 2012 shows the 90-ROD system used in Run~1, where many S-links were not able to handle the high data rate. Several S-links for endcap modules showed significantly higher occupancy than the other S-links, due to an imbalanced distribution of data rate per ROD. These features were significantly improved in the 2015 configuration with 128 RODs. In 2016 the supercondensed mode was introduced and the FE-link remapping was performed, in order to distribute the S-link occupancy more uniformly.
Number of S-links operating above the bandwidth occupancy threshold specified on the $x$-axis. During operation, once the S-link occupancy exceeds 90\% of its bandwidth, the corresponding ROD starts to fall into the busy state, so that it becomes impossible to transfer data correctly. The bandwidth occupancy of each configuration in 2012 (green line, right), 2015 (dashed black, middle) and 2016 (blue, left) is simulated using the extreme condition of a level-1 trigger rate of 100~kHz with $\mu = 60$. The line labelled 2012 shows the 90-ROD system used in Run~1, where many S-links were not able to handle the high data rate. Several S-links for endcap modules showed significantly higher occupancy than the other S-links, due to an imbalanced distribution of data rate per ROD. These features were significantly improved in the 2015 configuration with 128 RODs. In 2016 the supercondensed mode was introduced and the FE-link remapping was performed, in order to distribute the S-link occupancy more uniformly.
Evolution of the number of noisy chips in a run with and without global reconfiguration activated, for two typical runs in Run~2.
Evolution of the number of noisy chips in a run with and without global reconfiguration activated, for two typical runs in Run~2.
Evolution of the fraction of noisy strips as a function of date, including both Run~1 and Run~2. Each point corresponds to one run.
Evolution of the fraction of noisy strips as a function of date, including both Run~1 and Run~2. Each point corresponds to one run.
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Interstrip hit efficiency as a function of relative $x$, the distance from one strip towards the next, with $\phiin = -5\degr$. The measurement is performed using data from a low-pile-up run in July 2018. Only modules with $|\etaindex| = 1$ are used. All possible interstrip combinations are averaged. The blue shaded regions near 0 and 80~$\mu$m correspond to the strip implant positions.
Interstrip hit efficiency as a function of relative $x$, the distance from one strip towards the next, with $\phiin = -5\degr$. The measurement is performed using data from a low-pile-up run in July 2018. Only modules with $|\etaindex| = 1$ are used. All possible interstrip combinations are averaged. The blue shaded regions near 0 and 80~$\mu$m correspond to the strip implant positions.
Hit efficiency as a function of HV for modules with $|\etaindex| = 1$ in barrel layer 3, measured from November 2015 to September 2018.
Hit efficiency as a function of HV for modules with $|\etaindex| = 1$ in barrel layer 3, measured from November 2015 to September 2018.
Cluster width distributions in the four barrel layers, measured from a $pp$ collision run in November 2015 at a HV of 150~V.
Cluster width distributions in the four barrel layers, measured from a $pp$ collision run in November 2015 at a HV of 150~V.
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Time dependence of $\phiMCW$ between 2015 and 2018 in barrel layer~3. Only the sides with no stereo angle are shown. The error bars are statistical, while the shaded bands show the systematic uncertainties. The time when the nominal operational HV was raised from 150~V to 250~V is indicated by the vertical dashed line.
Time dependence of $\phiMCW$ between 2015 and 2018 in barrel layer~3. Only the sides with no stereo angle are shown. The error bars are statistical, while the shaded bands show the systematic uncertainties. The time when the nominal operational HV was raised from 150~V to 250~V is indicated by the vertical dashed line.
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: Distributions of chip-averaged \protect\subref{fig:chip_noise:a} response-curve noise, \protect\subref{fig:chip_noise:b} noise occupancy and \protect\subref{fig:chip_noise:c} amplifier gain. Data from February or March 2015 (top) and from September or November 2018 (bottom) are compared for different types of modules. For the barrel, only modules with sensors of crystal orientation <111> are plotted; barrel layer~6, which has a higher temperature and thus higher noise, is shown separately. Other barrel modules are combined regardless of the layer because there is no significant difference. For the endcaps, chips reading out HPK and CiS sensors are shown separately.
