THE ECONOMIC GROWTH AND DEVELOPMENT AND THE NATURAL ENVIROMENT

The problems of the environment are complex and closely related to a country’s social-economic status, to its progress in general. The economic growth must not deteriorate the environment; in fact it has to guarantee a constant protection correlated with the improvement of the life quality. The contradiction between the economic growth and the natural environment has suffered transformations during time, the adaptation of the economic growth to the natural resources’ volume and quality at a certain moment becoming a necessity as well as the rational utilization of both natural resources and environmental conditions. We do not have to stop the economic growth and development in order to prevent or eliminate pollution; we have, in fact, to obviate the causes that make the economic growth and development to be accompanied by pollutioneconomic growth, economic development, sustainable development

Investigation of open-loop beam motion at low frequencies at the APS

Sources of transverse beam motion in the APS storage ring have been investigated for ground-motion- and water-system-induced vibrations of the magnet and vacuum systems, and for power supply ripple. The displacement of magnets in a bandwidth of 4-30 Hz have been reduced significantly by inserting viscoelastic damping pads between the girder supports and pedestals, and by welding the magnet cooling headers to the ceiling of the storage ring tunnel. Current ripple on magnet power supplies was identified as a source of horizontal beam motion. Beam motion was measured without the closed-orbit feedback system activated. At {beta}{sub x} = 15.4 m and {beta}{sub y} = 10.4 m the rms beam motion in the 0.02-30 Hz band was 22.7 {mu}m and 6.3 {mu}m in the horizontal and verticle planes, respectively. A few narrow-band structures of the horizontal beam motion spectrum in the 1-4 Hz band have to be investigated further to identify the sources

Passive vibration damping of the APS machine components

The accelerator and beamline components of the APS have stringent vibration criteria in order to meet the beam stability requirements. For instance, the vibration amplitude of the storage ring quadrupoles is restricted to 0.11 {mu}m (rms) over a frequency range of 4--50 Hz. Damping pads, consisting of thin viscoelastic f`ilms sandwiched between stainless steel plates, have been designed for passive vibration damping. Results presented in this paper show that the damping pads under the storage ring girder-magnet assemblies reduced the vibration amplification factor Q from over 100 to 8. The broad band rms motion of the magnets was reduced by a factor of 2.5 to 3. Preliminary results for a monochromator housing show a potential use of such damping pads for vibration control of beamline components. Radiation and creep effects on the damping pads` performance are considered

The application of viscoelastic damping materials to control the vibration of magnets in a synchrotron radiation facility

The Advanced Photon Source at Argonne National Laboratory is a facility signed to produce extremely brilliant x-rays for materials, chemistry, and medical research. In this facility, positrons are first produced and accelerated to energy levels of 7-GeV. The positrons are then injected into a 1104-meter circumference storage ring where they circulate, for periods up to 18 hours, and emit high-intensity x-rays as the circulating beam is oscillated by insertion devices. The beam is positioned and its size controlled by large electromagnets. The magnets are mounted on 200 individual girder assemblies, with each assembly having several magnets mounted on it. Of prime concern are the girder assemblies supporting the quadrupoles, or focusing, magnets. These magnets must satisfy very stringent vibration criteria, with motion restricted to less than a micron over a broad frequency range. Therefore, amplification at resonant frequencies of the girder assemblies must be minimized. To accomplish this, various viscoelastic damping materials and their placement in the system were evaluated. As a result of the study, dynamic magnification factors were reduced to a value of five with no detectable increase in static deflection. The damping materials and methods used to accomplish this in massive systems of 7,500 kg or greater, where the displacements are on the of 0.1 micron or less, will be useful for many less demanding situations

Upgraded cavities for the positron accumulator ring of the APS

Upgraded versions of cavities for the APS positron accumulator ring (PAR) have been built and are being tested. Two cavities are in the PAR: a fundamental 9.8-MHz cavity and a twelfth harmonic 117.3-MHz cavity. Both cavities have been manufactured for higher voltage operation with improved Q-factors, reliability, and tuning capability. Both cavities employ current-controlled ferrite tuners for control of the resonant frequency. The harmonic cavity can be operated in either a pulsed mode or a CW mode. The rf properties of the cavities are presented

Performance of the vibration damping pads in the APS storage ring

Abstract Beam stability goals for the APS storage ring require that its quadrupoles' vibrations be limited to 110 nm (rms, 4-50 Hz). Viscoelastic damping pads were installed under the girders in order to bring down the vibration levels to within the specified range. This paper presents the design of the damping pads and the results of recent vibration tests to evaluate their performance

Analysis Efforts Supporting NSTX Upgrades

The National Spherical Torus Experiment (NSTX) is a low aspect ratio, spherical torus (ST) configuration device which is located at Princeton Plasma Physics Laboratory (PPPL) This device is presently being updated to enhance its physics by doubling the TF field to 1 Tesla and increasing the plasma current to 2 Mega-amperes. The upgrades include a replacement of the centerstack and addition of a second neutral beam. The upgrade analyses have two missions. The first is to support design of new components, principally the centerstack, the second is to qualify existing NSTX components for higher loads, which will increase by a factor of four. Cost efficiency was a design goal for new equipment qualification, and reanalysis of the existing components. Showing that older components can sustain the increased loads has been a challenging effort in which designs had to be developed that would limit loading on weaker components, and would minimize the extent of modifications needed. Two areas representing this effort have been chosen to describe in more details: analysis of the current distribution in the new TF inner legs, and, second, analysis of the out-of-plane support of the existing TF outer legs

Progress on the NSTX Center Stack Upgrade

The National Spherical Torus Experiment (NSTX) will be upgraded to provide increased toroidal field, plasma current and pulse length. This involves the replacement of the so-called center stack, including the inner legs of the Toroidal Field (TF) coil, the Ohmic Heating (OH) coil, and the inner Poloidal Field (PF) coils. In addition the increased performance of the upgrade requires qualification of remaining existing components for higher loads. Initial conceptual design efforts were based on worst-case combinations of possible currents that the power supplies could deliver. This proved to be an onerous requirement and caused many of the outer coils support structures to require costly heavy reinforcement. This has led to the planned implementation of a Digital Coil Protection System (DCPS) to reduce design-basis loads to levels that are more realistic and manageable. As a minimum, all components must be qualified for the increase in normal operating loads with headroom. Design features and analysis efforts needed to meet the upgrade loading are discussed. Mission and features of the DCPS are presented