Dissertation Shielding Studies for the CERN Super-Proton-Synchrotron at Experimental Point 5 ausgeführt zum Zwecke der Erlangung des akademischen Grades Doktor der technischen Wissenschaften unter der Leitung von Univ. Prof. Dr. Ewald Schachinger Institut für Theoretische Physik – TU Graz und CERN-THESIS-2004-038 21/08/2004 Dr. Graham R. Stevenson CERN, Schweiz Eingereicht an der Technischen Universität Graz Technisch-Naturwissenschaftliche Fakultät von Dipl. Ing. Mario J. Mueller Matrikelnummer 9030360 Sackstrasse 19/1/4 A-8010 Graz Genéve, August 2004 Meinem Grossvater / To my grandfather Johann Konrad 30.10.1923 - 27.02.2003 Acknowledgements As one can assume it needs many people for the successful completion of a doctoral thesis – it is time to thank: First of all I would like to thank Dr. Graham R. Stevenson for giving me the opportunity to carry out this thesis at CERN. This work would not have been possible without his assistance and continuous support. I am indebted to my supervisor and mentor Prof. Dr. Ewald Schachinger who supported and supervised my work far beyond the supervisor's duties. Special thanks to Dr. Doris Forkel-Wirth and Dr. Hans-Georg Menzel, for all the motivating support they had given me. I would also like to thank Dr. Waldemar Ninaus for supporting me during my work periods in Graz/Austria. Special thanks to all my colleagues and friends, for all the discussions and fun we had. – Thank you : Angela Malina-Mitaroff, Evangelia Dimovasilis, Sabine Mayer, Chris Theis, Helmut Vincke, Heinz Vincke, Markus Brugger, Stefan Roesler. Thank you to my family – the roots one needs for growing. Thank you Manuela – thank you for being on my side. THIS RESEARCH WAS PERFORMED UNDER THE AUSPICES OF THE AUSTRIAN FEDERAL MINISTRY OF EDUCATION, SCIENCE AND CULTURE AS PART OF THE AUSTRIAN DOCTORAL THESIS PROGRAM AT CERN. ii Contents Kurzfassung xiii Abstract xv 1Introduction 1 1.1 History of Accelerators............................. 1 1.1.1 Electrostatic accelerator . ....................... 1 1.1.2 LINAC.................................. 1 1.1.3 Cyclotron................................ 2 1.1.4 Betatron................................. 3 1.1.5 Synchrotron ............................... 3 1.1.6 StorageRingColliderAccelerators.................. 4 1.2CERN...................................... 4 1.2.1 History.................................. 4 1.2.2 AcceleratorsatCERN......................... 5 1.2.3 Super-Proton-Synchrotron(SPS)................... 7 1.2.4 UA1................................... 7 1.3 Structure of Thesis............................... 8 2 Principles of Physics 11 2.1 The Standard Model .............................. 11 2.2 Particle Transport............................... 19 2.2.1 HighEnergyHadronInteractions................... 19 2.2.2 Mesondecay............................... 20 2.2.3 ChargedParticleScattering...................... 20 2.2.4 IntermediateEnergyRegimeandEnergyLoss............ 21 2.2.5 Detailed Description of Intermediate Energy Processes ....... 21 2.2.6 Low energy neutron processes . .................. 22 2.2.7 NuclearRecoils-ElasticScatteringandModeration......... 23 2.2.8 Thermalneutrons............................ 23 2.3MonteCarloSimulation............................ 23 2.3.1 MonteCarloBasics........................... 24 2.3.2 IntegrationwithMC.......................... 24 iii iv CONTENTS 2.3.3 ParticletransportwithMC...................... 27 2.3.4 RandomtrackingtreatmentwithinMCtransport.......... 31 2.3.5 Markovprocess-Variancereduction................. 32 3 Radiation Protection foundations 35 3.1RadiationHealthPhysics............................ 35 3.1.1 Somatic Effects............................. 35 3.1.2 Genetic Effects............................. 35 3.2 Dosimetry basics ................................ 39 3.2.1 Physicalquantities........................... 39 3.2.2 Protectionquantities.......................... 42 3.2.3 Operationalquantities......................... 44 3.2.4 Conversion coefficients......................... 44 3.3GeneralPrinciplesofRadiationProtection.................. 46 3.4 Working area classificationsatCERN(ECA5)................ 47 4 ComparisonofFLUKAandMCNPX 49 4.1FLUKA..................................... 49 4.1.1 PhysicsimplementedinFLUKA.................... 50 4.1.2 GEOMETRYpackage......................... 53 4.1.3 TRANSPORT .............................. 53 4.1.4 BIASING................................ 54 4.1.5 SCORING................................ 54 4.2MCNPX..................................... 55 4.2.1 PhysicsimplementedinMCNPX................... 56 4.3 DifferencesbetweenFLUKAandMCNPX.................. 56 4.3.1 Geometry . ............................... 56 4.3.2 Physics.................................. 57 4.3.3 Tallies, scoring............................. 