Inverse patchy colloids (IPC's) have recently been introduced as a conceptually simple model to study the phase-behavior of heterogeneously charged units. This class of patchy particles is referred ...to as inverse to highlight that the patches repel each other in contrast to the attractive interactions of conventional patches. IPCs demonstrate a complex interplay between attractions and repulsions that depend on their patch size and charge, their relative orientations as well as on charge of the substrate below; the resulting wide array of different types of aggregates that can be formed motivates their fabrication and use as model system. We present a novel method that does not rely on clean-room facilities and that is easily scalable to modify the surface of colloidal particles to create two polar regions with the opposite charge with respect to that of the equatorial region. The patch size is characterized by electron microscopy and fluorescently labeled to facilitate using confocal microscopy to study their phase behavior. We show that the pH can be used to tune the charges of the IPCs thus offering a tool to steer the self assembly.
This report describes the three polarimeters which will be used to measure the beam polarization at the AGS polarized beam facility. The beam polarization will be measured before injection into the ...AGS, during acceleration, and after extraction from the AGS. The 200 MeV polarimeter uses scintillation counter telescopes to measure the asymmetry in p-carbon inclusive scattering. The internal polarimeter can measure the beam polarization at up to five selected times during acceleration. A continuously spooled nylon filament is swung into the beam at the appropriate time and the asymmetry in pp elastic scattering measured by two scintillation counter telescopes. This is a relative polarimeter which can be calibrated by the absolute external polarimeter located in the "D" extracted beam line. This polarimeter uses scintillation counters in two double-arm magnetic spectrometers to measure clearly the asymmetry in pp elastic scattering from a liquid hydrogen target. The specific features and operation of each polarimeter will be discussed.
Leptonic branching ratio of the ϒ ( 2 S ) Hass, P.; Jensen, T.; Kagan, H. ...
Physical review. D, Particles and fields,
11/1984, Letnik:
30, Številka:
9
Journal Article
PDF
