CERN Accelerating science

Sketch of one AHCAL module (left). The scintillator tiles with SiPM readout are embedded in a steel cassette. The SiPM signal is routed to the VFE electronics located on the right side. The calibration and monitoring board (CMB), located on the left side, provides UV LED light for calibration and the CAN-BUS readout for temperature sensors located inside the cassette and on the electronics (red dots). Picture of one active layer of the CALICE AHCAL prototype (right).

Sketch of one AHCAL module (left). The scintillator tiles with SiPM readout are embedded in a steel cassette. The SiPM signal is routed to the VFE electronics located on the right side. The calibration and monitoring board (CMB), located on the left side, provides UV LED light for calibration and the CAN-BUS readout for temperature sensors located inside the cassette and on the electronics (red dots). Picture of one active layer of the CALICE AHCAL prototype (right).

Single photoelectron peak spectrum taken with a SiPM in the AHCAL detector.

Gain calibration efficiency (left) and electronics inter-calibration efficiency (right) over the AHCAL data taking period at CERN in 2007 (red dots) and at FNAL in 2008 (open blue triangles). More than 85.0\,\% of the channels could be monitored for gain and inter-calibration variation during these periods.

Gain calibration efficiency (left) and electronics inter-calibration efficiency (right) over the AHCAL data taking period at CERN in 2007 (red dots) and at FNAL in 2008 (open blue triangles). More than 85.0\,\% of the channels could be monitored for gain and inter-calibration variation during these periods.

The SiPM response function (left) and the saturation correction function, $f_{\rm{sat}}$, applied in the data calibration chain (right).

Ratio of maximum number of fired pixels, $N_{\rm tot}$(mounted), measured with SiPM mounted on a tile to $N_{\rm tot}$(bare) measured directly with bare SiPMs.

Top view of the CERN beam test setup. The plot shows the instrumentation in 2007. The beam enters from the left side. See text for explanations of the components.

Hit energy spectrum for 40\,GeV positron showers compared to that of 40\,GeV and 80\,GeV pion showers from a {\sc Geant}4 simulation.

The shower energy is summed up in a cylinder (left); see text for details. Spectra of the energy sum for positron data with energy between 10 GeV and 45 GeV (right). For each spectrum the mean energy response in units of MIP, $E_{\rm{mean}}$, is obtained with a Gaussian fit in the range $\pm 2\sigma$.

The shower energy is summed up in a cylinder (left); see text for details. Spectra of the energy sum for positron data with energy between 10 GeV and 45 GeV (right). For each spectrum the mean energy response in units of MIP, $E_{\rm{mean}}$, is obtained with a Gaussian fit in the range $\pm 2\sigma$.

Reconstructed energy of a 10\,GeV positrons for data (black dots) and for Monte Carlo (filled yellow histogram), as well as a Gaussian fit to data (blue line).

noimgAHCAL energy reconstructed in data and MC (in units of GeV) for various positron beam energies. The table reports the values plotted in Figure~10. The systematic uncertainties for data are detailed in their percentage values. The total absolute error $\Delta_E^{\rm tot}$ is the sum in quadrature of the uncertainties on the MIP, on the SiPM gain and on the saturation point determination.

Linearity of the AHCAL response to positrons in the range 10--50\,GeV. The blue dotted line shows the exact linearity. Black dots correspond to data corrected for SiPM non-linear response, blue triangles show the data before this correction, and the open red triangles show the simulation. The green band indicates the systematic uncertainty as quoted in Table~1, $\Delta_E^{\rm tot}$ [GeV].

Residual to a fit of the data and Monte Carlo points presented in Figure~\ref{em_linearity} using, a linear function ($y=ax$) (left), a line fit ($y=ax+b$) (right), in the range 10--50\,GeV. Black dots correspond to data, and open red triangles to simulation. The green band indicates the sum in quadrature of the energy dependent systematic uncertainties, $\delta_E^{\rm Gain}$ and $\delta_E^{\rm sat}$ in Table~1.

