Druck-Materie 20b.qxd - JUWEL - Forschungszentrum Jülich

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Experimental background, results and analysis (cont’d.) Study of Radiation Effects in Hydrogenous Moderator Materials at Low Temperatures (URAM-2 Project) E. Shabalin, V. Golikov, S. Kulikov, L. Golovanov, V. Melikhov, E. Kulagin, A. Belyakov, V. Ermilov, V. Konstantinov, A. Androsov, Yu. Borzunov 129 The JESSICA Experiment – Part I: Improvements of the JESSICA Experiment K. Nünighoff, H. Conrad, D. Filges, F. Goldenbaum, R.D. Neef, W. Ninaus, N. Paul, C. Pohl, H. Schaal, A. Smirnov, H. Stelzer, H. Tietze-Jänsch, W. Wohlmuther 155 A Cryogenic Moderator System for JESSICA, a Test Facility for Advanced Cold Moderators H. Stelzer, N. Bayer, H.-K. Hinssen, Th. Matzerath 161 Experimental Studies of Neutronic Characteristics of Hydrogen Moderators at Para-Rich Concentrations and Comparison with Calculations Y. Kiyanagi, H. Ogawa, M. Ooi and H. Iwasa 169 The JESSICA Experiment – Part II: Results from the JESSICA Experiment C. Pohl, H. Conrad, D. Filges, F. Goldenbaum, R.D. Neef, W. Ninaus, K. Nünighoff, N. Paul, H. Schaal, A. Smirnov, H. Stelzer, H. Tietze-Jänsch, W. Wohlmuther 175 Spontaneous Burp Phenomenon: Analysis of Experimental Data and Approach to Theoretical Interpretation E. Shabalin 183 Appendix Preliminary Evaluation of the Cold Neutron Cross Sections of CH4 - Hydrate J.R. Granada, V.H. Gillette, L. Torres, M.M. Sbaffoni, F. Cantargi 199 The Stern-Kirby-Durham approach to CH4-hydrate production H. Soltner 211 8
ABSTRACT ACoM - 6 6 th Meeting of the Collaboration on Advanced Cold Moderators <strong>Jülich</strong>, 11 – 13 September 2002 Evaluation of Scattering Laws and Cross Sections for Calculation of Production and Transport of Cold and Ultracold Neutrons W. Bernnat, J. Keinert, M. Mattes Institute for Nuclear Energy and Energy Systems University of Stuttgart Pfaffenwaldring 31, 70550 Stuttgart For the calculation of neutron spectra in cold and super thermal sources scattering laws for a variety of liquid and solid cyrogenic materials were evaluated and prepared for use in deterministic and Monte Carlo transport calculations. For moderator materials like liquid and solid H2O, liquid He, liquid D2O, liquid and solid H2 and D2, solid CH4 and structure materials such as Al, Bi, Pb, ZrHx, and graphite scattering law data and cross sections are available. The evaluated data were validated by comparison with measured cross sections and comparison of measured and calculated neutron spectra as far as available. Further applications are the calculation of production and transport and storing of ultra cold neutrons (UCN) in different UCN sources. The data structures of the evaluated data are prepared for the common SNtransport codes and the Monte Carlo Code MCNP. 1. INTRODUCTION For the optimisation of cold neutron sources transport and thermalisation calculations must be performed to get important parameters such as gain factors, heating rates and fluences for containers etc. For such transport and thermalisation calculations for all investigated moderators and structure materials realistic scattering laws must be available. There exist computer programs for the solution of the neutron transport equation based on the Monte Carlo method (MCNP-X [1]) or discrete ordinate SN-method (DORT/TORT [2]). The scattering law data and transport and thermalisation calculations must be validated by corresponding experiments by comparing of measured and calculated cross sections and neutron spectra. At IKE since many years scattering law data were derived and evaluated for a number of moderators and different phase states. The present data, developed at IKE are the following: • Liquid hydrogen as p-H2 and o-H2 at T = 14K and 20.38K • Liquid deuterium as o-D2 and p-D2 at T= 19K and 23.65K • Solid o-D2 at T = 5K, 10K, 13K and 17K • Solid p-H2 at T= 5K, 6K and 13K • Gaseous hydrogen as p-H2 and o-H2 at T = 20.38K and 25K • Gaseous deuterium as o-D2 and p-D2 at T = 23.65K • Liquid helium as 4 He at T = 1K (UCN-production) • Bismuth at T = 77K and 293.6K • Beryllium at T = 2.5K and 25K • Aluminium at T = 20K, 100K and 293.6K • Lead at T = 293.6K • Heavy Water as D(D2O), O(D2O) + all other interference terms at T = 293.6K 9
Page 1 and 2: ACoM - 6 6th 6 International Worksh
Page 3 and 4: Forschungszentrum Jülich GmbH Inst
Page 5: Preface These are the Proceedings o
Page 8 and 9: List of participants, cont’d. Kü
Page 10 and 11: Pepe M. 43 Petriw S. 43 Picton D.J.
