Author: Reiss, T.
Paper Title Page
THPWO083 Simulation of a Beam Rotation System for the SINQ Spallation Source at PSI 3954
  • D. Reggiani, T. Reiss, M. Seidel, V. Talanov, M. Wohlmuther
    PSI, Villigen PSI, Switzerland
  With a nominal beam power of nearly 1 MW on target, the PSI-SINQ ranks among the world's most powerful neutron spallation sources. The proton beam transport to the SINQ target is carried out exclusively by means of linear elements. As a consequence, at the SINQ target entrance the beam presents Gaussian transverse x and y distributions with tails cut short by collimators. This leads to a highly uneven temperature distribution inside the SINQ zircaloy target, giving rise to thermal and mechanical stress. In view of a future beam intensity upgrade, the possibility of homogenizing the beam distribution by means of a fast beam rotation system is currently under study. Important aspects of this method concern the resulting neutron spectrum and flux distribution. The simulations of the beam distribution achievable thanks to this technique as well as its consequences in terms of neutron production are presented in this contribution.  
THPWO084 Optimization of a Bi-spectral Boxed Side-by-Side Moderator for the Target-Moderator-Reflector System of the ESS 3957
  • T. Reiss, U. Filges, V. Talanov, M. Wohlmuther
    PSI, Villigen PSI, Switzerland
  • F. X. Gallmeier
    ORNL, Oak Ridge, Tennessee, USA
  Providing bi-spectral neutron beams is one of the main neutronics design criteria for the target-moderator-reflector (TMR) system of the European Spallation Source, to be built in Lund (Sweden). As a first step, the requirements of neutronics instruments regarding the neutron spectrum are formulated, a figure of merit is defined. In order to maximize the moderator performance to obtain bi-spectral neutron extraction, a parametrized model of the TMR system is developed and used with a MCNPX-based optimization framework. This model is then used to study and optimize the moderator performance, especially in the thermal and cold parts of the spectrum. Results obtained with an optimized moderator setup are dicussed and compared with the requirements of the instruments.