Experiment Proposal - opera - Infn

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9 Detector options, developments and R&D 230 9.1 Other detector options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230 9.1.1 Bricks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230 9.1.2 Brick packing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231 9.1.3 Wall support structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233 9.1.4 Electronic trackers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233 9.1.5 Magnet design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 9.2 Further developments and R&D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .238 9.2.1 Development of liquid scintillator detectors . . . . . . . . . . . . . . . . . . . . . 238 9.2.2 Development of the Multi Track scanning approach . . . . . . . . . . . . . . . . . 239 9.2.3 Future test beam measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . 242 10 Installation of the detector 244 10.1 Space requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244 10.2 Detector installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 246 10.3 General installation schedule and commissioning . . . . . . . . . . . . . . . . . . . . . .248 11 <strong>Experiment</strong>al infrastructure 251 11.1 Infrastructure at Gran Sasso . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 11.2 Infrastructure for the emulsion readout facilities . . . . . . . . . . . . . . . . . . . . . . 253 12 The Collaboration 256 12.1 Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256 12.2 Contributions to the experiment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256 13 Cost of the experiment 258 13.1 Detector cost evaluation and running cost . . . . . . . . . . . . . . . . . . . . . . . . . . 258 13.2 Emulsion readout facilities and running cost . . . . . . . . . . . . . . . . . . . . . . . . 259 14 Conclusions and outlook 260 4
1 Introduction In this document we propose an experiment (OPERA) for the direct observation of ν τ appearance from ν µ ↔ ν τ oscillations in the CNGS long baseline beam [1] from the CERN SPS to the Gran Sasso Laboratory. OPERA aims at high sensitivity in the parameter region indicated by the deficit of atmospheric muon neutrinos and by its zenith angle dependence as observed by the Super-Kamiokande experiment. The experiment exploits nuclear emulsions as very high resolution tracking devices for the direct detection of the decay of the τ produced in the charged current (CC) interaction of the ν τ with the target. Preliminary ideas and designs of the experiment can be found in [2–5] and in the Progress Report presented to the Scientific Committees in 1999 [6]. The technique of nuclear emulsion has found a large scale application in the target of the CHORUS experiment [7] in which the automatic scanning of a large sample of events has first been applied. This technique can be further improved and lead to the much larger scale of the OPERA target. Its mass is made of lead plates, with emulsion films used as high precision trackers, unlike in CHORUS in which emulsions constitute the bulk of the target mass. The experiment design is based on the Emulsion Cloud Chamber (ECC) detector, a modular structure made of a sandwich of passive material plates interspaced with emulsion layers (Fig. 1). By assembling a large quantity of such modules, it is possible to conceive and realise a ∼ 2000 ton fine-grained vertex detector optimised for the study of ν τ appearance. Beam Emulsion Sheet (ES) Passive material plate Figure 1: Schematic structure of an Emulsion Cloud Chamber (ECC). This target is complemented by arrays of electronic trackers for the real time determination of the event position and by magnetised iron spectrometers for muon identification and for the reconstruction of their charge and momentum. 5
Page 1 and 2: CERN/SPSC 2000-028 SPSC/P318 LNGS P
Page 3 and 4: N. Bruski, S. Buontempo, F. Carbona
Page 5 and 6: Contents 1 Introduction 5 1.1 Physi
Page 7: 6.7.1 Multiple scattering analysis
Page 11 and 12: eactor experiments (KAMLAND [22], B
Page 13 and 14: difference being the nature of the
Page 15 and 16: The total energy of electrons and
Page 17 and 18: through the decay topology and its
Page 19 and 20: Figure 6: Simulated ν τ event wit
Page 21 and 22: particles above 10 MeV . One can se
Page 23 and 24: vertex position as predicted by the
Page 25 and 26: • stability and maintenance: no p
Page 27 and 28: Figure 11: Illustration of the vari
Page 29 and 30: Table 3: Expected numbers of τ and
Page 31 and 32: 3 The CNGS neutrino beam 3.1 The be
Page 33 and 34: per year of operation because the S
Page 35 and 36: ν µ at GS (p.o.t. GeV m 2 ) -1 10
Page 37 and 38: Figure 19: Generated (continuous li
Page 39 and 40: Emulsion Film + 56 (Lead + Emulsion
Page 41 and 42: The mechanical properties of the fi
Page 43 and 44: 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
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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
Page 83 and 84:
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
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
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Adjustable gain Channel 0 Sample &
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Trigger OUT IN Discri. Time Ref. PP
Page 103 and 104:
Super Module 1 Super Module 2 Super
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5 Analysis of the electronic detect
Page 107 and 108:
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
Page 113 and 114:
The worst case leading to the lowes
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electromagnetic showering events an
Page 117 and 118:
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
Page 125 and 126:
Figure 89: Muon momentum resolution
Page 127 and 128:
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
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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
Page 161 and 162:
Figure 120: Fraction of pions which
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#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
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The φ angle is expected to peak at
Page 187 and 188:
Table 19: Summary of the kinematica
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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
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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
Page 201 and 202:
7.6 Determination of the oscillatio
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measurement of the ratio between ν
Page 205 and 206:
Table 30: Neural network recognitio
Page 207 and 208:
(mrad) 0.04 0.02 0 -0.02 -0.04 10 2
Page 209 and 210:
Table 31: Radioactivity measurement
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ick. There is approximately a facto
Page 213 and 214:
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
Page 225 and 226:
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
Page 231 and 232:
Figure 168: Distributions of the ap
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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
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9 p.e. and 6.9 p.e. at a distance f
Page 245 and 246:
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,
Page 259 and 260:
on the size of these stations. A co
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Table 38: Expected contributions to
Page 263 and 264:
the developed emulsions and to stan
Page 265 and 266:
As the sensitivity is not limited b
Page 267 and 268:
[26] M. Apollonio et al., Phys. Let
Page 269:
[89] http : //tosca.web.cern.ch/T O
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