CERN Accelerating science

A schematic view of the ATLAS inner detector. Radially outward from the collision point are the ATLAS insertable B-layer (IBL), the other layers of the pixel detector, the semiconductor microstrip tracker SCT, and the transition radiation tracker (TRT). A red curved line represents a charged particle traversing the various layers and bending in the 2~T magnetic field. The innermost pixel layer is called the Insertable $B$-Layer and was added to the detector between the first and second runs of the LHC.

A schematic view of the ATLAS inner detector. Radially outward from the collision point are the ATLAS insertable B-layer (IBL), the other layers of the pixel detector, the semiconductor microstrip tracker SCT, and the transition radiation tracker (TRT). A red curved line represents a charged particle traversing the various layers and bending in the 2~T magnetic field. The innermost pixel layer is called the Insertable $B$-Layer and was added to the detector between the first and second runs of the LHC.

Left: The best value of the effective silicon band-gap energy $(E_\text{eff}$) for use in normalizing silicon sensor leakage current to a temperature other than that at which it was recorded is investigated, for one module on the IBL. The top panel shows the temperature of the pixel detector module as set to several fixed values, and measured with the module temperature sensor. The lower panel shows the leakage current data as measured (black line) with a clear temperature dependence. Right: The optimal $E_\text{eff}$ value is determined for each module and then the average value is computed in bins of $z$ for each layer and disk. The vertical error bars represent the impact on the optimal $E_\text{eff}$ value due to a $\pm 2$\degC conservative uncertainty in the module temperature. Variations larger than this would be inconsistent with thermal models. Each bin is defined according to the average position of the modules whose data are used.

Left: The best value of the effective silicon band-gap energy $(E_\text{eff}$) for use in normalizing silicon sensor leakage current to a temperature other than that at which it was recorded is investigated, for one module on the IBL. The top panel shows the temperature of the pixel detector module as set to several fixed values, and measured with the module temperature sensor. The lower panel shows the leakage current data as measured (black line) with a clear temperature dependence. Right: The optimal $E_\text{eff}$ value is determined for each module and then the average value is computed in bins of $z$ for each layer and disk. The vertical error bars represent the impact on the optimal $E_\text{eff}$ value due to a $\pm 2$\degC conservative uncertainty in the module temperature. Variations larger than this would be inconsistent with thermal models. Each bin is defined according to the average position of the modules whose data are used.

Left: The best value of the effective silicon band-gap energy $(E_\text{eff}$) for use in normalizing silicon sensor leakage current to a temperature other than that at which it was recorded is investigated, for one module on the IBL. The top panel shows the temperature of the pixel detector module as set to several fixed values, and measured with the module temperature sensor. The lower panel shows the leakage current data as measured (black line) with a clear temperature dependence. Right: The optimal $E_\text{eff}$ value is determined for each module and then the average value is computed in bins of $z$ for each layer and disk. The vertical error bars represent the impact on the optimal $E_\text{eff}$ value due to a $\pm 2$\degC conservative uncertainty in the module temperature. Variations larger than this would be inconsistent with thermal models. Each bin is defined according to the average position of the modules whose data are used.

Left: The best value of the effective silicon band-gap energy $(E_\text{eff}$) for use in normalizing silicon sensor leakage current to a temperature other than that at which it was recorded is investigated, for one module on the IBL. The top panel shows the temperature of the pixel detector module as set to several fixed values, and measured with the module temperature sensor. The lower panel shows the leakage current data as measured (black line) with a clear temperature dependence. Right: The optimal $E_\text{eff}$ value is determined for each module and then the average value is computed in bins of $z$ for each layer and disk. The vertical error bars represent the impact on the optimal $E_\text{eff}$ value due to a $\pm 2$\degC conservative uncertainty in the module temperature. Variations larger than this would be inconsistent with thermal models. Each bin is defined according to the average position of the modules whose data are used.

The $\chi^2$ figure of merit is determined for a range of $E_\text{eff}$ values and variations of the module temperature data, for one module on the IBL. Steps of 0.01~\eV, in the range 0.5~\eV\ to 1.5~\eV, for $E_\text{eff}$ (a reduced range is shown for this model) and steps of 0.1\degC, in the range $-2.0$\degC to 2.0\degC, for the temperature variation are investigated independently. Here the definition of variation is the measured module temperature plus or minus a constant that corresponds to a systematic uncertainty in the temperature sensor reading. The measurement corresponds to data of integrated luminosity 161~fb$^{-1}$ delivered to the IBL.

