Experiment Proposal - opera - Infn

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8 Test measurements and results 8.1 Measurements on ECC brick components 8.1.1 Emulsion films In additions to the extensive studies of emulsion films from Fuji presented in Section 4.2.2, we also performed test measurements with industrial emulsion films produced by the Fomos company. 17 Bricks made with these films were exposed to muons at the CERN SPS. The films are made up of two 55 µm emulsion layers coated on both sides of a 180 µm plastic base. The emulsion gel has a dilution factor of three. The measured sensitivity is of 25 grains/100 µm for a minimum ionising particle. The fog density varies from 4 to 8 grains per 1000 µm 3 , depending on the development conditions. These features are compatible with the OPERA requirements. The beam test data allowed us to study, in particular, edge effects. The results are shown in Fig. 148 and indicate that the track finding efficiency stays rather constant near the film edge. A drop in the efficiency is measured for distances lower than ∼ 300 µm from the edge. We also determined the angular resolution of the emulsion films, by measuring the angles of penetrating muons in two emulsion films separated by 1 mm of lead. This is shown in Fig. 149. 8.1.2 Lead radioactivity measurements With the aim of identifying suitable materials for the brick lead plates, we performed extensive measurements of the radioactivity of commercial lead samples supplied by companies in Japan, USA and Europe. The α and β rays emissions were measured at the Nagoya University by using emulsion films and a gas proportional counter with 2π geometrical acceptance and surrounded by cosmic ray veto counters. Ameasurementoftheγ radioactivity was performed by high purity germanium detectors (HPGe) placed in the Modane Underground Laboratory (Fréjus tunnel). 18 A detailed GEANT 3.21 simulation of all the decay products of the 210 Pbradioactivity, namely the Pb → Bi → Pochain, was also performed. These tools had been successfully tested in the ultra-low radioactivity domain of the double beta decay NEMO experiment. Recognition of α particles in emulsion films is rather straightforward, since α’s leave short blacktrajectories in the emulsion layers. By counting these tracks one can estimate the emission level. Conversely, the estimate of the β radioactivity level is not trivial, due to Compton electrons produced from the natural γ ray background. Therefore, the reported emulsion measurements only refer to the α emission. In the case of gas proportional counter, insted, α and β can be separately measured by signal pulse height discrimination. The results of the measurements are summarised in Table 31. The α level as measured by a proportional counter well agrees with the measurement done with emulsion films. As the source of the emission 17 Fomos, 7 Leningradsky prospect, 125167, Moscow, Russia. 18 We thank F. Hubert and P. Hubert from the CENBG laboratory, France, and H. Ohsumi from the SAGA University for the lead radioactivity measurements. 202
(mrad) 0.04 0.02 0 -0.02 -0.04 10 2 10 3 segments up surface (microns) (mrad) 0.04 0.02 0 -0.02 -0.04 10 2 10 3 segments down surface (microns) 600 400 200 0 10 2 10 3 linked tracks (microns) Figure 148: Study of edge effect in the reconstruction of tracks with Fomos emulsion films. The top plots show the distortion of reconstructed segments in each of the two emulsion layers as a function of the distance from the edge. The bottom plot gives the number of reconstructed tracks (associated segments). 203
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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
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RPC layout 8.00 m 8.75 m Figure 58:
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formance, it is presently foreseen
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Figure 61: Drift plane arrangement
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Figure 63: Schematic view of a XPC
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Figure 64: Acceleration spectrum fo
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Figure 65: The OPERA detector shown
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Table 9: Number of electronic chann
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Adjustable gain Channel 0 Sample &
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Trigger OUT IN Discri. Time Ref. PP
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Super Module 1 Super Module 2 Super
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5 Analysis of the electronic detect
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Track segments on both the emulsion
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5.5 Brick finding efficiency The se
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Wall finding efficiency 1 0.95 0.9
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The worst case leading to the lowes
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electromagnetic showering events an
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Studies on the strategies have star
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which may enter in such a compariso
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Figure 84: The total brick finding
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Figure 86: Charge determination of
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Figure 89: Muon momentum resolution
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Figure 91: Muon momentum resolution
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Reconstructed Pion Energy N Analog
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Figure 98: The difference between r
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By using the above running modes of
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µm EXP.: DONUT 3039/01910 MOD.:ECC
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emulsion film plastic foils and edg
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200micron base 50micron emulsion la
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Figure 106: Tracking efficiency of
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a base track on film 2 a penetratin
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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
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
Page 187 and 188: Table 19: Summary of the kinematica
Page 189 and 190: known. Because of these uncertainti
Page 191 and 192: Table 21: Expected charm background
Page 193 and 194: π− e+ γ e- e+ e- γ π− Figur
Page 195 and 196: Table 24: Estimates of the rate of
Page 197 and 198: Table 27: Expected numbers of τ an
Page 199 and 200: Table 28: Sensitivity at the 90% CL
Page 201 and 202: 7.6 Determination of the oscillatio
Page 203 and 204: measurement of the ratio between ν
Page 205: Table 30: Neural network recognitio
Page 209 and 210: Table 31: Radioactivity measurement
Page 211 and 212: ick. There is approximately a facto
Page 213 and 214: Figure 152: A typical PMT response
Page 215 and 216: 1m π, µ 15 GeV/c mini-walls 1.6 m
Page 217 and 218: Electrons 1GeV/c 20mm Pb Number of
Page 219 and 220: tube. An Image Intensifier (II) by
Page 221 and 222: 1 0 0 l = 1 1 .8 m N, p.e. 1 0 1 0
Page 223 and 224: HPD’s pixels (Fig. 162). The cook
Page 225 and 226: A complete system has been designed
Page 227 and 228: The acquisition system (VA-DAQ) use
Page 229 and 230: The upstream tracker T 1-3 between
Page 231 and 232: Figure 168: Distributions of the ap
Page 233 and 234: Figure 169: Example of a large-angl
Page 235 and 236: multiple scattering, given the smal
Page 237 and 238: 9.1.3 Wall support structures An al
Page 239 and 240: Nevertheless, the possibility to us
Page 241 and 242: Figure 174: (a) 3D view of the spec
Page 243 and 244: 9 p.e. and 6.9 p.e. at a distance f
Page 245 and 246: Figure 176: Neutrino induced charm
Page 247 and 248: A test programme for emulsion brick
Page 249 and 250: The space requirements in the exper
Page 251 and 252: advance. The sets of scintillator s
Page 253 and 254: Task Name Start Finish Study of mai
Page 255 and 256: 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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