Setup of a Drift Tube Muon Tracker and Calibration of Muon ...

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Zenith Angle CMT and BX-GL Tracks h_theta_glEntries 12535Mean 1.411RMS 8.752302 χ / ndf 18.3 / 15norm 290.2 ± 29.5mean 1.1 ± 0.425σ 4.008 ± 0.407N per 3°N per 6°Azimuth Angle CMT and BX-GL Tracks h_phi_glEntries 12525Mean -1.72320RMS 26.12χ 2 / ndf 31.46 / 19norm 393.2 ± 48.6mean 0.9893 ± 1.2160σ 9.035 ± 1.4652015151051050-40 -30 -20 -10 0 10 20 30 40∆θ [°]0-80 -60 -40 -20 0 20 40 60 80∆ϕ [°]Figure 5.20: Comparison of reconstructed polar and azimuth angles for the CMTand Borexino global tracking.collected CMT data has been compared to all three tracking methods. Since theCMT resolution exceeds the Borexino resolution by far, the CMT track coordinatesare considered to be the true track coordinates. Hence, the resolution of the Borexinotracking can be determined by a comparison.Due to the low trigger efficiency, only 392 common events of the CMT andBorexino remain. The event sample had to be reduced further. Some of the eventscome from multiple muon hits as depicted in Fig. 5.17, where a 3D reconstructioncannot be done without ambiguities. Therefore these events were not used in theanalysis. Also, many events are ignored due to the cut on the number of used hitsintroduced in Section 5.2.1. However, most of these events can be used once a bettercalibration is feasible. In addition to the reduction of events due to the CMT dataquality, not all events with a BX flag have an according reconstructed muon trackin Borexino. But although the overall statistics are rather poor they allow to do afirst comparison of the combined data.For the analysis, both the angular and lateral resolution have been determined.For each common event, track parameters like the polar angle θ and the azimuthangle ϕ were compared. Fig. 5.20 shows the distribution of ∆θ and ∆ϕ obtainedfrom the differences between the CMT and the Borexino global tracking. A clearpeak around 0 can be observed for both distributions. The peaks have been fitted bya Gaussian and the resulting σ gives a measure for the angular resolution. Results forall tracking algorithms are presented in Tab. 5.6. The values mostly range between3 and 9 degrees.Instead of looking at the polar and azimuth angles, one can also investigate theintermediate angle α between the tracks ⃗t i from the different reconstructions. It issimply given by⃗t bx ·⃗t cmt = |⃗t bx ||⃗t cmt |cos α⇔α = cos −1 (sin θ bx sin θ cmt (cos ϕ bx cos ϕ cmt + sin ϕ bx sin ϕ cmt ) + cos θ bx cos θ cmt ) .An exemplary plot for the distribution of intermediate angles between the CMT andBorexino global tracking is shown in Fig. 5.21. The values have been weighted by88
Table 5.6: Angular and lateral resolutions σ resulting from the track comparison ofthe CMT to the different Borexino trackings.σ θ [ ◦ ] σ ϕ [ ◦ ] σ α [ ◦ ] σ x [cm] σ y [cm] σ I [cm] ¯dI [cm]OD 3.0 ± 0.3 9.1 ± 1.3 4.00 ± 0.09 62 ± 4 62 ± 4 50 ± 2 77 ± 12ID 6.6 ± 1.1 25 ± 5 4.64 ± 0.16 67 ± 6 34 ± 3 48 ± 5 75 ± 9global 4.0 ± 0.4 9.0 ± 1.5 3.76 ± 0.08 48 ± 3 57 ± 4 47 ± 2 52 ± 7N weighted by 1/sin(α)Angular Difference α of CMT and BX-GL Tracksha_glEntries 125Mean 3.974600RMS 5.307norm 5929 ±154.0500σ 3.76 ±0.0840030020010000 5 10 15 20 25 30 35 40 45 50α [°]Figure 5.21: Intermediate angle α between muon tracks reconstructed by the CMTand the global Borexino tracking. The entries have been scaled by 1/ sinα to accountfor the solid angle.1/sin α to account for the solid angle. The angular resolution has been found to beof the order of 4 ◦ . Results for all trackings are also presented in Tab. 5.6.In the next step the lateral resolution has been determined. Again, differentmethods were tried. Since the muons in consideration originate from cosmic radiation,it is assumed that all tracks point downwards. For a spatial comparison, the x-and y-coordinates of the track penetrating the z = 0 plane are used. They are calculatedfor both the CMT and Borexino tracking and their difference is histogrammed.The result for the ID tracking is depicted in Fig. 5.22. The distributions were fittedagain by a Gaussian with σ being a measure for the resolution. Results are presentedin Tab.5.6. This method does not take into account the inclination of the individualtracks. Especially for a large θ, uncertainties in the polar angle have a strong effecton ∆x and ∆y. Therefore, the impact parameter I has also been investigated toget an absolute measure. I is defined as the distance of the track to the Borexinocenter. It has been calculated for all trackings and the difference ∆I to the CMTtracking was again histogrammed and fitted by a Gaussian as shown in Fig. 5.23 forthe global tracking.The impact parameter itself only gives an absolute value for the distance if thetrack to the center of the SSS. Comparing the impact parameters from the different89
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Setup of a Drift Tube Muon Trackera
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AbstractIn this work the setup and
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3.5.5 Pattern Recognition . . . . .
