Experiment Proposal - opera - Infn

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The whole event reconstruction is based on the channel time correlation. This depends on the accuracy of the electronic channels time-stamps. A time resolution of 5 ns corresponding to the total electronic time jitter has been retained. A common time reference with respect to the Universe Time Coordinated (UTC) is provided by a Global Positioning System (GPS). The beam bursts are recorded with another GPS at CERN to establish the offline correlation between the recorded events and the beam cycles. The different detector elements need a slow control system to monitor parameters affecting the detector performance. Some of them are listed below • scintillator detectors: temperature, high voltages, low voltages and currents of photodetectors; • RPC’s: gas flow and mixture, temperature, atmospheric pressure, high voltages, low voltages and currents; • drift tubes: gas flow and mixture, temperature, atmospheric pressure, high voltages, low voltages and currents; • magnet: temperatures, power supplies and cooling, water control of the cooling system, magnetic field, voltages and currents. PMT Front End Electronics Readout Interface Event Builder / Trigger Processor Farm Readout Interface Units Acq CPU VME crate x19 Front End Units Serial Link PPS Acq CPU 64 Channels Proc 0 Proc 1 Proc 2 Proc 3 Switch Ethernet 1Gbit Acquisition Network Proc n VME crate x19 Discriminator Output Super Module 1 Serial Link (GPS time reference) Time Reference From Super Module 2 From Super Module 3 GPS Receiver User Interface External antenna Optical Fiber Acquisition - Database Storage Control - Monitoring Ethernet 100Mbit - Control Network Figure 66: Overview of the data acquisition system. 92
Table 9: Number of electronic channels in each main detector. Electronic detector Nb. of planes Nb. of channels/plane Total Target Trackers 3 × 48 512 73728 Spectrometer RPC’s 3 × 22 560 36960 Spectrometer drift tubes 3 × 6 768 13824 Spectrometer XPC’s 3 × 2 790 4740 4.7.2 Data flow To evaluate the expected data flow from the electronic detectors, we have considered a suitable safety factor, accounting for the largest possible number of electronic channels. A maximum counting rate induced by natural radioactivity of about 10 Hz per electronic channel is assumed. Detector and electronic noise have to be added. Using the Hamamatsu 64-channel PMT with a threshold corresponding to 1/3 photoelectron, a noise frequency lower than 5 Hz has been measured, mainly coming from the photocathode thermoemission. The use of HPD’s for the scintillator readout could increase the electronic noise by at least one order of magnitude as compared to the PMT for the same threshold. Taking into account possible noisy elements a mean electronic noise of the order of 50 Hz is considered for the scintillator strips of the target. For RPC’s the noise is assumed to be of the same order. The drift tubes of the Precision Trackers require an external time reference. The TDC common STOP could be provided (within a time shorter than 512 ns) by the RPC’s associated with the spectrometer. Thus, since the Precision Trackers do not participate in the trigger, the electronic noise of this detector does not significantly disturb the acquisition system. For the data flow evaluation an electronic noise of 50 Hz has also been assumed. Table 9 gives the number of electronic channels for the three detectors. For each detected hit, at most 12 byte are stored (channel address, signal and time). The total rate amounts to about 90 Mbyte/s. If the final electronic noise rate would be significantly higher, fast time correlations between X and Y channels could be performed before signal digitization. These correlations could be used as external signal to trigger the frond end readout cards and thus, reduce the noise. In any case, the acquisition system must be able to support at least three times the above referred to rate. 4.7.3 Front end electronics This part of the electronics is the only one which has to be adapted to each specific detector. In this Section, we describe in particular the scintillator readout. The front end unit includes the following components: the front end chip, the ADC’s, the local trigger, the serial link controller and the programmable chip. Its schematic diagram is shown in Fig. 67. One can make use of boxes close to the photodetector from where the data flow is transmitted by a serial link. The discriminator signal is also sent to the readout interface. Other signals (external trigger, 93
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CERN/SPSC 2000-028 SPSC/P318 LNGS P
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N. Bruski, S. Buontempo, F. Carbona
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Contents 1 Introduction 5 1.1 Physi
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6.7.1 Multiple scattering analysis
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1 Introduction In this document we
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eactor experiments (KAMLAND [22], B
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difference being the nature of the
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The total energy of electrons and
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through the decay topology and its
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Figure 6: Simulated ν τ event wit
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particles above 10 MeV . One can se
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vertex position as predicted by the
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• stability and maintenance: no p
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Figure 11: Illustration of the vari
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Table 3: Expected numbers of τ and
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3 The CNGS neutrino beam 3.1 The be
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per year of operation because the S
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ν µ at GS (p.o.t. GeV m 2 ) -1 10
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Figure 19: Generated (continuous li
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Emulsion Film + 56 (Lead + Emulsion
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The mechanical properties of the fi
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Figure 24: Film thickness distribut
Page 45 and 46: contact at different temperature an
Page 47 and 48: Figure 27: Photograph of a minimum
Page 49 and 50: entry : 85 RMS: 0.060 15 10 5 0 0 d
Page 51 and 52: [micron] 2 1 0 -1 -2 [micron] 2 1 0
Page 53 and 54: een searching for old emulsion plat
Page 55 and 56: Figure 33: Thickness distribution f
Page 57 and 58: Figure 35: RMS distribution of 472
Page 59 and 60: Figure 37: Wall support structure.