Residual to a fit of the data and Monte Carlo points presented in Figure~\ref{em_linearity} using, a linear function ($y=ax$) (left), a line fit ($y=ax+b$) (right), in the range 10--50\,GeV. Black dots correspond to data, and open red triangles to simulation. The green band indicates the sum in quadrature of the energy dependent systematic uncertainties, $\delta_E^{\rm Gain}$ and $\delta_E^{\rm sat}$ in Table~1.

Hit energy spectrum for 30\,GeV positron showers in the AHCAL. Open circles (black dots) show the data before (after) correction for the non-linear response of the SiPM. The insert shows the hit distribution in a linear scale.

Energy resolution of the AHCAL for positrons (black circles). The resolution agrees with that of a previous prototype (black triangles) with the same sampling structure. The errors are the quadratic sum of statistics and systematic uncertainties.

Longitudinal profile of a 10\,GeV positron shower in units of $X_0$ (left) and scaling of the shower maximum as a function of the incident energy (right). The reconstructed energy (left plot) is shown for data (solid points), simulation (yellow-shaded area) and a fit to the data using Eq.~4.2 (black line). The bottom insert shows the data/Monte Carlo comparison. The shower maximum (right plot) is shown for data (solid points), simulation (red open triangles) and the theory expectation given in Eq.~4.3 (blue solid line).

Longitudinal profile of a 10\,GeV positron shower in units of $X_0$ (left) and scaling of the shower maximum as a function of the incident energy (right). The reconstructed energy (left plot) is shown for data (solid points), simulation (yellow-shaded area) and a fit to the data using Eq.~4.2 (black line). The bottom insert shows the data/Monte Carlo comparison. The shower maximum (right plot) is shown for data (solid points), simulation (red open triangles) and the theory expectation given in Eq.~4.3 (blue solid line).

Transverse profile of a 15 GeV positron shower. The energy density is shown in 10 mm wide concentric rings centered around the shower axis.

Mean (left) and RMS (right) of the transverse shower distribution as a function of beam energy. Black dots correspond to data and red open triangles correspond to Monte Carlo.

Mean (left) and RMS (right) of the transverse shower distribution as a function of beam energy. Black dots correspond to data and red open triangles correspond to Monte Carlo.

Schematic view of tile positions in an AHCAL scintillator plane used for the uniformity test (left) and uniformity of the calorimeter response for various positions of incident beam with respect to the detector (right). Tile position eight is approximately in the center of each calorimeter layer. The dashed lines show the systematic uncertainties. Statistical errors are negligible.

Schematic view of tile positions in an AHCAL scintillator plane used for the uniformity test (left) and uniformity of the calorimeter response for various positions of incident beam with respect to the detector (right). Tile position eight is approximately in the center of each calorimeter layer. The dashed lines show the systematic uncertainties. Statistical errors are negligible.

Schematic view of the AHCAL rotated with respect to the beam (left) and reconstructed energy of 10 GeV positrons normalized to the average versus angle of incidence (right). To improve legibility, the data (solid points) and the simulation (red triangles) are slightly shifted in opposite directions on the abscissa. The systematic uncertainty is shown by dash-dotted lines. Additionally, the spread of all measurements performed at one inclination angle are shown as an error for each point.

Schematic view of the AHCAL rotated with respect to the beam (left) and reconstructed energy of 10 GeV positrons normalized to the average versus angle of incidence (right). To improve legibility, the data (solid points) and the simulation (red triangles) are slightly shifted in opposite directions on the abscissa. The systematic uncertainty is shown by dash-dotted lines. Additionally, the spread of all measurements performed at one inclination angle are shown as an error for each point.

Picture of the scintillating tile (left). Effect of the AHCAL scintillator tile structure on the energy measurement (summed over the entire calorimeter) for 10 GeV electromagnetic showers (right).

Picture of the scintillating tile (left). Effect of the AHCAL scintillator tile structure on the energy measurement (summed over the entire calorimeter) for 10 GeV electromagnetic showers (right).