Page 14 and 15: • Light water ice as H(H2O) at T
Page 16 and 17: In Table 2 a survey is given about
Page 18 and 19: sigma-T in barns/molecule Figure 4.
Page 20 and 21: 2.3 Liquid water Compared to the so
Page 22 and 23: presented. The corresponding experi
Page 24 and 25: 3.2 Gaseous hydrogen and deuterium
Page 26 and 27: Rho(Omega) normalised 160 140 120 1
Page 28 and 29: elatively free and can also suffer
Page 30 and 31: Figure 16. Heat Capacity for Solid
Page 32 and 33: o-D2 and p-H2 at 5K for an ucn ener
Page 34 and 35: Figure 22. UCN Upscattering Rates i
Page 36 and 37: ho(omega) normalised 40 35 30 25 20
Page 38 and 39: derived from Walker [52]. The neutr
Page 40 and 41: Since there is only a small gain of
Page 42 and 43: 7. CALCULATION OF SCATTERING LAW DA
Page 44 and 45: For the validation of these data se
Page 46 and 47: [36] Nielsen, M.: Phonons in Solid
Page 48 and 49: 2. THE CASE OF MOLECULAR SOLIDS An
Page 50 and 51: γ r ( 0) ≅ 2 2 2 T erf e ( ) / 2
Page 52 and 53: 4. PRELIMINARY APPLICATION Solid Me
Page 54 and 55: [5] Meeting on Moderator Concepts a
Page 56 and 57: state. Conversely, the monatomic hy
Page 58 and 59: Note that the equilibrium trihydrog
Page 60 and 61: para hydrogen system under irradiat
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[12] T. E. Fessler and J. W. Blue,
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tion of neutron intensities, partic
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varied between calculations but the
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5. THE OPTIMISATION OF MULTIPLY GRO
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Figure 7. A comparison of time dist
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4.8 cm hydrogen slab in front of a
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ACoM - 6 6 th Meeting of the Collab
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the moderator is annealed every 12
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The method requires two additional
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ABSTRACT ACoM - 6 6 th Meeting of t
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Heat transfer processes across phas
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3. TWO-PHASE FLOW PATTERN IN THE MO
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continuous phase dominating, and a
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Also the velocity pattern has chang
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Figure 8. Methane pellets concentra
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ACoM - 6 6 th Meeting of the Collab
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sample volume and the nominal densi
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The results presented in this paper
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Table 10. Summary of energy transfe
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2. EXPERIMENTAL Methane hydrate was
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Figure 4. Energy levels of methane
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102
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phase transitions from phase II to
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After melting phase I in the cryost
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4. SOLID PHASES OF MESITYLENE-D0 AN
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G(ν) [a.u.] 8 6 4 2 Phase II Phase
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112
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A not quite as perfect cold spectru
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2.2 Inelastic neutron scattering Th
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Figure 4. Inelastic spectra at the
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3.2 Moderator performance The resul
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122
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Figure 2. The methane pelletizer, m
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Figure 5. The cryogenic hopper fill
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128
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ture
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The charging device scheme could be
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Table 1. Data of irradiation of met
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5. METHODS OF PROCESSING OF RAW EXP
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of radicals, that is, before a burp
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6.2 Condition for thermally stimula
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Table 4. Estimated values of an ene
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• Nine spontaneous burps were obs
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APPENDIX Some useful relations and
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APPENDIX. Graphs of burps. 148
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150
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152
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154
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2. EXPERIMENTAL SETUP Fig. 1 will g
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All these parameters are kept const
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4. CONCLUSIONS We demonstrated that
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JESSICA (Juelich Experimental Spall
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The moderator system consists of th
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to change the temperatures and to p
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168
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supplied from the high pressure bom
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10 9 10 8 10 7 10 6 Para35%[Experim
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174
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2. TIME OF FLIGHT SPECTRA AND ENERG
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When applying this transformation t
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data were analyzed in more detail.
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182
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First of all, we should conclude th
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The equation (a) may also describe
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Even at h=0.01 mm which is too smal
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model and some consequences of its
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methane and 0.7-1.5% for water ice
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case: the sample of infinite size.
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196
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198
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200
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202
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204
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206
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208
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210
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Phase Diagram of the CH4-H20 system
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Reaction Chamber for Hydrate Produc
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Analysis: X-ray diffraction pattern
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Comparison with non-hydrate forming
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Mechanical Tests: Apparatus 220
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Morphology of Indium Jacket 222
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Schriften des Forschungszentrums J
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Schriften des Forschungszentrums J
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