Progress at LAMPF, 1992--1993

The physics of objects smaller than an atom was once a single specialty. It was called nuclear physics because its main concern was the nature and structure of atomic nuclei. But in the last decade or so a separation has taken place between the physicists who studied subatomic matter at very high energies, the so-called particle physicists, and nuclear physicists proper. The particle physicists took as their domain the nature and behavior of individual particles, rather than collective entities like a nucleus. They have gone on to higher and higher energies and ever more startling discoveries in their search for the most fundamental constituents of matter. Lately the particle physicists have experienced a certain frustration. They have been having a hard time trying to mate theory and experiment, and many of the objects they have discovered are so ephemeral that some of them are beginning to wonder whether they have anything to do with the structure of stable matter. The structure of nuclei is fundamental to the structure of stable matter, and if it ever becomes well understood, the age-old dream of making the elements one desires instead of depending on what nature gives might be a step nearer. And among the nuclear structure physicists, there is a feeling of hope and an expectation that old frustrations are about to be relieved. The nuclear physicists are building a new generation of particle accelerators, which, they expect, will give them an entirely new dimension of information about nuclear structure. Heretofore their experiments have concerned the nucleus as a whole. Now they want to study the nucleus in more detail. They want to see how small regions of it look and how individual nuclear particles behave and interact with each other within the nucleus. So far they have not had the energy available to get such data. Technology is now allowing them to build the machines that will do it. And those are now being built at several sites in the U.S., as well as in the Soviet Union, Switzerland and Canada. The machines are commonly called meson factories because one of their primary functions is the production of copious beams of pi and mu mesons with which to probe nuclei. In some cases they also yield protons and negative hydrogen ions, hydrogen atoms with an extra electron each. Each of these particles interacts in a different way with the particles in the nucleus, and each gives a different perspective on nuclear structure. Putting the perspectives together, physicists hope, will give a comprehensive picture. The meson factories bring nuclear structure physics into an energy range, hundreds of millions of electron volts, where the physics has not usually been done. The energy is necessary to get the detailed information, but achieving the energy was not the major technological stumbling block in the construction of meson factories; intensity was the problem. The particle beams have to be very intense-contain a large number of particles-to make enough of the desired reactions happen to get meaningful data. Gradual improvements in beam handling techniques have made the management of very intense beams possible, but they still give designers problems with radioactivity. There are unique problems in the handling of intensely radioactive material in targets, says Dr. R. L. Burman of Los Alamos Scientific Laboratory, speaking of the now-building Los Alamos Meson Physics Facility. The solution, he says, is to design a so-called

This technical report describes the decommissioning of the tandem accelerator at the Wright Nuclear Structure Laboratory (WNSL) at Yale University and the disposition of equipment from the WNSL experimental areas. For the past several decades Yale University hosted the Wright Nuclear Structure Laboratory with a tandem accelerator facility as a DOE Nuclear Physics-funded user laboratory and Center of Excellence. Operations of the Tandem facility ended in 2011 and a broad, new research program in nuclear physics with particular focus on experimental neutrino physics and fundamental symmetries was initiated in 2013. Removal of unused equipment and decommissioning of the WNSL accelerator and experimental facilities was a prerequisite for the new use of this laboratory space. This report describes the safe and orderly disposition of equipment from the main experimental areas and the decommissioning of the accelerator at WNSL.

Authors

In this paper an attempt is made to emphasize the major shortcomings of standard cosmology. It can be suggested that, the current cosmological changes can be understood by studying the atom and the atomic nucleus through ground based experiments. If light is coming from the atoms of the gigantic galaxy, then redshift can be interpreted as an index of the galactic atomic ‘light emission mechanism’. In no way it seems to be connected with ‘galaxy receding’. With ‘cosmological increasing (emitted) photon energy’, observed cosmic redshift can be considered as a measure of the age difference between our galaxy and any observed galaxy. If it is possible to show that, (from the observer) older galaxy’s distance increases with its ‘age’, then ‘galaxy receding’ and ‘accelerating universe’ concepts can be put for a revision at fundamental level. At any given cosmic time, the product of ‘critical density’ and ‘Hubble volume’ gives a characteristic cosmic mass and it can be called as the ‘Hubble mass’. Interesting thing is that, Schwarzschild radius of the ‘Hubble mass’ again matches with the ‘Hubble length’. Most of the cosmologists believe that this is merely a coincidence. At any given cosmic time,’Hubble length’ can be considered as the gravitational or electromagnetic interaction range. If one is willing to think in this direction, by increasing the number of applications of Hubble mass and Hubble volume in other areas of fundamental physics like quantum physics, nuclear physics, atomic physics and particle physics - slowly and gradually - in a progressive way, concepts of ‘Black hole Cosmology’ can be strengthened and can also be confirmed.

