[en] An accumulator-storage ring arrangement with very small Δp/p, similar to the situation at CERN, is suggested and recommended for future anti p physics at LAMPF II

No abstract available

[en] The Boulder Atmospheric Observatory (BAO) tower was constructed and became operational in 1977. This 300-m tower, although originally supporting the development and improvement of ground-based remote sensing devices, has been used extensively in the study of the atmospheric boundary layer as well as plume dispersion and air quality. It was used in studies of the Denver Brown Cloud during the winters of 1987-1988 and 1996-1997. Located about 20 km east from the foothills of the Rocky Mountains, it is subject to a wide range of weather conditions ranging from night-time drainage winds with a low-level jet structure, to down-slope wind storms and upslope snow storms. During the summer of 2007, three levels of CO₂ and CO gas sampling (at 22, 100, and 300 m) were added as the tower became part of the NOAA ESRL/Global Monitoring Division CO₂ tall-tower network. The tower's location in complex terrain and its proximity to urban areas will provide a number of challenges in the interpretation of the data it provides. In this paper, we will describe some of the history of the tower in past air quality studies, examples of its complex meteorological setting and initial examples comparing diurnal variation in CO₂ and CO with boundary layer depths and structure observed with an acoustic sounder

[en] The generation of atmospheric pressure microplasmas using microwave resonators is promising for many applications due to the possibility of high electron densities and low electrode degradation. In particular, such plasmas may help enable reconfigurable metamaterials operating from GHz to THz. Since plasma metamaterials may require the generation of tens to hundreds of plasmas, it is important to find ways to reduce the power required for plasma breakdown. Here, we study gold and silver microwave split-ring resonators (SRRs) with a variety of materials near the interelectrode gap (Cu, CuO nanowires, aluminum oxide). We focus on those fabricated using a traditional thick film technique, screen-printing, and using fs- and ns-laser ablation. The use of laser ablation allows us to explore small interelectrode gap sizes (7–100 μm) and the use of different lasers and laser parameters enables us to produce a variety of microstructures. We utilize Weibull statistics to examine breakdown in atmospheric pressure Ar with and without deep ultraviolet illumination of SRRs. Fabrication methods and materials are shown to influence both Q-factor of the SRRs and breakdown voltage independently. It is found that superior performance in terms of breakdown voltage and consistency in breakdown is related to Weibull modulus. The power requirement for breakdown varied as widely as an order of magnitude depending on fabrication method and material used for the SRRs. Furthermore, we consider the performance differences seen between various resonators and relate this to microstructure/material which suggests that field-emission may play a role in providing the seed electrons required for breakdown. This need for seed electrons appears to be especially important for gap sizes of 40 μm and smaller. (paper)

[en] High-statistics measurements of the absolute differential cross section for n-p scattering have been made over neutron c.m.-system scattering angles 9.5⁰ < theta* < 64.5⁰. The statistical error is 1.7 to 3.3% for 2⁰-wide angular bins, and the systematic error is 2.7 to 3.3%. The cross section is fitted by dsigma/dΩ* = A exp(bt), with A = 10.27 +- 0.36 mb/sr, b = 5.00 +- 0.05 and 0.01 5 -t 5 0.39 (GeV/c)². For the ratio of the real to the imaginary part of the forward-scattering amplitude we obtained α/sub n/ - 0.43 +- 0.04, consistent with other less precise determinations of α/sub n/

[en] A frequently stated common goal of all relativistic heavy ion experiments is the observation of quark-gluon plasma (QGP). This postulated state of matter results from the QCD prediction of a phase transition in hadronic matter at sufficiently high energy densities. Several specific signatures indicating the creation of such a state are theoretically predicted and sought in many experiments. These include large soft photon and lepton production, the suppression of J/ψ production, strangeness enhancement etc. In addition to these specific signatures one or both of two experimental observables are used by most experiments for the global characterization of heavy ion collisions. These are the total produced transverse energy (E_T), and the number of the produced charged particles (N_Ch). Both observables are closely related to thermodynamic variables commonly used in theory to describe the conditions necessary for the formation of such states. The importance of these observables is further enhanced by the fact that it is relatively simple for either one of them to be used at the trigger level in order to tag the centrality of a given interaction. In this development project the authors are using silicon detectors to measure the total number of charged particles produced in a heavy ion collision as well as to measure their production as a function of pseudorapidity. Unless calorimetric coverage over a large solid angle is necessary for other reasons measuring N_Ch instead of E_T is clearly more practical and less expensive

[en] The RHIC spin program requires excellent polarimetry so that the knowledge of the beam polarization does not limit the errors on the experimental measurements. However, polarimetry of proton beams with energies higher than about 30 GeV poses a difficult challenge. For polarization monitoring during operation, a fast and reliable polarimeter is required that produces a polarization measurement with a 10% relative error within a few minutes. The p-Carbon elastic scattering in the Coulomb-Nuclear-Scattering (CNI) region has a calculable and large analyzing power, but detecting the recoil carbon needs sophisticated detector system and a very thin target. Experiment has been planned in the AGS. This paper describes the experimental setup in the AGS

[en] Acceleration of polarized protons is one of the exciting features of the new Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. Measurements of beam polarization are required both for experiments and the accelerator tuning. Elastic scattering in the Coulomb nuclear interference (CNI) region of polarized proton beams on a carbon target demonstrates asymmetry which can be used to build a polarimeter. The methods proposed for a RHIC CNI polarimeter were tested with the AGS polarized beam in the E950 experiment. A 21.7 GeV/c polarized proton beam was scattered on an extremely thin carbon ribbon target located in the AGS ring. Two symmetrical arms consisting of silicon strip detectors (SSD) and a micro channel plate (MCP) were used to identify recoil carbon. Data obtained demonstrates a good identification of the reaction by the apparatus and a significant analyzing power. A RHIC polarimeter setup with 4 SSDs but without MCPs will be used to commission RHIC with polarized protons and for the first spin physics running in 2001

[en] Strange Dibaryons, six valence-quark hadrons constructed from one or more strange quarks, are predicted to have greater binding than dibaryons in the non-strange sector. The flavor-singlet dibaryon with quark structure open-quotes uuddssclose quotes is of particular theoretical and experimental interest. A brief review of the status of H dibaryon studies is presented with emphasis on experiment E813 currently taking data at the AGS

[en] The authors present experimental results on rapidities, kaon and pion p_t-spectra, and two-pion correlation functions obtained for central 14.6 A GeV Si+Al and Si+Pb collisions. (HSI)