Page 61 and 62: ensures a well defined brick positi
Page 63 and 64: Figure 41: Detail of the brick mani
Page 65 and 66: The strips are 6.7 m long, 2.6 cm w
Page 67 and 68: the effective maximal length (for p
Page 69 and 70: Table 7: Characteristics of the 64-
Page 71 and 72: photomultiplier to be tested diaphr
Page 73 and 74: modate from 512 up to 5180 fibres.
Page 75 and 76: The fast shaper has a high gain in
Page 77 and 78: The Ethernet capable device provide
Page 79 and 80: R&D already performed by the MINOS
Page 81 and 82: Figure 54: Isometric view of the di
Page 83 and 84: Figure 56: Magnetic field distribut
Page 85 and 86: RPC layout 8.00 m 8.75 m Figure 58:
Page 87 and 88: formance, it is presently foreseen
Page 89 and 90: Figure 61: Drift plane arrangement
Page 91 and 92: Figure 63: Schematic view of a XPC
Page 93 and 94: Figure 64: Acceleration spectrum fo
Page 95: Figure 65: The OPERA detector shown
Page 99 and 100: Adjustable gain Channel 0 Sample &
Page 101 and 102: Trigger OUT IN Discri. Time Ref. PP
Page 103 and 104: Super Module 1 Super Module 2 Super
Page 105 and 106: 5 Analysis of the electronic detect
Page 107 and 108: Track segments on both the emulsion
Page 109 and 110: 5.5 Brick finding efficiency The se
Page 111 and 112: Wall finding efficiency 1 0.95 0.9
Page 113 and 114: The worst case leading to the lowes
Page 115 and 116: electromagnetic showering events an
Page 117 and 118: Studies on the strategies have star
Page 119 and 120: which may enter in such a compariso
Page 121 and 122: Figure 84: The total brick finding
Page 123 and 124: Figure 86: Charge determination of
Page 125 and 126: Figure 89: Muon momentum resolution
Page 127 and 128: Figure 91: Muon momentum resolution
Page 129 and 130: Reconstructed Pion Energy N Analog
Page 131 and 132: Figure 98: The difference between r
Page 133 and 134: By using the above running modes of
Page 135 and 136: µm EXP.: DONUT 3039/01910 MOD.:ECC
Page 137 and 138: emulsion film plastic foils and edg
Page 139 and 140: 200micron base 50micron emulsion la
Page 141 and 142: Figure 106: Tracking efficiency of
Page 143 and 144: a base track on film 2 a penetratin
Page 145 and 146: Long decays, defined as a decay top
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more than 60 views/s recognising al
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Table 12: Basic numbers used to des
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an area that one S-UTS can process
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unit cell L=1300micron Pb plate ( 1
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We recall that the intrinsic positi
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Figure 116: The top histograms show
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The error on θ S due to both the s
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Figure 120: Fraction of pions which
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#1 #2 #3 #4 #5 γ γ ∆θ 4= |θ 5
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Figure 124: Energy resolution for e
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Figure 126: Efficiency for γ’s t
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7 Physics performance 7.1 Electron
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7.2 Muon identification efficiency
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Table 13: Muon identification effic
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Table 14: Brick finding efficiency
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The second result is obtained from
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Figure 134: Brick-to-brick connecti
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Figure 136: Distribution of τ deca
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For long decays the overall efficie
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The φ angle is expected to peak at
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Table 19: Summary of the kinematica
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known. Because of these uncertainti
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Table 21: Expected charm background
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π− e+ γ e- e+ e- γ π− Figur
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Table 24: Estimates of the rate of
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Table 27: Expected numbers of τ an
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Table 28: Sensitivity at the 90% CL
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7.6 Determination of the oscillatio
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measurement of the ratio between ν
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Table 30: Neural network recognitio
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(mrad) 0.04 0.02 0 -0.02 -0.04 10 2
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Table 31: Radioactivity measurement
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ick. There is approximately a facto
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Figure 152: A typical PMT response
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1m π, µ 15 GeV/c mini-walls 1.6 m
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Electrons 1GeV/c 20mm Pb Number of
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tube. An Image Intensifier (II) by
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1 0 0 l = 1 1 .8 m N, p.e. 1 0 1 0
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HPD’s pixels (Fig. 162). The cook
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A complete system has been designed
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The acquisition system (VA-DAQ) use
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The upstream tracker T 1-3 between
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Figure 168: Distributions of the ap
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Figure 169: Example of a large-angl
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multiple scattering, given the smal
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9.1.3 Wall support structures An al
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Nevertheless, the possibility to us
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Figure 174: (a) 3D view of the spec
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9 p.e. and 6.9 p.e. at a distance f
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Figure 176: Neutrino induced charm
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A test programme for emulsion brick
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The space requirements in the exper
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advance. The sets of scintillator s
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Task Name Start Finish Study of mai
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11 Experimental infrastructure 11.1
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After the exposure to cosmic rays,
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on the size of these stations. A co
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Table 38: Expected contributions to
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the developed emulsions and to stan
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As the sensitivity is not limited b
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[26] M. Apollonio et al., Phys. Let
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[89] http : //tosca.web.cern.ch/T O
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