| 1. |
- Alcorn, J, et al.
(författare)
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Basic instrumentation for Hall A at Jefferson Lab
- 2004
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:3, s. 294-346
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Tidskriftsartikel (refereegranskat)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
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| 2. |
- Ahrens, J., et al.
(författare)
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Calibration and survey of AMANDA with the SPASE detectors
- 2004
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 522:3, s. 347-359
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Tidskriftsartikel (refereegranskat)abstract
- We report on the analysis of air showers observed in coincidence by the Antarctic Muon and Neutrino detector array (AMANDA-B10) and the South Pole Air Shower Experiment (SPASE-1 and SPASE-2). We discuss the use of coincident events for calibration and survey of the deep AMANDA detector as well as the response of AMANDA to muon bundles. This analysis uses data taken during 1997 when both SPASE-1 and SPASE-2 were in operation to provide a stereo view of AMANDA. © 2003 Elsevier B.V. All rights reserved.
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| 3. |
- Ahrens, J., et al.
(författare)
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Measurement of the cosmic ray composition at the knee with the SPASE-2/AMANDA-B10 detectors
- 2004
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Ingår i: Astroparticle physics. - : Elsevier. - 0927-6505 .- 1873-2852. ; 21:6, s. 565-581
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Tidskriftsartikel (refereegranskat)abstract
- The mass composition of high-energy cosmic rays at energies above 1015 eV can provide crucial information for the understanding of their origin. Air showers were measured simultaneously with the SPASE-2 air shower array and the AMANDA-B10 Cherenkov telescope at the South Pole. This combination has the advantage to sample almost all high-energy shower muons and is thus a new approach to the determination of the cosmic ray composition. The change in the cosmic ray mass composition was measured versus existing data from direct measurements at low energies. Our data show an increase of the mean log atomic mass 〈lnA〉 by about 0.8 between 500 TeV and 5 PeV. This trend of an increasing mass through the "knee" region is robust against a variety of systematic effects. © 2004 Elsevier B.V. All rights reserved.
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| 4. |
- Watson, C.A., et al.
(författare)
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A review of farm-scale nutrient budgets for organic farms as a tool for management of soil fertility
- 2002
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Ingår i: Soil use and management. - 0266-0032 .- 1475-2743. ; 18:SUPPL., s. 264-273
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Tidskriftsartikel (refereegranskat)abstract
- On organic farms, where the importation of materials to build/maintain soil fertility is restricted, it is important that a balance between inputs and outputs of nutrients is achieved to ensure both short-term productivity and long-term sustainability. This paper considers different approaches to nutrient budgeting on organic farms and evaluates the sources of bias in the measurements and/or estimates of the nutrient inputs and outputs. The paper collates 88 nutrient budgets compiled at the farm scale in nine temperate countries. All the nitrogen (N) budgets showed an N surplus (average 83.2 kg N ha-1 yr-1). The efficiency of N use, defined as outputs/inputs, was highest (0.9) and lowest (0.2) in arable and beef systems respectively. The phosphorus (P) and potassium (K) budgets showed both surpluses and deficits (average 3.6 kg P ha-1 yr-1, 14.2 kg K ha-1 yr-1) with horticultural systems showing large surpluses resulting from purchased manure. The estimation of N fixation and quantities of nutrients in purchased manures may introduce significant errors in nutrient budgets. Overall, the data illustrate the diversity of management systems in place on organic farms, and suggest that used together with soil analysis, nutrient budgets are a useful tool for improving the long-term sustainability of organic systems.
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| 5. |
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| 6. |
- Szita, S., Fazakerley, A.N., Carter, P.J., James, A.M., Travnicek, P., Watson, G., André, M., Ericsson, A. and Torkar, K.
(författare)
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Cluster PEACE observations of electrons of spacecraft.
- 2001
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Ingår i: Annales Geophysicae. ; 19, s. 1721-1730
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Tidskriftsartikel (refereegranskat)abstract
- The two PEACE (Plasma Electron And Current Experiment) sensors onboard each Cluster spacecraft sample the electron velocity distribution across the full 4 ¡ solid angle and the energy range 0.7eV to 26keV with a time resolution of 4 sec-onds. We present h
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| 7. |
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| 8. |
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| 9. |
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| 10. |
- Keil, M., et al.
(författare)
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High levels of alkali-metal storage in thin films of hexa-peri-hexabenzocoronene
- 2002
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Ingår i: Journal of Chemical Physics. - : AIP Publishing. - 0021-9606 .- 1089-7690. ; 116:24, s. 10854-10860
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Tidskriftsartikel (refereegranskat)abstract
- The results of the doping of molecular solid films of the medium-sized aromatic hydrocarbon hexa-peri-hexabenzocoronene (HBC), using lithium or sodium atoms were presented. The evolution of the valence band electronic structure was monitored by x-ray photoelectron spectroscopy and studied by ultraviolet photoelectron spectroscopy. Results indicated that n-doping depended on the type of alkali-metal atom employed and on the molecular order of the film. The smaller Li ion was found to have a stronger influence on the electronic structure than Na ions. These results revealed the potential use of the graphene materials in lithium-ion batteries with a high charge-storage capacity.
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