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viii
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essential for vetoing these events.
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Chapter 2NeutrinosThe standard mode
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However, it did not yet deliver an
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Table 2.1: Neutrino oscillation par
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this assumption, the Standard Solar
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Figure 2.1: Neutrino flux at Earth
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asymmetry between neutrino and anti
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Figure 2.3: Expected ¯ν e energy
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Nb neutrino/fission-11010-2Neutrino
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108−dE/dx (MeV g −1 cm 2 )65432
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Figure 3.3: Setup of the muon track
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zyxModule b.0Module a.0Module b.1Mo
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Figure 3.6: Display of the slow con
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plastic scintillators. To avoid all
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N hitsHitmap Plane 06000h_hitmap0En
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Table 3.4: Data structure for calib
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TDC SpectrumN/[2 Channels]1000800H_
Page 46 and 47: Table 3.5: List of variables calcul
Page 48 and 49: with ∆⃗q = ⃗q n − ⃗q n−
Page 50 and 51: N [a.u.]∆ α (x)2200020000da0Entr
Page 52 and 53: d[mm]Reco Drift Distances201816H_RE
Page 54 and 55: N [a.u.]Real DataReal data0.06MCh1E
Page 56 and 57: χ 2N [a.u.]Probability103×10hc2p0
Page 58 and 59: N [a.u]Residuals20001800h0Entries 3
Page 60 and 61: Counts/(10 keV × day × 100 tons)1
Page 62 and 63: 4.1.3 Čerenkov LightČerenkov dete
Page 64 and 65: 4.2 The Borexino DetectorThe Borexi
Page 66 and 67: muons, is reduced by going deep und
Page 68 and 69: (typically below 50 cm), the locati
Page 70 and 71: 510Counts/(10 keV x day x 100 tons)
Page 72 and 73: counts/days*4 hitsDay (Red) and Nig
Page 74 and 75: eeSurvival probability for ν e, P0
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Page 78 and 79: P C P DSCINT C SCINT DySCINT BSCINT
Page 80 and 81: Figure 5.2: The CMT setup on top of
Page 82 and 83: Angular AcceptanceAngular Acceptanc
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Page 86 and 87: Table 5.3: Overview of all muon run
Page 88 and 89: N/dayAll Triggers vs Time12000h_tim
Page 90 and 91: Reco Hits in Scintillatory [mm]1000
Page 92 and 93: PMTPMTScintillatorPMTPMTFigure 5.16
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Page 98 and 99: Lateral x Resolution CMT - IDhlatx_
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Page 104 and 105: [m]z bxTrack Position in BX x=0 Pla
Page 106 and 107: N [arbitrary units]∆y all data200
Page 108 and 109: To determine the Borexino tracking
Page 110 and 111: Table A.1: Variables that can be se
Page 112 and 113: espectively. The channel numbers ar
Page 114 and 115: xyϕϕ ′βx ′µFigure C.2: Rela
Page 116 and 117: the z-coordinate z op,0 of the firs
Page 118 and 119: xyEvent: 470, Entry: 470, Time Tue
Page 120 and 121: [14] Ch. Kraus et al. Final Results
Page 122 and 123: [49] T. Araki et al. Experimental i
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Page 126: Jan Lenkeit und Björn Wonsak sowie
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Setup of a Drift Tube Muon Tracker and Calibration of Muon ...

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