Reich-Moore Resonances

The Reich-Moore resonance representation (pronounced like "Rich-More") can handle both multi-level and multi-channel effects with good fidelity. No background corrections in File 3 are needed. Methods are now becoming available (the "multi-pole expansion") to allow analytic Doppler broadening and the direct use of Reich-Moore parameters in analytic reactor-physics methods. The Reich-Moore approach is used by the resonance analysis code SAMMY from ORNL, which is the current state of the art. Because of these factors, it has become the dominant choice for many of the new evaluations in ENDF/B-VI, including both fissionable isotopes with two fission channels like U-235, and nonfissionable materials like iron, copper, and lead.

      9.223501+4 2.330250+2          0          0          1          09228 2151
      9.223501+4 1.000000+0          0          1         12          09228 2151
      1.000000-5 4.000000+0          1          3          0          09228 2151
      3.500000+0 9.859600-1          0          0          1          39228 2151
      2.330200+2 9.859600-1          0          0        138         239228 2151
     -1.000000+2 3.000000+0 1.145800-2 3.871290-2 1.229980-4 7.233640-29228 2151
     -9.000000+1 4.000000+0 2.422100-6 3.680760-2 5.617020-2-2.168940-19228 2151
     -4.297600+0 4.000000+0 7.164100-3 3.481860-2 3.192990-1-1.153500-19228 2151
     -3.493400+0 3.000000+0 8.471500-8 3.780160-2-6.760010-3 1.298560-29228 2151
     -1.504300+0 3.000000+0 8.519600-8 3.767610-2-7.010690-3 1.232090-29228 2151
     -4.116100-1 3.000000+0 1.487500-4 2.984470-2-1.027260-3-1.554150-19228 2151
     -1.942800-1 4.000000+0 5.044600-7 3.504170-2 1.989540-1-1.694210-39228 2151
      3.657500-5 4.000000+0 6.50520-11 2.984470-2-5.263430-4 9.645560-49228 2151
      2.819000-1 3.000000+0 4.439200-6 3.837130-2 1.065400-1-4.849860-39228 2151
      1.138900+0 4.000000+0 1.384200-5 4.069500-2-4.640000-6 1.093200-19228 2151
      2.036100+0 3.000000+0 9.358700-6 3.933000-2-7.736600-3-1.573500-39228 2151
      2.776700+0 4.000000+0 1.277200-6 3.887600-2 6.049200-2-4.250300-29228 2151
      3.156600+0 3.000000+0 2.432600-5 3.989600-2-7.995100-2 1.716100-29228 2151
      3.620800+0 4.000000+0 4.184000-5 3.764400-2-2.679600-2 2.849100-29228 2151
      4.850800+0 4.000000+0 7.560500-5 3.801700-2 4.666800-5-3.735100-39228 2151
      5.449700+0 4.000000+0 3.793200-5 3.920100-2-7.874000-2-3.612500-19228 2151
      6.209400+0 3.000000+0 1.654700-4 4.005100-2-1.079400-1 7.385900-29228 2151
      ...

In this case, the energy range being described is 1e-5 to 4.0 eV (other ranges are also given for higher energies up to 2.25 keV). The target spin is 3.5, and the scattering length of .98596 translates to a potential scattering cross section of 12.216 barns. The columns give resonance energy, J value, Γ_N, Γ_γ, Γ_FA, and Γ_FB. The existence of two fission widths is part of the explanation for the great fidelity the the Reich-Moore fit to the experimental data for U-235. There is only one l value, l=0, for this case.

INDEX

15 December 2012

T-2 Nuclear Information Service

ryxm@lanl.gov