: Distributions of chip-averaged \protect\subref{fig:chip_noise:a} response-curve noise, \protect\subref{fig:chip_noise:b} noise occupancy and \protect\subref{fig:chip_noise:c} amplifier gain. Data from February or March 2015 (top) and from September or November 2018 (bottom) are compared for different types of modules. For the barrel, only modules with sensors of crystal orientation <111> are plotted; barrel layer~6, which has a higher temperature and thus higher noise, is shown separately. Other barrel modules are combined regardless of the layer because there is no significant difference. For the endcaps, chips reading out HPK and CiS sensors are shown separately.
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Simulated map of the 1-\MeV-neutron equivalent fluence per fb$^{-1}$ of integrated luminosity at 13~\TeV\ centre-of-mass energy around the ID region with the ATLAS Run-2 detector geometry.
Simulated map of the 1-\MeV-neutron equivalent fluence per fb$^{-1}$ of integrated luminosity at 13~\TeV\ centre-of-mass energy around the ID region with the ATLAS Run-2 detector geometry.
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Evolution of normalised leakage currents for four groups of modules: from left to right, barrel layer~3 (modules at $\etaindex = 1$), barrel layer~6 (modules at $\etaindex = 6$), endcap~C (outer ring of disk~9) and endcap~A (inner ring of disk~5). The main plots show leakage current data (red points) compared with predictions from the Hamburg model (blue line with uncertainty bands). Data points were measured during physics runs or in SCT stand-alone calibration runs. The lower two sets of plots show ratios of data to model predictions from the Hamburg and Sheffield models. Both models use the same conversion factors estimated from \textsc{Fluka} and \GEANT transport simulations. Coloured bands correspond to $\pm1\sigma$ uncertainties in the model prediction, but uncertainties from the \textsc{Fluka} simulation are not included.
Evolution of normalised leakage currents for four groups of modules: from left to right, barrel layer~3 (modules at $\etaindex = 1$), barrel layer~6 (modules at $\etaindex = 6$), endcap~C (outer ring of disk~9) and endcap~A (inner ring of disk~5). The main plots show leakage current data (red points) compared with predictions from the Hamburg model (blue line with uncertainty bands). Data points were measured during physics runs or in SCT stand-alone calibration runs. The lower two sets of plots show ratios of data to model predictions from the Hamburg and Sheffield models. Both models use the same conversion factors estimated from \textsc{Fluka} and \GEANT transport simulations. Coloured bands correspond to $\pm1\sigma$ uncertainties in the model prediction, but uncertainties from the \textsc{Fluka} simulation are not included.
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Distributions of $\vfd$ for modules in the four barrel layers. From top to bottom, results from November 2011, March 2017 and November 2018 are shown.
Distributions of $\vfd$ for modules in the four barrel layers. From top to bottom, results from November 2011, March 2017 and November 2018 are shown.
Evolution of $\vfd$ estimated from the $I$--$V$ curves. From left to right, results from barrel layer~3, outer ring of endcap disk~9 and inner ring of endcap disk~6 are shown. Green points show initial values of $\vfd$ determined from $C$--$V$ measurements. Predictions from the Hamburg model are shown by lines with model uncertainty bands for standard (red) and oxygenated (blue) silicon sensors.
Evolution of $\vfd$ estimated from the $I$--$V$ curves. From left to right, results from barrel layer~3, outer ring of endcap disk~9 and inner ring of endcap disk~6 are shown. Green points show initial values of $\vfd$ determined from $C$--$V$ measurements. Predictions from the Hamburg model are shown by lines with model uncertainty bands for standard (red) and oxygenated (blue) silicon sensors.