CERN Accelerating science

A schematic diagram showing the first 6 planes of CalDet. In the configuration shown, CalDet was simultaneously instrumented with both ND and FD readout systems. Clear fibres are connected to the two upper manifolds and green WLS fibres to the two lowermanifolds.

Average calibrated energy deposited versus plane by $>$2~GeV/c test beam muons. The error bars show the statistical error, thus the jitter from point to point is indicative of systematic error in the uniformity calibration. The observed response spread of the points is 2.4\% and 3.0\% for the FD and NDreadout systems respectively.

Average non-linearity of the ND and FD readout systems versus the number of PE injected by the light injection calibration system. The difference in the non-linearity between the two readoutsystems can be clearly seen.

Transverse hit profile of $>$2~GeV/c test beam muons as measured with the ND (top) and FD (bottom) readout systems for data and MC\@. The central peak is mostly formed from strips that the muon actually passed through. Whereas, in contrast, the peaks towards the edges of the detector (strip number 0\,-\,3 and 20\,-\,23) are dominated by crosstalk hits. These data are fromplanes with strips that run horizontally.

Transverse hit profile of $>$2~GeV/c test beam muons as measured with the ND (top) and FD (bottom) readout systems for data and MC\@. The central peak is mostly formed from strips that the muon actually passed through. Whereas, in contrast, the peaks towards the edges of the detector (strip number 0\,-\,3 and 20\,-\,23) are dominated by crosstalk hits. These data are fromplanes with strips that run horizontally.

Average hit-by-hit asymmetry ratio, $<~\!\!\!A_{\mathcal N/ \mathcal F}^{Hit}\!\!\!~>$, as a function of the average energy deposition in the scintillator strip hit for data and MC\@. It can be seen that difference between the response of ND and FD readoutsystems changes by up to 2.5\% depending on the energy deposition.

Average event-by-event asymmetry ratio, $<~\!\!\!A_{\mathcal N/ \mathcal F}^{Event}\!\!\!~>$, as a function of the test beam momentum. The error bars show the total systematic error(statistical errors are negligible).

$<~\!\!\!A_{\mathcal N/ \mathcal F}^{Hit}\!\!\!~>$ computed with test beam through going muons along the detector axis (statistical errors only). Data exhibits a difference in $<~\!\!\!A_{\mathcal N/ \mathcal F}^{Hit}\!\!\!~>$ between the first third and the rest of the detector, which is consistent withcalibration systematic bias.

The readout system resolution (width of $A_{\mathcal N/ \mathcal F}^{Event}$) as a function of positron momentum. This figure demonstrates the size of the fluctuations that occur in the readout when the same physics event is observed by both Near and Far systems. It can be seen that the size of the fluctuations decreases with energy and is well reproduced by the MCsimulation.