Abstracts Brochure - CERN

MOPCH — Poster Session 26-Jun-06 16:00 - 18:00
Initial Experience Tuning the SNS Superconducting Linac
The Spallation Neutron Source (SNS) accelerator
includes a pulsed superconducting linac
that accelerates H − from 186 MeV to 1000
MeV. The initial experience in setting the 81
J. Galambos, A.V. Aleksandrov, C. Deibele, S. Henderson, D.-O.
Jeon, T.A. Pelaia, Y. Zhang (ORNL)
independently powered cavities comprising the SCL is discussed. A model based time-of-flight method is used to
determine the cavity phase setpoints, the actual cavity voltages and beam output energy for each cavity. As the
cavities are turned on and set to the proper phase, different quadrupole settings are periodically loaded to facilitate
transport of the increasing energy beam. The SCL is quite flexible to running with various numbers of missing cavities
and operating cavities at different amplituides. Lattice configurations have been generated with final beam energies
ranging from 550 to 950 MeV.
Status of the SNS Beam Power Upgrade Project
The baseline Spallation Neutron Source
(SNS) accelerator complex, consisting of an
H − injector, a 1 GeV linear accelerator, an
accumulator ring and associated transport
lines, will provide a 1 GeV, 1.44 MW proton
beam to a liquid mercury target for neutron
production. Upgrades to the SNS accelerator
and target systems to increase the beam
S. Henderson, A.V. Aleksandrov, D.E. Anderson, S. Assadi, I.E.
Campisi, F. Casagrande, M.S. Champion, R.I. Cutler, V.V. Danilov,
G.W. Dodson, D.A. Everitt, J. Galambos, J.R. Haines, J.A. Holmes,
N. Holtkamp, T. Hunter, D.-O. Jeon, S.-H. Kim, D.C. Lousteau, T.L.
Mann, M.P. McCarthy, T. McManamy, G.R. Murdoch, M.A. Plum,
B.R. Riemer, M.P. Stockli, D. Stout, R.F. Welton (ORNL)
power to at least 2 MW, with a design goal of 3 MW, are in the planning stages. The increased SNS beam power
can be achieved primarily by increasing the peak H − ion source current from 38 mA to 59 mA, installing additional
superconducting cryomodules to increase the final linac beam energy to 1.3 GeV, and modifying injection and extraction
hardware in the ring to handle the increased beam energy. The mercury target power handling capability
will be increased to 2 MW or greater by i) mitigating cavitation damage to the target container through improved
materials/surface treatments, and introducing a fine dispersion of gas bubbles in the mercury, and ii) upgrading the
proton beam window, inner reflector plug and moderators. The upgrade beam parameters will be presented and the
required hardware modifications will be described.
Simulations for SNS Ring Commissioning
In preparation for SNS ring commissioning, a
number of operational issues have been stud- J.A. Holmes, S.M. Cousineau, S. Henderson, M.A. Plum (ORNL)
ied using ORBIT Code simulations. These
include beam injection without the use of time-dependent painting, beam accumulation and transport to the extraction
dump and to the target, optimal painting schemes for various beam intensities, detailed tracking through
the extraction septum with fully correct geometry, quadrupole current constraints in the ring-to-target transfer line
(RTBT), and detailed modeling of H minus carbon foil stripping at injection. All these studies incorporated detailed
physics including beam-foil interactions, symplectic single particle tracking, space charge and impedances, and losses
due to apertures and collimation.
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