LANL, Los Alamos, New Mexico
TechSource, Santa Fe, New Mexico
Recent beam studies have focused on understanding the main sources and locations of electron clouds (EC) which drive the observed e-p instability at the PSR. New results using a recently developed electron diagnostic will be reported which demonstrate the important role of EC activity in quadrupole magnets, including definitive evidence that ~80% or more of the drift space EC signal is “seeded” by electrons ejected by ExB drifts from adjacent quadrupole magnets*. Other observations include distinctive brown colored tracking in various dipole and quadrupole vacuum chambers, which we hypothesize is caused by energetic electrons striking the wall during beam-induced multipacting. The tracking observations point to a simple and useful signature for regions of EC activity. Modeling of EC observations using a modified version of the POSINST** code shows general agreement on many features of the observations, given the large uncertainties in the distribution of seed electrons from beam loss which is a key input into the simulations. Progress will be reported on resolving the features not in agreement.
* R. Macek et al, PRSTAB, 11, 010101 (2008).
** M. T. F. Pivi and M. A. Furman, PRSTAB, 6, 034201 (2003).
LANL, Los Alamos, New Mexico
The heart of the Los Alamos Neutron Science Center (LANSCE) is a pulsed linear accelerator that is used to simultaneously provide H+ and H- beams to several user facilities. This accelerator contains two Cockcroft-Walton style injectors, a 100-MeV drift tube linac and an 800-MeV coupled cavity linac. This presentation will touch on various aspects of the high power operation including performance and limitations, tune-up strategy, beam losses and machine protection.
LANL, Los Alamos, New Mexico
We are developing a compact deuteron-beam accelerator up to the energy of a few MeV based on room-temperature inter-digital H-mode (IH) accelerating structures with the transverse beam focusing using permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we show that IH-PMQ structures provide very efficient and practical accelerators for light-ion beams of considerable currents at the beam velocities around a few percent of the speed of light. IH-structures with PMQ focusing following a short RFQ can also be beneficial in the front end of ion linacs.