An experiment investigating the photoelectron instability has been performed in BEPC at IHEP, China. The betatron oscillation of each bunch was observed and recorded by a single pass beam position monitor system which has a capability to measure the transverse position of every bunch over 16000 turns. The effect of an octupole magnet on the instability was also studied. This paper describes res...

In this article, I define you-are-here (YAH) maps and consider their fundamental characteristics from cartographic and psychological perspectives. I then review the basic phenomenon of the alignment effect, including why it happens and how it may be overcome; I also consider exceptions to the alignment effect. Finally, I briefly note some special issues with YAH maps that arise when a person us...

Single-color illumination of a copper surface by a red or an ultraviolet femtosecond laser pulse yields a threephoton (red) or a two-photon (UV) photoemission process. A multicolor, multiphoton process is generated when the red and the UV pulses overlap both in space and in time on the photocathode. It is shown that this emission process results from the absorption by an electron of one red and...