An array of three portable, pressurized ionization chambers (PICs) continued to measure external radiation levels during 1985 caused by radionuclides emitted from the Los Alamos Meson Physics Facility (LAMPF). A Gaussian-type atmospheric dispersion model, using onsite meteorological and stack release data, was tested during this study. A more complex finite model, which takes into account the contribution of radiation at a receptor from different locations of the passing plume, was also tested. Monitoring results indicate that, as in 1984, a persistent wind up the Rio Grande Valley during the evening and early morning hours is largely responsible for causing the highest external radiation levels to occur to the northeast and north-northeast of LAMPF. However, because of increased turbulent mixing during the day, external radiation levels are generally much less during the day than at night. External radiation levels during 1985 show approximately a 75% reduction over 1984 levels. This resulted from a similar percentage reduction in LAMPF emissions caused by newly implemented emission controls. Comparison of predicted and measured daily external radiation levels indicates a high degree of correlation. The model also gives accurate estimates of measured concentrations over longer time periods. Comparison of predicted and measured hourly values indicates that the model generally tends to overpredict during the day and underpredict at night. 9 refs., 14 figs., 13 tabs.

This paper will cover a few of the alignment problems solved by conventional optical tooling techniques at the Los Alamos Meson Physics Facility (LAMPF). The LAMPF accelerator is a large linear proton accelerator used in physics experiments. The alignment techniques and expertise developed on the LAMPF project have been utilized on several other Los Alamos Scientific Laboratory projects including alignment of laser systems, normal physics experiments, machine tools and normal mechanical inspection jobs. The topics to be discussed are conventional optical tooling setups, non-conventional setups, special and/or unique alignment targets and the utilization of an optical tooling dock. The relationship between alignment tolerances, component design, support structure and/or mounting base design and the specific optical tooling setups will be the major theme in the paper.© (1980) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In recent years there has been considerable growth in research in so-called 'interface' areas where nuclear physics, particle physics and astrophysics meet; sharing common goals and language, as well as instrumentation techniques. Examples include: Probing the standard model by measuring elements of the CKM matrix The use of colliders and detectors with access to the highest energies to search for the underlying structure of matter and energy Fundamental interactions at the nuclear and particle level required to understand processes from solar burning to supernovae Neutrino physics; including oscillations, mass and interactions probing the standard solar model Hadronic physics dealing with the interactions, binding and structure of the strongly interacting particles under various conditions The increased use of 4 detectors in low-energy nuclear physics to select specific processes of interest. These are only a few examples of what has become a major meeting place for much of the exciting physics of the early 21st Century. In today's science, the spectrum of particles, the nucleus as well as the large-scale components of the universe, are our laboratories for testing and understanding nature.These exciting areas of cross-over require much further research and exploration. The Editorial Board and staff of Journal of Physics G: Nuclear and Particle Physics wish to strengthen their support for physicists working in such areas of intersection. To make our coverage of these interconnections more explicit, we have redrafted our scope statement as follows:Theoretical and experimental topics in the physics of elementary particles and fields, intermediate-energy physics and nuclear physics. The particle astrophysics section includes all aspects of experimental and theoretical research into cosmic rays, nuclear and particle astrophysics, gamma ray astronomy, neutrino astrophysics and dark matter. We also welcome articles from all areas of interface between these fields.We would like to invite all physicists working on these topics to publish their work in the pages of J.Phys.G. Naturally we shall continue to welcome outstanding research in our core nuclear and particle physics areas.Since its launch in 1975, J.Phys.G has had a broad scope covering all aspects of the physics of elementary particles, nuclear physics, and nuclear and particle astrophysics. We have always felt this provides the journal's authors and readers with a unique overview of these increasingly interconnected subjects.When you publish in J.Phys.G you'll benefit from fast and impartial peer review, with an average receipt-to-first decision time for papers of 58 days. We strive to provide outstanding author service with online article submission, tracking of manuscripts and electronic refereeing. Publishing with us provides your paper with wide international visibility in print and online at www.iop.org/journals/jphysg. As well as being accessible to our subscribers, each new paper is freely available to all for 30 days on our Website

A progress report is given on the upgraded facilities at the Los Alamos Meson Physics Facility to support (p, n) and (n, p) charge-exchange studies at intermediate energies. These include a beam-swinger system, a 600 m flight path and neutron polarimeter for (p, n) reactions, and a medium-resolution spectrometer with a focal-plane polarimeter for (n, p). A general overview of the physics program being planned is also presented.