The $\chi^2$ figure of merit is determined for a range of $E_\text{eff}$ values and variations of the module temperature data, for one module on the IBL. Steps of 0.01~\eV, in the range 0.5~\eV\ to 1.5~\eV, for $E_\text{eff}$ (a reduced range is shown for this model) and steps of 0.1\degC, in the range $-2.0$\degC to 2.0\degC, for the temperature variation are investigated independently. Here the definition of variation is the measured module temperature plus or minus a constant that corresponds to a systematic uncertainty in the temperature sensor reading. The measurement corresponds to data of integrated luminosity 161~fb$^{-1}$ delivered to the IBL.

The measured and predicted leakage currents for sensors on the Insertable $B$-layer, both normalized to 0\degC for four module groups spanning $|z|<8$~cm, $8<|z|<16$~cm, $16<|z|<24$~cm, and $24<|z|<32$~cm. Modules in the highest $|z|$ region use 3D sensors. The A and C sides of the detector ($z>0$ and $z<0$) are consistent with each other and averaged. The dominant time-independent uncertainty of 10\% is not included to avoid overlapping bands. The prediction is based on the thermal history of the modules combined with the Hamburg Model for modelling changes in the leakage current and \textsc{Pythia} + \textsc{Fluka} for simulating the overall fluence. For all four predictions, the overall scale normalization is based on a fit to the data across the entire range. Normalization factors are determined per $|z|$ region. The lower panel shows the ratio of the prediction to the data for the innermost module group. Similar MC/data trends are observed for the other three $|z|$ regions. For illustration, the fluence is shown as a lower horizontal axis using the nominal luminosity-to-fluence from simulation at $|z|=0$.

The measured and predicted leakage currents for sensors on the Insertable $B$-layer, both normalized to 0\degC for four module groups spanning $|z|<8$~cm, $8<|z|<16$~cm, $16<|z|<24$~cm, and $24<|z|<32$~cm. Modules in the highest $|z|$ region use 3D sensors. The A and C sides of the detector ($z>0$ and $z<0$) are consistent with each other and averaged. The dominant time-independent uncertainty of 10\% is not included to avoid overlapping bands. The prediction is based on the thermal history of the modules combined with the Hamburg Model for modelling changes in the leakage current and \textsc{Pythia} + \textsc{Fluka} for simulating the overall fluence. For all four predictions, the overall scale normalization is based on a fit to the data across the entire range. Normalization factors are determined per $|z|$ region. The lower panel shows the ratio of the prediction to the data for the innermost module group. Similar MC/data trends are observed for the other three $|z|$ regions. For illustration, the fluence is shown as a lower horizontal axis using the nominal luminosity-to-fluence from simulation at $|z|=0$.

The measured and predicted leakage currents on the Insertable $B$-layer, both normalized to 0\degC, divided by the currents in the 3D modules at $24<|z|<32$~cm. The other three module groups represent $|z|<8$~cm, $8<|z|<16$~cm, and $16<|z|<24$~cm. The A and C sides of the detector ($z>0$ and $z<0$) are consistent with each other and averaged. The dominant time-independent uncertainty of 10\% is not included to avoid overlapping bands. The prediction is based on the thermal history of the modules combined with the Hamburg Model for modelling changes in the leakage current and \textsc{Pythia} + \textsc{Fluka} for simulating the overall fluence. For all four predictions, the overall scale normalization is based on a fit to the data across the entire range. Normalization factors are determined per $|z|$ region. The lower panel shows the ratio of the prediction to the data for the innermost module group. Similar MC/data trends are observed for the other three $|z|$ regions. For illustration, the fluence is shown as a lower horizontal axis using the nominal luminosity-to-fluence from simulation at $|z|=0$.

The measured and predicted leakage currents on the Insertable $B$-layer, both normalized to 0\degC, divided by the currents in the 3D modules at $24<|z|<32$~cm. The other three module groups represent $|z|<8$~cm, $8<|z|<16$~cm, and $16<|z|<24$~cm. The A and C sides of the detector ($z>0$ and $z<0$) are consistent with each other and averaged. The dominant time-independent uncertainty of 10\% is not included to avoid overlapping bands. The prediction is based on the thermal history of the modules combined with the Hamburg Model for modelling changes in the leakage current and \textsc{Pythia} + \textsc{Fluka} for simulating the overall fluence. For all four predictions, the overall scale normalization is based on a fit to the data across the entire range. Normalization factors are determined per $|z|$ region. The lower panel shows the ratio of the prediction to the data for the innermost module group. Similar MC/data trends are observed for the other three $|z|$ regions. For illustration, the fluence is shown as a lower horizontal axis using the nominal luminosity-to-fluence from simulation at $|z|=0$.

