• Y. Polsky, P.J. Geoghegan, L.L. Jacobs, S.M. McTeer, M.A. Plum
  ORNL, Oak Ridge, Tennessee
• W. Lu
  ORNL RAD, Oak Ridge, Tennessee

The use of a beam stop to absorb full or partial beam at various points along a particle accelerator is commonplace. The design of accelerator components such as magnets, linacs and beam instruments tends to be a fairly focused and collective effort within the particle accelerator community with well established performance and reliability criteria. Beam stop design by contrast has been relatively isolated and unconstrained historically with much more general goals. This combination of conditions has lead to a variety of facility implementations with virtually no standardization and minimal concensus on approach to development within the particle accelerator community. At the Spallation Neutron Source (SNS), for example, there are four high power beam stops in use, three of which have significantly different design solutions. This paper describes the design of a new off-momentum beam stop for the SNS. Content will be balanced between hardware description, analyses performed and the methodology used during the development effort. Particular attention will be paid to the approach of the design process with respect to future efforts to meet beam stop performance metrics.

• I.I. Popova, P.D. Ferguson, F. X. Gallmeier, E. Iverson
  ORNL, Oak Ridge, Tennessee
• W. Lu
  ORNL RAD, Oak Ridge, Tennessee

All stages of the SNS development require significant research and development work in the field of radiological shielding design to assure safety from a radiation-protection point of view for facility operation and to optimize accelerator and target performance. Here we present an overview of on-going shielding work and associated with it procedures and regulations. In the present time, the most of the shielding work is focused on the neutron beam lines and their instrument enclosures in order to commission and provide save operation in the future. This effort is performed according to the guidelines for shielding calculations of SNS neutron beam lines, which sets standards for the analyses and helps to prepare for the Instrument Readiness Review (IRR). The IRR ascertains that the instruments has been design, constructed, and installed to allow safe operation and maintenance. In addition, there is still support for the accelerator facility to redesign parts of the accelerator structures, to design shielding for removed components and test stands for accelerator structures, and for radiation protection analyses for evaluations of accelerator and target safety systems.