19,590 research outputs found
Langley program of GaAs solar cells
A brief overview of the development of GaAs solar cell technology is provided. An 18 to 20 percent AMO efficiency, stability under radiation and elevated-temperature operation, and high power-to-weight ratio are among the factors studied. Cell cost and availability are also examined
Observation and mechanism of direct-current quenching of alternating-current electro- luminescence in typical zinc sulfide phosphors
Direct current quenching of alternating current electroluminescence in zinc sulfide phosphor
GaAs solar cells
The major thrusts proposed for GaAs were increased efficiency and improved radiation damage data. Current laboratory production cells consistently achieve 16 percent AMO one-Sun efficiency. The user community wants 18-percent efficient cells as soon as possible, and such a goal is though to be achievable in 2 years with sufficient research funds. A 20-percent research cell is considered the efficiency limit with current technology, and such a cell seems realizable in approximately 4 years. Future efficiency improvements await improved substrates and materials. For still higher efficiencies, concentrator cells and multijunction cells are proposed as near-term directions
Radiation damage in GaAs solar cells
Recent results of electron and proton irradiation and annealing of GaAs solar cells are presented along with some implications of these results. A comparison between the energy-levels produced by protons and by electrons which are not stopped in the material indicate that the damage produced by protons and electrons may be qualitatively different. Thus, annealing of proton damage may be very different from the annealing of electron damage
Space Laser Power Transmission System Studies
Power transmission by laser technique is addressed. Space to Earth and space to space configurations are considered
Method for detecting pollutants
A method is described for detecting and measuring trace amounts of pollutants of the group consisting of ozone, nitrogen dioxide, and carbon monoxide in a gaseous environment. A sample organic solid material that will undergo a chemical reaction with the test pollutant is exposed to the test environment and thereafter, when heated in the temperature range of 100-200 C., undergoes chemiluminescence that is measured and recorded as a function of concentration of the test pollutant. The chemiluminescence of the solid organic material is specific to the pollutant being tested
Report of the Higgs Working Group of the Tevatron Run 2 SUSY/Higgs Workshop
This report presents the theoretical analysis relevant for Higgs physics at
the upgraded Tevatron collider and documents the Higgs Working Group
simulations to estimate the discovery reach in Run 2 for the Standard Model and
MSSM Higgs bosons. Based on a simple detector simulation, we have determined
the integrated luminosity necessary to discover the SM Higgs in the mass range
100-190 GeV. The first phase of the Run 2 Higgs search, with a total integrated
luminosity of 2 fb-1 per detector, will provide a 95% CL exclusion sensitivity
comparable to that expected at the end of the LEP2 run. With 10 fb-1 per
detector, this exclusion will extend up to Higgs masses of 180 GeV, and a
tantalizing 3 sigma effect will be visible if the Higgs mass lies below 125
GeV. With 25 fb-1 of integrated luminosity per detector, evidence for SM Higgs
production at the 3 sigma level is possible for Higgs masses up to 180 GeV.
However, the discovery reach is much less impressive for achieving a 5 sigma
Higgs boson signal. Even with 30 fb-1 per detector, only Higgs bosons with
masses up to about 130 GeV can be detected with 5 sigma significance. These
results can also be re-interpreted in the MSSM framework and yield the required
luminosities to discover at least one Higgs boson of the MSSM Higgs sector.
With 5-10 fb-1 of data per detector, it will be possible to exclude at 95% CL
nearly the entire MSSM Higgs parameter space, whereas 20-30 fb-1 is required to
obtain a 5 sigma Higgs discovery over a significant portion of the parameter
space. Moreover, in one interesting region of the MSSM parameter space (at
large tan(beta)), the associated production of a Higgs boson and a b b-bar pair
is significantly enhanced and provides potential for discovering a non-SM-like
Higgs boson in Run 2.Comment: 185 pages, 124 figures, 55 table
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