121936146
Acceleration of Heavy Ions at the Princeton Particle Accelerator
Modifications to the Princeton Particle Accelerator (PPA) such as pulsed heavy ion source, extended range radiofrequency system, vacuum system improvements, allowed the adaptation of the 3 GeV proton synchrotron to the acceleration of heavier ions. Accele ation of nitrogen ions in a charge state of N5+ and N6+ to an energy of 4 and 7 GeV were achieved starting in July 1971. Present average intensities run at about 3 x 105 and 2 x 105 particles/sec. Expectations for acceleration of neon and argon in the near future will be discussed.
118813433
A 3 Bev high intensity proton-synchrotron
120485938
The Acceleration of Heavy Ions to Very High Energies and Their Scientific Significance
123674916
HEAVY IONS AND HIGHER PROTON CURRENTS PROPOSED FOR THE PRINCETON-- PENNSYLVANIA ACCELERATOR.
119457260
Detecting near ultraviolet radiation in the presence of visible light
We describe a system which suppresses the detection of visible sodium vapor light by a factor of about 108 relative to near ultraviolet radiation.
10342800
Acceleration of Nitrogen Ions to 7.4 Gev in the Princeton Particle Accelerator
Nitrogen ions in charge states N5+ and N6+ have been accelerated in the Princeton Particle Accelerator to 4 and 7.4 billion electron volts (Gev), respectively. An external N5+ beam of 1 x 106 particles per second has been obtained and focused to a 6-millimeter-diameter spot. The N6+ beam was about 2 x 105 particles per second. The total charge-changing collision cross section of N5+ in water vapor was determined as a function of ion energy. The improvement in vacuum necessary to increase the N5+ beam at least tenfold was calculated. The N6+ total cross section is probably smaller than that of N5+ at the higher energies.
125390779
Proton compton scattering and neutral-pion photoproduction at large angles
The differential cross sections for ..gamma..p ..-->.. ..gamma..p and ..gamma..p ..-->.. ..pi../sup 0/p have been measured from abs. value (t) = 0.7 to 4.3 GeV/sup 2/ and for incident energies in the range 2 to 6 GeV. The energy dependence of Compton scattering is well described by parton model ideas. However, the energy dependences of ..pi../sup 0/ photoproduction and the ratio of Compton scattering to ..pi../sup 0/ photoproduction are not consistent with dimensional counting arguments.
109689468
Spallation neutron source (SNS)
The Spallation Neutron Source [1], located at Oak Ridge, TN, is a state-of-the-art neutron-scattering facility presently under construction as a collaborative effort of six national laboratories. The facility is comprised of a high-power particle-accelerator system, a liquid-mercury target-moderator system, and a suite of world-class scientific instruments. One-ms-long negative-hydrogen-ion (H - ) pulses are produced by an ion source. The ion beam is accelerated to 185 MeV by normal conducting (NC) linear accelerator (linac) cavities, and further accelerated to 1 GeV by a superconducting linac [2]. The acceleration is accomplished by means of niobium superconducting radiofrequency (SRF) cavities that operate at 2.1K. The linac beam is stacked in a compressor ring, and 695-ns-long pulses are extracted onto the target at a 60-Hz rate. Neutrons are produced by spallation in the mercury, and their energy is moderated to useable levels, in part by supercritical hydrogen moderators. The simultaneous performance goals of more than one MW of initial proton beam power, 95% facility availability, and the desire for hands-on maintenance capability in the accelerator complex place significant demands on the performance and operational reliability of the technical and conventional systems. An overview of the SNS facility, including its purpose, major components, and a summary of the present status is presented, with particular emphasis on the superconducting linac and the cryogenic moderators.
1938181
Determining SUSY model parameters and masses at the LHC using cross-sections, kinematic edges and other observables.
We address the problem of mass measurements of supersymmetric particles at the Large Hadron Collider, using the ATLAS detector as an example. By using Markov Chain sampling techniques to combine standard measurements of kinematic edges in the invariant mass distributions of decay products with a measurement of a missing pT cross-section, we show that the precision of mass measurements at the LHC can be dramatically improved, even when we do not assume that we have measured the kinematic endpoints precisely, or that we have identified exactly which particles are involved in the decay chain causing the endpoints. The generality of the technique is demonstrated in a preliminary investigation of a non-universal SUGRA model, in which we relax the requirements of mSUGRA by breaking the degeneracy of the GUT scale gaugino masses. The model studied is compatible with the WMAP limits on dark matter relic density.
108754068
SRF cavity testing status and operating experience
The cryogenic system at the Meson Detector Building (MDB) has now supported over four years of testing of fully assembled SRF cavities. The Horizontal Test Stand (HTS) has tested single, fully dressed 1.3 GHz and 3.9 GHz cavities at 2 K as final qualification prior to their installation into accelerator-ready cryomodules. The MDB cryogenic system has been expanded to support an additional cavity test area, the Spoke Resonator Test (SRT) area, for 325 MHz single-spoke resonators. The SRT area currently supports 4.5 K operations for research and development of the spoke cavities with tuner and coupler. The test area addition required the design and installation of a new cryogenic transfer line extension to reach this second test area and to allow for independent operations of either cavity test system. The cryogenic performance and operational experiences of both cavity test areas, operating individually or simultaneously, will be discussed. The general reliability of operating the closed, subatmospheric he...
46688174
Diffusion of Gases in Air and Its Affect on Oxygen Deficiency Hazard Abatement
Density differences between air and released gases of cryogenic systems have been used to either require special oxygen deficiency hazard (ODH) control measures, or as a means of abatement. For example, it is not uncommon to assume that helium spills will quickly collect at the ceiling of a building or enclosure and will efficiently exit at the nearest vertical penetration or vent. Oxygen concentration reduction was found to be detectable during a localized helium spill throughout the entire 6.3 km Tevatron tunnel. This prompted us to perform diffusion tests in air with common gases used at Fermilab. The tests showed that gases, more readily than expected, diffused through an air column in the direction opposing buoyancy. Test results for helium and sulfur hexafluoride are presented. A system of tests were performed to better understand how easily released gases would fully mix with air and whether they remained fully mixed. The test results have been applied to a new system at Fermilab for ODH abatement.