These notes are an outgrowth of an advanced undergraduate course taught at the University of Maryland, College Park. They are intended as an introduction to various aspects of particle and nuclear physics with an emphasis on the role of symmetry. The basic philosophy is to introduce many of the fundamental ideas in nuclear and particle physics using relatively sophisticated mathematical tools -- but to do so in as a simplified a context to explain the underlying ideas. Thus, for example, the Higgs mechanism is discussed in terms of an Abelian Higgs model. The emphasis is largely, but not entirely theoretical in orientation. The goal is for readers to develop an understanding of many of the underlying issues in a relatively sophisticated way.

A foil activation dosimetry experiment was conducted at the Clinton P. Anderson Los Alamos Meson Physics Facility (LAMPF) beam stop area to characterize the radiation environment and to identify techniques for spallation radiation measurements. The measured total spallation neutron flux outside the primary proton beam was 5.5 × 1017 neutrons/m2/s/mA ±7%. A previous Monte Carlo calculation gave a total spallation neutron flux in approximately the same location as the dosimetry package of 6.0 × 1017 neutrons/m2/s/mA ±3%. Comparison between the measured and calculated neutron fluxes shows good agreement. To extend the characterization, additional spallation cross sections for energies up to 800 MeV and the use of foils sensitive to the epithermal energy range are needed.

An essential element of any fusion or fission reactor materials development effort is the availability of irradiation facilities for conducting radiation effects experiments. A Radiation Effects Facility (REF) was provided for such studies at the Los Alamos Meson Physics Facility. Neutron spectra at the REF can be tailored to approximate those in either a fusion or fission reactor, while providing flux levels of approximately 1.4 x 10/sup 18/ m/sup -2/ s/sup -1/ at design maximum beam currents. An intranuclear-cascade/evaporation model was used for computing neutron production. Detailed Monte Carlo neutron transport calculations were performed, some of which were experimentally verified in a foil dosimetry program. Such calculations provide the radiation effects experimentalist with information on spatial-spectral variations of the neutron flux over much of the easily accessible experimental volume (approximately 19,000 cm/sup 3/), which includes irradiation specimen capsule locations and a rabbit tube. From these data, radiation damage indices such as ratios of parts per million helium to displacements per atom can be calculated and compared to those anticipated in fusion reactor blankets or fast fission reactor cores.

Construction of the Japan Proton Accelerator Research Complex (J-PARC) has been in progress under a cooperation of two institutions, KEK and Japan Atomic Energy Agency (JAEA). Most of the accelerator buildings have been already constructed, and the beam commissioning of the proton injector is about to start. Recently, the first Program Advisory Committee (PAC) meeting was held to consider the proposals in nuclear and particle physics at J-PARC. In this talk, the initial experimental program in strangeness nuclear physics is described based on the approvals by this committee.PACS21.80.+a Hypernuclei25.80.Nv Kaon-induced reactions

Maurice Goldhaber

An array of three portable, pressurized ionization chambers (PICs) measured short-term external radiation levels produced by air activation products from the Los Alamos Meson Physics Facility (LAMPF). The monitoring was at the closet offsite location, 700-900 m north and northeast of the source, and across a large, deep canyon. A Gaussian-type atmospheric dispersion model, using onsite meteorological and stack release data, was tested during their study. Monitoring results indicate that a persistent, local up-valley wind during the evening and early morning hours is largely responsible for causing the highest radiation levels to the northeast and north-northeast of LAMPF. Comparison of predicted and measured daily external radiation levels indicates a high degree of correlation. The model also gives accurate estimates of measured concentrations over longer periods of time.

An array of three portable, pressurized ionization chambers (PICs) measured external radiation levels during 1986 and 1987 caused by radionuclides emitted from a 30-m stack of the Los Alamos Meson Physics Facility (LAMPF). Three PICs were located from 700 to 900 m north to northeast of the release stack, across a 120-m-deep canyon, and at the closest off-site location. Four additional PICs were deployed during 1987 at various sites and directions, at distances varying from 550 to 2700 m downwind of the stack. Winds were measured near the source and 700 m downwind, across a deep canyon. Analysis of monitoring data confirmed that a predominant mountain-valley wind up the Rio Grande Valley during the evening and early morning transported the emissions to the north-northeast and northeast of LAMPF, causing the highest external atmospheric radiation levels there. Daytime winds are southerly and southeasterly, transporting more radionuclides to the north and northwest. Because of increased turbulence, external radiation levels were generally lower during the day.