As the energy recovery transport must provide large momentum acceptance, we have studied the chromatic performance of the system in some detail. The first of the following figures presents the results of a momentum scan at the wiggler of the cryomodule to wiggler transport beam envelope and orbit functions; the second of the following figures presents similar results at the reinjection point for the wiggler to reinjection transport. The system behavior is acceptable; no beam loss is anticipated. We do observe a significant variation of phase advance with momentum; as this is a single pass system this is not a serious problem, although it can give rise to phase space distortions in certain cases, as we shall see in subsequent discussions of system behavior during energy recovery.

The next figures provide momentum scan results for horizontal (the first figure) and vertical (the second figure) beam envelopes throughout the wiggler to reinjection transport. Therein we see the chromatic behavior of the beam envelopes plotted as a function of position through the system and note again that no untoward chromatic variations are observed. As one may infer from the previous graphs, worst-case variations yield peak beam envelopes of ~35 m, a factors of two to three times the nominal peak of order 13 m.

Last modified: 10 March 1997
http://www.jlab.org/~douglas/ is maintained by: douglas@jlab.org