University of Report Series

NO0000041 UNIVERSITY OF DEPARTMENT OF PHYSICS SECTION for NUCLEAR PHYSICS AND ENERGY PHYSICS Annual Report January 1 - December 31 -1998 Department of Physics, University of Oslo P.O.Box 1048 Blindern N-0316 Oslo, Norway UIO/PHYS/99-04 Received: 1999-08-27 ISSN-0332-5571 REPORT SERIES ^fittH-i- .***•** ; •t 31- 18 oup SECTION for NUCLEAR PHYSICS AND ENERGY PHYSICS Annual Report January 1 - December 31 -1998 Department of Physics, University of Oslo P.O.Box 1048 Blindern N-0316 Oslo, Norway UIO/PHYS/99-04 Received: 1999-08-27 ISSN-0332-5571 Contents 1 Introduction 7 2 Personnel 9 2.1 Research Staff 9 2.2 Technical Staff 10 3 Cyclotron operation and external user projects 11 3.1 Operation and Maintenance 11 3.2 External user projects 11 3.2.1 Production of 18F-fluorodeoxyglucose for medical PET-imaging ... 11 3.2.2 Basic Nuclear Chemistry Research 12 3.2.3 The application and study of 2UAt 13 4 Data Acquisition and Analysis 14 4.1 Introduction 14 4.2 Configuration 14 4.3 Acquisition and Data Analysis Software 17 4.4 Progress of the SIRI Data-Acquisition System Development 18 5 Nuclear Instrumentation 20 5.1 The CACTUS Detector 20 5.2 Properties of the CACTUS Detector Array 20 5.3 The SIRI Strip Detector Project 22 5.3.1 The Detectors 23 5.3.2 The Chip Read-Out System . 24 5.3.3 The Data Acquisition System 24 5.4 Background Radiation from Target Impurities 25 2 5.5 Liquid Nitrogen Filling System for Ge Detectors 26 5.6 The New Eventbuilder Single Board Computer 28 6 Experimental Nuclear Physics 30 6.1 Experiments at the Oslo Cyclotron 30 6.1.1 Introduction 30 6.1.2 Temperature and Heat Capacity of Rare-Earth Nuclei 31 6.1.3 The 162Dy(3He,a) and 162Dy(3He,3He') Reactions 34 6.1.4 Structure and Decay Properties of Heated 166Er 34 6.1.5 Direct 7-Feeding of the Ground State Band in Rare Earth Nuclei . 37 6.1.6 Gamma-Ray Angular Correlation and Polarization Measurements of the 163Dy(3He,cry)162Dy Reaction 38 6.1.7 Back-Shifted Fermi Gas Model 40 6.1.8 Simultaneous Extraction of Level Density and 7-Ray Strength Function 41 6.1.9 Simulation of Statistical 7-Ray Spectra . 44 6.1.10 High-Resolution Measurements of Level Densities and 7-Ray Strength Functions 44 6.1.11 iif-Hindrance in Primary 7-Decay after Thermal and ARC Neutron Capture 46 6.1.12 Spectroscopy with Entry-State Selection: Nuclides Produced in the Reaction a+28Si 47 6.2 High Spin Properties of Nuclear States 50 6.2.1 Triaxial Superdeformed Bands in 164Lu and Enhanced El Decay-out Strength 50 6.2.2 Triaxial Superdeformed Bands in 163Lu 52 6.2.3 A Search for Exotic Rotational Structures in 167-169Hf by the Semi- Symmetric Cold Fusion Reaction 76Ge+96Zr 54 6.2.4 Octupole Structures in 226U 56 6.2.5 Shape coexistence in mIr 57 6.3 High and Intermediate Energy Nuclear Physics 59 6.3.1 Introduction 59 6.3.2 Strangeness Production in Ultrarelativistic Nucleus-Nucleus and Proton- Nucleus Collisions - The WA97 and NA57 Experiments 59 6.3.3 Hyperon production in Pb-Pb collisions at 158 A Gev/c 70 6.3.4 The BRAHMS - Broad RAnge Hadron Magnetic Spectrometer - Experiment at the RHIC Accelerator 71 3 6.3.5 Track recognition in BRAHMS using the Hough transform method . 74 6.3.6 A Large Ion Collider Experiment (ALICE) at the CERN LHC .... 76 6.3.7 The Spin of the Nucleons 77 6.4 Radiation physics and radiation protection 79 6.4.1 Radon and radon progeny in indoor air 79 6.4.2 Radon concentrations in groundwaters 81 7 Theoretical nuclear physics and nuclear astrophysics 83 7.1 Introduction 83 7.2 Nuclear structure research 84 7.2.1 Study of odd-mass N = 82 isotones with realistic effective interactions 84 7.2.2 Effective interactions and shell model studies of heavy tin isotopes . 84 7.2.3 Shell model studies of the proton drip line nucleus 106Sb 85 7.2.4 Ground state magnetic dipole moment of 135I 85 7.2.5 New island of ms isomers in neutron-rich nuclei around the Z = 28 and N = 40 shell closures 86 7.2.6 Shell model Monte Carlo studies of neutron-rich nuclei in the ls-Orf- lp-0/ shells 86 7.2.7 Towards the solution of the Cp/C\ anomaly in shell-model calcula- tions of muon capture 87 7.3 Hadron properties in the medium: Nuclear structure aspect 88 7.3.1 Hyperon properties in finite nuclei using realistic YN interactions . 