57 4.3.4 Biasing.................................. 57 4.4 Geometry conversion FLUKA MCNPX.................. 60 4.5 SimplifiedGeometry.....⇒......................... 62 4.6 Results for the simplifiedGeometry...................... 62 5 Dose-rates for Experimental Point 5 of the SPS 65 5.1 Design-Re-Assessment ............................. 65 5.2 Geometry overview............................... 66 5.3Materials.................................... 68 5.4 Simulation Setup ................................ 68 5.4.1 FLUKA................................. 68 5.4.2 Coordinatesystem........................... 68 5.4.3 DetailedGeometry........................... 70 5.4.4 Loss-Setuporthesourceterm..................... 75 CONTENTS v 5.4.5 BeamandParticletransportproperties................ 76 5.4.6 Dose-equivalent............................. 78 5.5Results...................................... 80 5.5.1 General................................. 80 5.5.2 Main-shielding............................. 82 5.5.3 VerticalShafts............................. 82 5.5.4 Cross-galleriesintheshieldbridge................... 83 5.5.5 Surface Levels .............................. 83 5.5.6 Doseratecontours........................... 86 6 Particle Fluences for SPS5 91 6.1Chicane,Spiral-StaircaseandElevatorshaft................. 91 6.2FLUKA-DetectorSettings.......................... 91 6.2.1 Upwards streaming particles inside the spiral-staircase and the ele- vatorshaft................................ 92 6.2.2 Particles inside each level — ECA, ECX entries and MID-position . 95 6.2.3 Volume-detectorsforspiral-staircaseandelevator-shaft....... 96 6.3Resultsofthesimulation............................ 96 6.3.1 Boundary-crossing energy particle spectra for upwards streaming particlesinsidetheelevatorshaft................... 98 6.3.2 Boundary-crossing energy particle spectra for upwards streaming particlesinsidethespiral-staircase...................101 6.3.3 Volume passing energy particle spectra for particles inside the elevator- shaft...................................104 6.3.4 Volume passing energy particle spectra for particles inside the spiral- staircase.................................108 6.3.5 Volume passing energy particle spectra for particles inside the ECA sidesgallerycrossings..........................112 7 Conclusion 113 7.1ComparisonofFLUKAwithMCNPX.....................113 7.2 SPS5-simulations ................................114 A Tables of Dose Rates in Critical Volumes 127 B Visualization in 3D for FLUKA MC Simulation of SPS5 135 B.1Introductiontovisualization-statebeforethesis...............136 B.2 How to visualize ? ................................137 B.3Theresultswithnewvisualization.......................139 C Particle spectra for the SPS5 liaison area 141 C.1Boundary-crossingparticlespectraforLevel9................142 C.2Boundary-crossingparticlespectraforLevel7................144 vi CONTENTS C.3Boundary-crossingparticlespectraforLevel6................146 C.4Boundary-crossingparticlespectraforLevel5................148 C.5Boundary-crossingparticlespectraforLevel4................150 C.6Boundary-crossingparticlespectraforLevel3................152 C.7Boundary-crossingparticlespectraforLevel1................154 List of Figures 1.1Schematicsofacyclotron............................ 2 1.2Schematicviewofasynchrotron........................ 3 1.3AcceleratorsatCERN............................. 6 1.4 SPS-Accelerator ................................. 7 1.5 Look into the ECX5 area with the UA1-Detector experiment during as- sembly1981.................................... 8 2.1 The four classical elements after Aristotle - a 1st try of bringing symmetry intophysics................................... 11 2.2 A "periodic table" of the proton and the neutron and some of their rela- tives: The Eightfold Way - with hypercharge Y as a combination of S + B, StrangenessandBaryon-number........................ 13 2.3 The latest knowledge about the fundamental constituents of matter: six different quarks and six different leptons divided into three families. 14 2.4 Deuterium: The strong interaction binds quarks together in protons and neutronsandresidualstronginteractionbuildsupthenuclei......... 15 2.5 Charging of particles.............................. 15 2.6 Properties of the four interactions and their messenger particles ...... 16 2.7Feynman-diagramsforelectron-positronreactions.............. 17 2.8 The ultimate theory would describe the single primitive interaction out of whichtheUniversewasborn.......................... 18 2.9 Hadronic Interactions.............................. 19 56 2.10 Total Neutron cross-section for 26Fe. ..................... 22 2.11Totalamountofsolidangelforanimpingingparticle............ 28 2.12 Schematic illustration