NeuLAND - FAIR

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PNPI St. Petersburg: G.D. Alkhazov, V.A. Andreev, A.A. Fetisov, V.L. Golovtsov, E.A. Ivanov, A.G. Krivshich, L.N. Uvarov, V.V. Vikhrov, S.S. Volkov, A.A. Zhdanov Chalmers Univ. of Technology: A. Heinz 98 Sweden
B. Neutron MRPC Results in Details The final <strong>NeuLAND</strong> design is based on a fully active detector of organic scintillator material. However, in the past also an alternative scheme using passive converters and a multigap resistive plate chamber (MRPC) based detector had been investigated in detail, including the construction and test of a fully operational 2 m long prototype. The scintillator-based design shows significantly better performance than the MRPC option, therefore it is adopted for the technical design of <strong>NeuLAND</strong>. The present appendix summarizes the main results of the MRPC studies for reference. B.1. Principle of Operation of an MRPC-Based Neutron Detector with a Thick Iron Converter The principle of operation for an MRPC-based neutron detector is derived from the existing Large Area Neutron Detector (LAND) [Bla-92] at GSI, which has a face size of 2×2 m 2 . LAND converts neutrons into charged particles in 5 mm thick iron plates, and subsequently detects the charged particles in plastic scintillators of the same thickness. With LAND, typical detection efficiencies above 90% have been reached for 400 MeV neutrons [Bor-03], see sections 4.2 and 4.1.2 for details. Detectors that are similar to LAND have been used elsewhere, e.g. at Forschungszentrum Jülich [Roz-05] and with the MONA detector at Michigan State University [Bau-05]. It should be noted, however, that in the MONA case the converter is presently not used. For the MRPC-based neutron-detector prototype, a setup similar to LAND is used, but the scintillator is replaced with an MRPC. As converter material, stainless steel is selected for practical reasons. In an MRPC, a charged particle passing through a gas volume causes ionization. Owing to the electrical field strength of ≈100 mV/cm, an avalanche is caused by this ionization. The mirror charge of the avalanche on a readout electrode is used as signal. MRPC’s are well-known for their excellent time resolution, as low as σt = 20 ps for special configurations [An-08]. They are only weakly sensitive to γ-rays [Ali-07], eliminating an important source of background. In the literature there are reports of successful operation of large-scale MRPC structures on the scale of 1.5 m [Bla-02, Abb-09] for minimum ionizing particles. However, besides the neutron MRPC option presented here, to date no high-energy neutron detector involving MRPCs has been developed. 99
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FAIR/NUSTAR/R 3 B/TDR NeuLAND Techn
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Germany EMMI and FIAS: Enrico Fiori
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INR Moscow: Alexander Botvina Russi
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Contents Executive Summary 11 1. In
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B.7. MRPC Solution using Glass as C
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Apart from the excellent energy res
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processes in the universe, such as
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decaying into 24 O plus 4 neutrons
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2. Physics Scenarios: Requirements
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e studied at R 3 B at FAIR include
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all theoretical calculations predic
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at the surface of the nucleus. The
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the evolution of fission channels (
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3. Summary of NeuLAND Prototype Res
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counts 70 60 50 40 30 20 10 0 15 15
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Figure 3.4.: Shown is the time reso
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4. Monte Carlo Simulations Within t
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normalized counts normalized counts
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GEANT3 interface. Here, we compare
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Counts 1000 900 800 700 600 500 400
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counts 5 10 4 10 3 10 2 10 10 LAND
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incident neutron fully active detec
Page 47 and 48: investigated. Three values for the
Page 49 and 50: spectrum, absorption length, refrac
Page 51 and 52: Counts 600 500 400 300 200 100 with
Page 53 and 54: Since, as discussed above, several
Page 55 and 56: events 800 600 400 200 0 0 200 400
Page 57 and 58: clusters N 100 50 0 0 500 1000 1500
Page 59 and 60: In the following section we discuss
Page 61 and 62: events 15000 10000 5000 input outpu
Page 63 and 64: events 2000 1500 1000 500 σ = 15 k
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Page 71 and 72: Figure 5.6.: Detector frame with fi
Page 73 and 74: 5.4. Peripheral Systems 5.4.1. Read
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Page 83 and 84: Figure 8.3.: ToF distribution in 10
Page 85: Figure 8.4.: Event display for seve
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Page 96 and 97: 96 2. Sample Tests Random samples o
Page 100 and 101: HV 1.$ mm 2$ mm 0+$1-2)-2'.%/ 5%4'.
Page 102 and 103: Beamline Be exit window P 6 P 3 P 4
Page 104 and 105: B.3. Design Issues Addressed with 4
Page 106 and 107: Time [ns] Counts 41 40 39 2200 2000
Page 108 and 109: Efficiency 100 80 60 40 20 0 7.5 8
Page 110 and 111: 200 AMeV, Erel = 100 keV emitted %
Page 112 and 113: B.7. MRPC Solution using Glass as C
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Page 116 and 117: [Bot-04] S. Botvina andI.N. Mishust
Page 118 and 119: [Lip-03] C. Lippmann, PhD Thesis, U
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NeuLAND - FAIR

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