Average measured leakage current of a representative sample of modules on the $B$-Layer, Layer-1 and Layer-2 over the full period of operation. The scaled prediction from the Hamburg Model is also shown. The bands include uncertainties on the measurement, as described in Sec.~\ref{sec:outeruncerts}.

Average measured leakage current of a representative sample of modules on the $B$-Layer, Layer-1 and Layer-2 over the full period of operation. The scaled prediction from the Hamburg Model is also shown. The bands include uncertainties on the measurement, as described in Sec.~\ref{sec:outeruncerts}.

Ratios of the $B$-Layer and Layer-1 leakage current data to Layer-2 leakage current for the LHC Run~2 period of ATLAS operation. The bands include uncertainties on the measurement, as described in Sec.~\ref{sec:outeruncerts}

Ratios of the $B$-Layer and Layer-1 leakage current data to Layer-2 leakage current for the LHC Run~2 period of ATLAS operation. The bands include uncertainties on the measurement, as described in Sec.~\ref{sec:outeruncerts}

Typical time evolution of normalized leakage currents in the four SCT modules groups, one each from B3, B6, EC-C and EC-A regions. Top plots show histories of deduced sensor temperatures, while the second plots are leakage current data and Hamburg Model predictions. Each data point represents an average of time-weighted leakage current means over 30--56 modules in a single physics or calibration run. The two bottom plots show the ratios of data to predictions from the Hamburg and Sheffield models, using the same conversion factors as in \textsc{Fluka} transport simulations. Coloured bands show 1$\sigma$ uncertainties of the model predictions.

Typical time evolution of normalized leakage currents in the four SCT modules groups, one each from B3, B6, EC-C and EC-A regions. Top plots show histories of deduced sensor temperatures, while the second plots are leakage current data and Hamburg Model predictions. Each data point represents an average of time-weighted leakage current means over 30--56 modules in a single physics or calibration run. The two bottom plots show the ratios of data to predictions from the Hamburg and Sheffield models, using the same conversion factors as in \textsc{Fluka} transport simulations. Coloured bands show 1$\sigma$ uncertainties of the model predictions.

Typical time evolution of normalized leakage currents in the four SCT modules groups, one each from B3, B6, EC-C and EC-A regions. Top plots show histories of deduced sensor temperatures, while the second plots are leakage current data and Hamburg Model predictions. Each data point represents an average of time-weighted leakage current means over 30--56 modules in a single physics or calibration run. The two bottom plots show the ratios of data to predictions from the Hamburg and Sheffield models, using the same conversion factors as in \textsc{Fluka} transport simulations. Coloured bands show 1$\sigma$ uncertainties of the model predictions.

Typical time evolution of normalized leakage currents in the four SCT modules groups, one each from B3, B6, EC-C and EC-A regions. Top plots show histories of deduced sensor temperatures, while the second plots are leakage current data and Hamburg Model predictions. Each data point represents an average of time-weighted leakage current means over 30--56 modules in a single physics or calibration run. The two bottom plots show the ratios of data to predictions from the Hamburg and Sheffield models, using the same conversion factors as in \textsc{Fluka} transport simulations. Coloured bands show 1$\sigma$ uncertainties of the model predictions.

Typical time evolution of normalized leakage currents in the four SCT modules groups, one each from B3, B6, EC-C and EC-A regions. Top plots show histories of deduced sensor temperatures, while the second plots are leakage current data and Hamburg Model predictions. Each data point represents an average of time-weighted leakage current means over 30--56 modules in a single physics or calibration run. The two bottom plots show the ratios of data to predictions from the Hamburg and Sheffield models, using the same conversion factors as in \textsc{Fluka} transport simulations. Coloured bands show 1$\sigma$ uncertainties of the model predictions.

Typical time evolution of normalized leakage currents in the four SCT modules groups, one each from B3, B6, EC-C and EC-A regions. Top plots show histories of deduced sensor temperatures, while the second plots are leakage current data and Hamburg Model predictions. Each data point represents an average of time-weighted leakage current means over 30--56 modules in a single physics or calibration run. The two bottom plots show the ratios of data to predictions from the Hamburg and Sheffield models, using the same conversion factors as in \textsc{Fluka} transport simulations. Coloured bands show 1$\sigma$ uncertainties of the model predictions.

