0000000000505231

AUTHOR

J. Gröbner

Determining the infrared radiative effects of Saharan dust: a radiative transfer modelling study based on vertically resolved measurements at Lampedusa

Detailed measurements of radiation, atmospheric and aerosol properties were carried out in summer 2013 during the Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region (ADRIMED) campaign in the framework of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx) experiment. This study focusses on the characterization of infrared (IR) optical properties and direct radiative effects of mineral dust, based on three vertical profiles of atmospheric and aerosol properties and IR broadband and narrowband radiation from airborne measurements, made in conjunction with radiosonde and ground-based observations at Lampedusa, in the central Mediterranean. Satellite IR spe…

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A single trapped antiproton and antiprotons for antihydrogen production

During the last several years, our TRAP collaboration has pioneered techniques for slowing, trapping, cooling and indefinitely storing antiprotons to energies more than 1010 times lower than previously possible. The radio signal from a single trapped antiproton is now being used for precision measurements. Many cold antiprotons are “stacked” as another important step toward the eventual production of antihydrogen, and positrons have been trapped in vacuum.

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Precision mass measurements of antiprotons in a Penning trap

Utilizing electron cooling, the TRAP collaboration has lowered the energy at which antiprotons can be stored and studied by more than 10 orders of magnitude, starting with 6 MeV particles from LEAR. We have held cryogenic antiprotons a few degrees above absolute zero for two months and the storage lifetime so established, more than 3.4 months is the longest directly measured limit for antiprotons. Measuring their cyclotron frequencies in a precision cylindrical Penning trap, we have shown that the inertial masses of the antiprotons and protons are the same to a fractional accuracy of 4 parts in 108, a 1000-fold improvement over the previous comparisons. This is the most stringent test of CP…

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Extremely cold antiprotons for antihydrogen production

The possibility to produce, trap and study antihydrogen atoms rests upon the recent availability of extremely cold antiprotons in a Penning trap. Over the last five years, our TRAP Collaboration has slowed, cooled and stored antiprotons at energies 1010 lower than was previously possible. The storage time exceeds 3.4 months despite the extremely low energy, which corresponds to 4.2 K in temperature units. The first example of measurements which become possible with extremely cold antiprotons is a comparison of the antiproton inertial masses which shows they are the same to a fractional accuracy of 4×10−8. (This is 1000 times more accurate than previous comparisons and large additional incre…

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Observing a single trapped antiproton

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