- By:
- Lu, Wei ; Gallmeier, Franz X; Ferguson, Phillip D; Iverson, Erik B; Popova, Irina I
- Page Number:
- 203-211
- Book Title:
- Proceedings of Tenth International Topical Meeting on Nuclear Applications of Accelerators (AccApp'11)
- Publication Date:
- August 11, 2026
- Conference Name:
- Tenth International Topical Meeting on Nuclear Applications of Accelerators (AccApp'11)
- Conference Location:
- Knoxville, Tennessee, United States of America
- Conference Sponsor:
- Oak Ridge National Laboratory
Abstract
The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory reached a nominal operating power of 1 MW in September, 2009. Even at ~2/3 of its designed capacity, SNS already becomes the brightest pulsed neutron source in the world, and a premier facility for material and life science research. To provide accurate target performance estimation and to meet future development needs, we had developed an as-built model for the operating target system of SNS. Based on this asbuilt model, the moderator performance at SNS was recalculated taking advantage of the improved physics and tallying method in the Monte Carlo simulation code, MCNPX, and most recent scattering kernels. The neutron flux intensity spectra, emission time distributions of neutron pulses and moderator brightness profiles regarding the SNS moderator performance are presented and discussed. Compared to the previous results, the current calculations show ~10-20% lower in flux with improved emission time distributions of neutron pulses. The difference between the two data sets is analyzed, as well as other factors impacting the moderator performance at SNS. The current calculation results will serve as source terms for the instrument performance simulations at SNS.