Typical time evolution of normalized leakage currents in the four SCT modules groups, one each from B3, B6, EC-C and EC-A regions. Top plots show histories of deduced sensor temperatures, while the second plots are leakage current data and Hamburg Model predictions. Each data point represents an average of time-weighted leakage current means over 30--56 modules in a single physics or calibration run. The two bottom plots show the ratios of data to predictions from the Hamburg and Sheffield models, using the same conversion factors as in \textsc{Fluka} transport simulations. Coloured bands show 1$\sigma$ uncertainties of the model predictions.

Typical time evolution of normalized leakage currents in the four SCT modules groups, one each from B3, B6, EC-C and EC-A regions. Top plots show histories of deduced sensor temperatures, while the second plots are leakage current data and Hamburg Model predictions. Each data point represents an average of time-weighted leakage current means over 30--56 modules in a single physics or calibration run. The two bottom plots show the ratios of data to predictions from the Hamburg and Sheffield models, using the same conversion factors as in \textsc{Fluka} transport simulations. Coloured bands show 1$\sigma$ uncertainties of the model predictions.

Leakage current measured at HV set to 150~V normalized to 0\degC per unit volume for all (a) barrel modules and (b) endcap modules as of November 1, 2018. At the same $r$ and $z$ location, modules with different $\phi$ indices are arranged horizontally from left ($\phi=0^\circ$) to right ($\phi=360^\circ$). Endcap side-A and side-C as well as sensor manufacturers (Hamamatsu (HPK) and CiS) are plotted in different colours. Horizontal solid/dot-dash bars indicate model predictions of the Hamburg Model using the conversion factors by \textsc{Fluka} (solid) / \textsc{Geant} (dot-dash) transport simulations. In the two ratio plots, mean and RMS values via Gaussian fits of modules belonging to the same group are plotted. The model uncertainties are shown by blue bands.

Leakage current measured at HV set to 150~V normalized to 0\degC per unit volume for all (a) barrel modules and (b) endcap modules as of November 1, 2018. At the same $r$ and $z$ location, modules with different $\phi$ indices are arranged horizontally from left ($\phi=0^\circ$) to right ($\phi=360^\circ$). Endcap side-A and side-C as well as sensor manufacturers (Hamamatsu (HPK) and CiS) are plotted in different colours. Horizontal solid/dot-dash bars indicate model predictions of the Hamburg Model using the conversion factors by \textsc{Fluka} (solid) / \textsc{Geant} (dot-dash) transport simulations. In the two ratio plots, mean and RMS values via Gaussian fits of modules belonging to the same group are plotted. The model uncertainties are shown by blue bands.

Leakage current measured at HV set to 150~V normalized to 0\degC per unit volume for all (a) barrel modules and (b) endcap modules as of November 1, 2018. At the same $r$ and $z$ location, modules with different $\phi$ indices are arranged horizontally from left ($\phi=0^\circ$) to right ($\phi=360^\circ$). Endcap side-A and side-C as well as sensor manufacturers (Hamamatsu (HPK) and CiS) are plotted in different colours. Horizontal solid/dot-dash bars indicate model predictions of the Hamburg Model using the conversion factors by \textsc{Fluka} (solid) / \textsc{Geant} (dot-dash) transport simulations. In the two ratio plots, mean and RMS values via Gaussian fits of modules belonging to the same group are plotted. The model uncertainties are shown by blue bands.

Leakage current measured at HV set to 150~V normalized to 0\degC per unit volume for all (a) barrel modules and (b) endcap modules as of November 1, 2018. At the same $r$ and $z$ location, modules with different $\phi$ indices are arranged horizontally from left ($\phi=0^\circ$) to right ($\phi=360^\circ$). Endcap side-A and side-C as well as sensor manufacturers (Hamamatsu (HPK) and CiS) are plotted in different colours. Horizontal solid/dot-dash bars indicate model predictions of the Hamburg Model using the conversion factors by \textsc{Fluka} (solid) / \textsc{Geant} (dot-dash) transport simulations. In the two ratio plots, mean and RMS values via Gaussian fits of modules belonging to the same group are plotted. The model uncertainties are shown by blue bands.