88 7.4 Nuclear astrophysics and dense matter studies 89 7.4.1 Phase transitions in rotating neutron stars 89 7.4.2 Phase transitions in neutron stars and maximum masses 90 7.4.3 Phases of dense matter in neutron stars 90 7.4.4 Structure of ^-stable neutron star matter with hyperons 90 7.4.5 Neutrino emissivities in neutron stars 90 7.4.6 Vortex lines in the crust superfluid of a neutron star 91 7.5 Superfluidity in infinite matter 92 7.5.1 Nucleon-nucleon phase shifts and pairing in neutron matter and nuclear matter 92 7.5.2 Minimal relativity and 3Si-3Di pairing in symmetric nuclear matter 93 4 3 3 (•.5.3 P2- ^2 pairing in neutron matter with modern nucleon-nucleon potentials 93 7.6 Nucleon-nucleon interactions and nuclear many-body theory 94 7.6.1 Phaseshift equivalent NN potentials and the deuteron 94 7.6.2 Perturbative many-body approaches 94 7.7 Project: The Foundation of Quantum Physics 94 7.7.1 Description of vacuum in quantum field theory 94 8 Energy Physics 96 8.0.2 Solar heating and cooling systems at the Sun-Lab 96 8.0.3 Efficiency measurements of a solar thermal heating system 98 8.0.4 Calibration of the measuring equipment 101 8.0.5 Data acquisition system for a building integrated solar heating system 102 8.0.6 Simulation of active thermal solar collector systems 104 8.0.7 Transformation of the solar insolation values on sloped surfaces to horizontal surface values 104 8.0.8 A Combined Thermal and Photovoltaic Solar Energy Collector . 105 8.0.9 Stand alone solar system for domestic hot water heating 107 8.0.10 Regulation and Energy Monitoring in Low Temperature Heating Sys- tems 108 8.0.11 A study of heat distributors in wooden floor heating systems .... 109 9 Seminars 111 10 Committees, Conferences and Visits 112 10.1 Committees and Various Activities 112 10.2 Conferences 113 11 Theses, Publications and Talks 116 11.1 Theses 116 11.1.1 Cand. Scient. Theses 116 11.1.2 Dr. Scient. Theses 116 11.2 Scientific Publications and Proceedings 116 11.2.1 Nuclear Physics and Instrumentation 116 11.2.2 Energy 120 5 11.2.3 Radiation Research 120 11.2.4 Other Fields of Research 121 11.3 Reports and Abstracts 121 11.3.1 General 121 11.3.2 Nuclear Physics and Instrumentation 121 11.3.3 Energy 122 11.3.4 Radiation Research 122 11.4 Scientific Talks and Conference Reports 123 11.4.1 Nuclear Physics and Instrumentation 123 11.4.2 Energy 127 11.4.3 Radiation 127 11.5 Popular Science 128 11.5.1 Books 129 11.6 Pedagogical reports and talks 129 11.7 Science Policy and Science Philosophy 130 Chapter 1 Introduction The present annual report from the Section for Nuclear- and Energy Physics is exclusively a research report. The scientific staff members are also strongly engaged in the university course teaching at all levels, and in various administrative duties, not reported here. The Nuclear- and Energy Physics section 1998 staff counted 10 members in permanent positions, two post. doc. fellows, one professor II (1/5 position for 5 years), 13 research fellows, and 2 engineers. Despite the very professional and persistent efforts of the technical staff, the comprehensive experimental activities are in strongly need for more technical support. The lack of technical positions is however a common university problem, of which Norwegian universities have more than their fair share. Experimental and theoretical nuclear physics is, and has always been, the main fields of research activity in the section. However, in the early seventies a growing research activity within solar energy was initiated, primarily based on the experimental and instrumentation expertise among the section members. This research, both fundamental and applied, has proven popular among students, and also among funding sources. The section has a long tradition in Radiation Research. In particular, fundamental pioneer work on Radon research has been done in this section through the years. This research is continued in close cooperation with the Norwegian Radiation Protection Authority. Furthermore, lately the demand for beamtime on the local cyclotron has increased consid- erably. In fact, at present the accelerator capacity is fully used, the capacity set by the availability of skilled operation staff and the necessary time for scheduled and unscheduled maintenance. The beamtime for external users now exceeds the beamtime allocated to nuclear physics experiments. In order to meet the urgent need for organizing and to give priority to the different accelerator based activities, a cyclotron board, with internal and external members, has now been established. The total beamtime used for experiments in 1998 was 1051 hours. 52 days were used by the Nuclear Physics section, 70 days by the University of Oslo Nuclear Chemistry section, and the Norwegian Cancer Hospital used the cyclotron for 12 days.

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