Experiment Proposal - opera - Infn

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6.2.2 Brick disassembly and emulsion film development After the cosmic-ray exposure the ECC bricks are disassembled into films and lead plates. The brick number, the event number, the stacking order of the emulsion films and of the lead plates are recorded. The lead plate thickness is an important parameter to be known when candidate events are to be precisely analysed. Lead plates are stored for measurementonlaterrequest. Prior to the development fiducial marks as well as brick, event and film number are printed on the films by a photographic method. The marks are needed for global correction of the film deformations. The emulsion films are then developed by semi-automatic machines. These can process ∼ 600 films per day, equivalent to 10 bricks. The realisation of such machines is not expected to be critical, because of the experience with similar devices <strong>opera</strong>ting daily in modern hospitals for X-ray film development. The development procedure can be performed at the surface laboratory if the time interval between the brick disassemby and the film development is shorter than about one hour, as expected for the machines we plan to use. This limitation arises to avoid recording of isolated tracks during the disassembly phase. This is crucial for the electron cascade shower analysis in the ECC brick. One needs, in fact, to suppress the density of isolated track down to the level of ∼ 1/mm 2 . 6.2.3 Packing emulsion films for scanning For efficient track recognition by the Track Selector system, the thickness of each emulsion layer must be large compared to the focal depth of the microscope. For this reason, the emulsion layer is expanded at the development to recover its initial thickness. Materials like Glycerine are infiltrated into the space previously occupied by the AgBr grains. Each developed film is then packed in a transparent plastic foil as shown schematically in Fig. 102. This foil stabilises the emulsion layer thickness and protects the swelled soft emulsion surface during the scanning <strong>opera</strong>tions. All packed emulsion films of a brick are then mounted in a cassette. At the scanning stage, each film is picked up from the cassette automatically and tied onto the microscope stage with vacuum sucking. The plastic foil must have the same refraction index as the emulsion gel in order to preserve the optical visibility. Packed films are then distributed to the film readout facilities. This transportation can be performed daily and must proceed smoothly, in order to keep the feedback from the readout as prompt as possible. This is required if a decay candidate is identified and the full event analysis by scanning additional bricks has to be performed. 6.3 The analysis stream The emulsion film analysis stream is subdivided into three phases, as illustrated in Fig. 103. These are the vertex location, the decay candidate selection and the full event analysis. Vertex location and decay candidate selection imply a rather time-intensive work and must be designed and scheduled to be performed quasi-online. Micro tracks on each side of the emulsion film are read out independenlty by the Track Selector. By connecting micro tracks on both sides of the plastic base, one obtains an angular resolution of about 132
emulsion film plastic foils and edge support to pack emulsion film glass table of a microscope stage channel for vacuum sucking Figure 102: A schematic picture of an emulsion film packed with a plastic foil. All edges of the emulsion film are surrounded by a plastic support used for the vacuum sucking onto the microscope stage. VWDUW 9HUWH[ /RFDWLRQ )LUVW (&& EULFN *HQHUDO 6FDQ SLFN XS HYHQW UHODWHG WUDFNV RQ 66 9HUWH[ /RFDWLRQ 1H[W (&& EULFN 6FDQ %DFN VFDQ EDFN E\ R[[ DOJRULWKP JHQHUDO VFDQ WR WUDFH XS FDVFDGHG HOHFWURQV 9HUWH[ &RQILUPDWLRQ FRQILUP QHXWULQR LQWHUDFWLRQ YHUWH[ &RQILUPHG " QR FRQWLQXH " \HV 'HFD\ &DQGLGDWH 6HOHFWLRQ &RQILUPHG " \HV QR 'HFD\ &DQGLGDWH 6HOHFWLRQ ORQJ VKRUW GHFD\ WRSRORJLHV GHFD\ 37 FXW UHTXHVW DGGLWLRQDO (&& EULFNV LI QHHGHG 'HFD\ " \HV )XOO 'DWD 7DNLQJ 'HFD\ " \HV )XOO 'DWD 7DNLQJ Figure 103: The flow diagram of the ECC brick analysis is schematically illustrated. A detailed description is given in the text. 133
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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
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contact at different temperature an
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Figure 27: Photograph of a minimum
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entry : 85 RMS: 0.060 15 10 5 0 0 d
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[micron] 2 1 0 -1 -2 [micron] 2 1 0
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een searching for old emulsion plat
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Figure 33: Thickness distribution f
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Figure 35: RMS distribution of 472
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Figure 37: Wall support structure.
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ensures a well defined brick positi
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Figure 41: Detail of the brick mani
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The strips are 6.7 m long, 2.6 cm w
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the effective maximal length (for p
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Table 7: Characteristics of the 64-
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photomultiplier to be tested diaphr
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modate from 512 up to 5180 fibres.
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The fast shaper has a high gain in
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The Ethernet capable device provide
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R&D already performed by the MINOS
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Figure 54: Isometric view of the di
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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 and 96: Figure 65: The OPERA detector shown
Page 97 and 98: Table 9: Number of electronic chann
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: µm EXP.: DONUT 3039/01910 MOD.:ECC
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
Page 147 and 148: more than 60 views/s recognising al
Page 149 and 150: Table 12: Basic numbers used to des
Page 151 and 152: an area that one S-UTS can process
Page 153 and 154: unit cell L=1300micron Pb plate ( 1
Page 155 and 156: We recall that the intrinsic positi
Page 157 and 158: Figure 116: The top histograms show
Page 159 and 160: The error on θ S due to both the s
Page 161 and 162: Figure 120: Fraction of pions which
Page 163 and 164: #1 #2 #3 #4 #5 γ γ ∆θ 4= |θ 5
Page 165 and 166: Figure 124: Energy resolution for e
Page 167 and 168: Figure 126: Efficiency for γ’s t
Page 169 and 170: 7 Physics performance 7.1 Electron
Page 171 and 172: 7.2 Muon identification efficiency
Page 173 and 174: Table 13: Muon identification effic
Page 175 and 176: Table 14: Brick finding efficiency
Page 177 and 178: The second result is obtained from
Page 179 and 180: Figure 134: Brick-to-brick connecti
Page 181 and 182: Figure 136: Distribution of τ deca
Page 183 and 184: For long decays the overall efficie
Page 185 and 186: 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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