The leakage current at the end of Run~2 (left) and the fluence rate (right) as a function of $z$ for the silicon-based parts of the ATLAS inner detector. The predicted values are symmetric in $z$ by construction. Distances given in parentheses after layer names correspond to the radial positions of the sensors relative to the geometric centre of ATLAS. For the IBL, the error bars are dominated by the residual dependence of the leakage current on the high voltage past full depletion; for the outer layers of the pixel detector, the uncertainty is dominated by a power supply uncertainty and uncertainties in the temperature and luminosity; for the SCT, the uncertainty is due to the sensor temperature, the luminosity, and the sensor thickness (for fluence) and the RMS spread across modules (leakage current). Uncertainties in the silicon damage factors (relevant for the simulation and the Hamburg Model) are not included.

The leakage current at the end of Run~2 (left) and the fluence rate (right) as a function of $z$ for the silicon-based parts of the ATLAS inner detector. The predicted values are symmetric in $z$ by construction. Distances given in parentheses after layer names correspond to the radial positions of the sensors relative to the geometric centre of ATLAS. For the IBL, the error bars are dominated by the residual dependence of the leakage current on the high voltage past full depletion; for the outer layers of the pixel detector, the uncertainty is dominated by a power supply uncertainty and uncertainties in the temperature and luminosity; for the SCT, the uncertainty is due to the sensor temperature, the luminosity, and the sensor thickness (for fluence) and the RMS spread across modules (leakage current). Uncertainties in the silicon damage factors (relevant for the simulation and the Hamburg Model) are not included.

The leakage current at the end of Run~2 (left) and the fluence rate (right) as a function of $\eta$ for the silicon-based parts of the ATLAS inner detector. The predicted values are symmetric in $\eta$ by construction. Distances given in parentheses after layer names correspond to the radial positions of the sensors relative to the geometric centre of ATLAS. For the IBL, the error bars are dominated by the residual dependence of the leakage current on the high voltage past full depletion; for the outer layers of the pixel detector, the uncertainty is dominated by a power supply uncertainty and uncertainties in the temperature and luminosity; for the SCT, the uncertainty is due to the sensor temperature, the luminosity, and the sensor thickness (for fluence) and the RMS spread across modules (leakage current). Uncertainties in the silicon damage factors (relevant for the simulation and the Hamburg Model) are not included.

The leakage current at the end of Run~2 (left) and the fluence rate (right) as a function of $\eta$ for the silicon-based parts of the ATLAS inner detector. The predicted values are symmetric in $\eta$ by construction. Distances given in parentheses after layer names correspond to the radial positions of the sensors relative to the geometric centre of ATLAS. For the IBL, the error bars are dominated by the residual dependence of the leakage current on the high voltage past full depletion; for the outer layers of the pixel detector, the uncertainty is dominated by a power supply uncertainty and uncertainties in the temperature and luminosity; for the SCT, the uncertainty is due to the sensor temperature, the luminosity, and the sensor thickness (for fluence) and the RMS spread across modules (leakage current). Uncertainties in the silicon damage factors (relevant for the simulation and the Hamburg Model) are not included.

The leakage current at the end of Run~2 (left) and the fluence rate (right) as a function of radius for the silicon-based parts of the ATLAS inner detector. The length of the horizontal bands representing the simulation is chosen to aid the comparison with data -- the actual radial uncertainty from the finite size of the sensors is comparable to the marker sizes. For the IBL, the error bars are dominated by the residual dependence of the leakage current on the high voltage past full depletion; for the outer layers of the pixel detector, the uncertainty is dominated by a power supply uncertainty and uncertainties in the temperature and luminosity; for the SCT, the uncertainty is due to the sensor temperature, the luminosity, and the sensor thickness (for fluence) and the RMS spread across modules (leakage current). Uncertainties in the silicon damage factors (relevant for the simulation and the Hamburg Model) are not included.

The leakage current at the end of Run~2 (left) and the fluence rate (right) as a function of radius for the silicon-based parts of the ATLAS inner detector. The length of the horizontal bands representing the simulation is chosen to aid the comparison with data -- the actual radial uncertainty from the finite size of the sensors is comparable to the marker sizes. For the IBL, the error bars are dominated by the residual dependence of the leakage current on the high voltage past full depletion; for the outer layers of the pixel detector, the uncertainty is dominated by a power supply uncertainty and uncertainties in the temperature and luminosity; for the SCT, the uncertainty is due to the sensor temperature, the luminosity, and the sensor thickness (for fluence) and the RMS spread across modules (leakage current). Uncertainties in the silicon damage factors (relevant for the simulation and the Hamburg Model) are not included.