Experiment Proposal - opera - Infn

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Figure 50: HPD pulse height measurement. The first peak around bin 200 corresponds to the pedestal. The photoelectron peaks are clearly visible (up to the 7 th one). A global fit is applied using a Gaussian approximation for the individual peaks. The heights of the photoelectron peaks are fitted by a Poissonian. The mean number of photoelectron is around 3.5. 68
modate from 512 up to 5180 fibres. The high spatial resolution allows to resolve individual fibres. The readout time of 100 ms is limited by CCDs. Therefore, no trigger signal can be provided by the EBCCD. Several types of tubes with different CCDs were tested and results are encouraging. At relatively low cost per channel, the EBCCD can provide good gain uniformity, low cross talk and single photoelectron detection capability (see Section 8.2.3). 4.4.4 Readout electronics Studies have shown that an analog readout is preferred for the brick finding efficiency. A fast trigger has to be implemented in order to start the electronic channel readout and the data acquisition. In order to achieve triggering and charge measurement capabilities, the electronic signals from the photodetectors are amplified and split into two parts. One is sent to a fast discriminator and the other one to a slow shaping and charge measurement device. Depending on the strip and photodetector modularity, 16 to 64 channels are combined in a chip. In the baseline option we assume the combination of 64 channels, corresponding to the readout of one photodetector. The OR of the discriminators for each chip can trigger the charge sampling. The charge output of the electronic channels is multiplexed and sent to an ADC. It is also possible to send to the ADC’s only the signals of the channels above the discriminator threshold (selective readout). In this way, zero suppression is performed in the readout chip. This general scheme is common for the PMT and the HPD front end electronics. The changes mainly concern the first stage of preamplification because of the different polarities and amplitudes of the signal. A schematic layout of the readout electronics is shown in Fig. 51. The amplification of the first stage is defined by the sensitivity and the dynamical range to be covered by the whole electronic chain. The scintillator strip detectors aim at a sensitive range from 1 to 200 p.e. For PMT’s <strong>opera</strong>ted at a gain of 10 6 the range varies from 0.16 pC to 32 pC. In the case of HPD <strong>opera</strong>tion with a gain of 3500, the charge range varies from 0.6 fC to 120 fC. The discriminator thresholds must not exceed a value equivalent to 1 p.e. in order to keep a detector track efficiency higher than 97%. However, thresholds must be high enough to avoid triggering on electronic noise which would increase the counting rate and thus the acquisition dead time. The thresholds can be set to five times the RMS of the electronic noise. This was achieved by the MINOS collaboration using 64-pixel Hamamatsu PMT’s with a threshold at 0.3 p.e. This is more constraining for HPD’s, which have a relatively small gain and quite broad pedestal. In the following we describe three possible solutions under test for the front end electronics. A prototype chip based on the scheme described above has been designed with 16-signal channels and two test channels for electrical characterization. Each signal channel mixes a slow and a fast line to provide the autotrigger. The preamplifier, shared by these two lines, generates a voltage step in response to the signal of the photodetector. For PMT readout the preamplifier is replaced by a switch of adjustable gain. In 1999, a test chip was developed containing only a preamplifier with characteristics fulfilling the following requirements: gain of 3 mV/p.e, linearity over 300 p.e, ENCof450 electrons at 10 pF input capacitance and shaping time of 600 ns. 69
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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
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: photomultiplier to be tested diaphr
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 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
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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
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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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