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

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N [a.u.]Real DataReal data0.06MCh1Entries 182769Mean 3.433RMS 1.83N [a.u.]Real Data0.12Real DataMCh3Entries 182769Mean 0.3951RMS 0.1640.10.050.040.080.030.060.020.040.010.0200 1 2 3 4 5 6ϕ [rad]00 0.2 0.4 0.6 0.8 1 1.2 1.4θ [rad]Figure 3.14: Comparison of reconstructed and Monte Carlo (MC) cosmic data. Theleft figure shows the azimuth angular distribution. The two distinct peaks arise formthe non symmetrical setup of the trigger scintillators, the difference in their heightfrom a parallel shift. The right picture shows the polar distribution. The data isin good agreement with the simulation. However, small discrepancies remain, arisingfrom small uncertainties in the exact trigger positions and the fit.fulfill the following condition:r(θ) =θ∫dϑ sin ϑ cos 2 ϑ0π∫20dϑ sin ϑ cos 2 ϑ= 1 − cos 3 θ.Therefore θ is given byθ = cos −1 3√ 1 − r.Once all parameters have been generated, it is checked whether the resultingtrack would go through at least one scintillator layer above and below the detector.If this is the case, the event is considered triggered. Now the number of hit tubesis calculated. The event is saved to a tree with the same data structure as TData,extended by the simulated coordinates of the track.Fig. 3.14 shows a comparison of both the azimuth and zenith angular distributionsof reconstructed real data with the Monte Carlo simulation. In general, thedata is in good agreement with the simulation. However, some small discrepanciescan be noted. In the azimuth distribution, two distinct peaks can be observed.They result mainly from the trigger scintillator setup. Whereas the scintillators werecrossed on top of the detector, they were placed parallel underneath, thus leavinga preferred direction for tracks along the y axis. This corresponds to values of ϕaround π and 3π 2. This alone still does not explain why one of the peaks is slightlylarger than the other. The relative heights of the peaks are very sensitive to theexact positions of the trigger scintillators. When the upper scintillators get shifted46
∆ p(α) y-z-plane∆ p21.510.5h_shift_0Entries 4093Mean 4.098Mean y -0.25RMS 1.537RMS y 1.513∆ y -0.02541∆ z 1.6830-0.5-1-1.5-20 1 2 3 4 5 6αFigure 3.15: The difference ∆p from the single module reconstruction in the y − zplane in dependence of α. The red line is a fit to Eq. 3.22 with ξ = y and ζ = z. Thedata was obtained performing only the initial calibration. Hence the data shows stillsome uncertainties. However, a systematic shift, mainly in z, can already be observed.This is expected, because the mechanical alignment could be done with a much higherprecision in x using a plumb.in y, muons coming from the direction the scintillator was shifted to are favoredwith respect to tracks in the reverse direction. The same is true for shifts in x. Thisalso explains the small disagreements between the Monte Carlo simulation and thereal data: Unfortunately, the scintillator positions have not been measured preciselyenough. The uncertainties in their position accounts for the offset between the dataand the simulation.3.8.2 Cosmic DataCosmic muons have been tracked and reconstructed with the CMT in the laboratoryin Hamburg. Fig. 3.13 shows the event display of an event before and afterreconstruction. The results presented in this chapter are based on a data samplewith 284605 events taken on March 4 th 2009. The data has been processed as describedin the previous section. First, a reconstruction for every single module wasperformed. Based on this data an angular alignment could be done. Fig. 3.11 showsthe angular differences exemplary for the two modules in the x − z-plane. Withoutany prior alignment, the angular differences are quite small which shows the precisemechanical angular alignment of the modules.In the next step, a possible shift of the modules was investigated. Fig. 3.15shows ∆p(α) for the two modules in the y − z-plane. A fit to Eq. 3.22 as describedin Section 3.6.1 shows a negligible offset in the horizontal direction. However, anoffset of ∆z = 1.683 mm is found. This does not surprise, since the modules werealigned merely using a level and a plumb. This method is fairly precise for theangular as well as the horizontal alignment. The vertical position was measuredwith a simple folding rule, hence higher uncertainties are expected.The module positions have been corrected as described in Section 3.6 and the47
Page 1 and 2:
Setup of a Drift Tube Muon Trackera
Page 3: AbstractIn this work the setup and
Page 6 and 7: 3.5.5 Pattern Recognition . . . . .
Page 8 and 9: viii
Page 10 and 11: essential for vetoing these events.
Page 13 and 14: Chapter 2NeutrinosThe standard mode
Page 15 and 16: However, it did not yet deliver an
Page 17 and 18: Table 2.1: Neutrino oscillation par
Page 19 and 20: this assumption, the Standard Solar
Page 21 and 22: Figure 2.1: Neutrino flux at Earth
Page 23 and 24: asymmetry between neutrino and anti
Page 25 and 26: Figure 2.3: Expected ¯ν e energy
Page 27: Nb neutrino/fission-11010-2Neutrino
Page 30 and 31: 108−dE/dx (MeV g −1 cm 2 )65432
Page 32 and 33: Figure 3.3: Setup of the muon track
Page 34 and 35: zyxModule b.0Module a.0Module b.1Mo
Page 36 and 37: Figure 3.6: Display of the slow con
Page 38 and 39: plastic scintillators. To avoid all
Page 40 and 41: N hitsHitmap Plane 06000h_hitmap0En
Page 42 and 43: Table 3.4: Data structure for calib
Page 44 and 45: 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 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
Page 76 and 77: the CMT to the Borexino tracking, t
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
Page 84 and 85: Comparison nhits=3 vs nhits=4N [a.u
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
Page 94 and 95: the CMT data file and the Borexino
Page 96 and 97: Zenith Angle CMT and BX-GL Tracks h
Page 98 and 99: Lateral x Resolution CMT - IDhlatx_
Page 100 and 101: Distance d between CMT and BX-GL Tr
Page 102 and 103: Angular difference αN [arbitrary u
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
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xyEvent: 470, Entry: 470, Time Tue
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[14] Ch. Kraus et al. Final Results
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[49] T. Araki et al. Experimental i
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116
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Jan Lenkeit und Björn Wonsak sowie
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