The delayed hard (up to 25 GeV) photons observed more than an hour following a gamma-ray burst on February 17, 1994 may result from the collisions of relativistic nucleons with a dense cloud, producing π 0. The required cloud density is ∼ 2 × 10 11 cm −3. This cloud may be the remains of the disrupted envelope of a neutron star, and may survive as an excretion disc of ∼ 10 14 –10 15 cm radius a...

We report the formation of dinuclear complexes from, and photochemical oxidation of, (CH3)3-Pt(IV)(N^N) (N^N = 1,2-diimine derivatives) thiophenolate ligands to analogous sulfinates (CH3)3Pt(N^N)(SO2Ph) structural, spectroscopic, theoretical studies latter revealing tunable photophysics depending upon ligands. Electron-rich thiolate conjugated 1,2-diimines encourage thiolate-bridged complexes; ...

The interference of stray electrons (also called ‘‘electron clouds’’) with accelerator beams is important in modern intense-beam accelerators, especially those with beams of positive charge. In magnetic wigglers, used, for instance, for transverse emittance damping, the intense synchrotron radiation produced by the beam can generate an electron cloud of relatively high density. In this paper th...

A positron be additional focusing is g cloud densities. This pa Linear Collider Collaboration Tech Notes Single Bunch Electron Cloud Effects in the NLC Beam Delivery System David Chen, Arthur Chang, M. T. F. Pivi, T. O. Raubenheimer Stanford Linear Accelerator Center Stanford University Stanford, CA am passing through a linear collider beam delivery line is finely focused to desired specificati...

In positron storage rings electrons produced by photoemission, ionization and secondary emission accumulate in the vacuum chamber and form an ”electron cloud ” which can reach a high charge density for some beam operation modes. Electron cloud effects have not been observed in the present operation mode of the PETRA II ring used as a preaccelerator for HERA, but with the high performance goals ...

This conference paper presents a series of electron cloud measurements in the Fermilab Main Injector and Recycler. A new instability was observed in the Recycler in July 2014 that generates a fast transverse excitation in the first high intensity batch to be injected. Microwave measurements of electron cloud in the Recycler show a corresponding dependence on the batch injection pattern. These e...