ENDF/B-VIII.1 photonuclear data for U-233

[anl333]

Hello,

I used tests 56-58 to process the photonuclear data of U-233 from ENDF/B-VIII.1 library and I do not see the Giant Dipole Resonance for alpha production, is it normal?

Thanks,
Al

'<U233 from ENDF/B-VIII.1 photonuclear data - check tape 1>'/
'

article production cross sections'/
alphas
'nergy (e)'/
'ross section (barns)'/
1.000000E+00 0.000000E+00/
1.500000E+00 4.208744E-22/
2.000000E+00 1.898175E-20/
2.500000E+00 5.760621E-19/
3.000000E+00 1.202374E-17/
3.500000E+00 1.786944E-16/
4.000000E+00 1.959140E-15/
4.500000E+00 1.521554E-14/
5.000000E+00 1.722024E-13/
5.250000E+00 3.981413E-13/
5.500000E+00 4.006932E-13/
5.750000E+00 1.913400E-13/
6.000000E+00 2.259736E-13/
6.500000E+00 9.529574E-13/
7.000000E+00 5.325231E-12/
7.500000E+00 2.603037E-11/
8.000000E+00 1.131175E-10/
8.500000E+00 2.937752E-10/
9.000000E+00 5.774474E-10/
9.500000E+00 1.245995E-09/
1.000000E+01 2.682307E-09/
1.050000E+01 5.394259E-09/
1.100000E+01 9.457313E-09/
1.150000E+01 1.421925E-08/
1.200000E+01 1.948438E-08/
1.250000E+01 2.888970E-08/
1.300000E+01 4.929926E-08/
1.350000E+01 9.363621E-08/
1.400000E+01 1.835541E-07/
1.450000E+01 3.494100E-07/
1.500000E+01 6.284334E-07/
1.550000E+01 1.047692E-06/
1.600000E+01 1.717468E-06/
1.650000E+01 2.738492E-06/
1.700000E+01 4.173674E-06/
1.750000E+01 6.335527E-06/
1.800000E+01 8.914064E-06/
1.850000E+01 1.240166E-05/
1.900000E+01 1.641771E-05/
1.950000E+01 2.112147E-05/
2.000000E+01 2.642786E-05/
2.100000E+01 3.763332E-05/
2.200000E+01 4.945500E-05/
2.300000E+01 6.124991E-05/
2.400000E+01 7.224035E-05/
2.500000E+01 8.269210E-05/
2.600000E+01 9.246658E-05/
2.700000E+01 1.012154E-04/
2.800000E+01 1.093277E-04/
2.900000E+01 1.166073E-04/
3.000000E+01 1.234830E-04/
3.200000E+01 1.375299E-04/
3.400000E+01 1.496148E-04/
3.600000E+01 1.614092E-04/
3.800000E+01 1.735747E-04/
4.000000E+01 1.863462E-04/
4.200000E+01 1.998402E-04/
4.400000E+01 2.141169E-04/
4.600000E+01 2.293517E-04/
4.800000E+01 2.449007E-04/
5.000000E+01 2.612065E-04/
5.200000E+01 2.773244E-04/
5.400000E+01 2.944865E-04/
5.600000E+01 3.117721E-04/
5.800000E+01 3.294493E-04/
6.000000E+01 3.475103E-04/
6.200000E+01 3.648167E-04/
6.400000E+01 3.832407E-04/
6.600000E+01 4.012079E-04/
6.800000E+01 4.192286E-04/
7.000000E+01 4.374814E-04/
7.200000E+01 4.547354E-04/
7.400000E+01 4.733459E-04/
7.600000E+01 4.921455E-04/
7.800000E+01 5.101732E-04/
8.000000E+01 5.291996E-04/
8.500000E+01 5.761421E-04/
9.000000E+01 6.241064E-04/
9.500000E+01 6.736173E-04/
1.000000E+02 7.239764E-04/
1.100000E+02 8.277368E-04/
1.200000E+02 9.443711E-04/
1.300000E+02 1.060567E-03/
1.400000E+02 1.198238E-03/
1.500000E+02 1.304451E-03/
1.600000E+02 1.417058E-03/
1.700000E+02 1.521348E-03/
1.800000E+02 1.626029E-03/
1.900000E+02 1.725311E-03/
2.000000E+02 1.817820E-03/

[akhatiwa]

This is expected. The ENDF/B-VIII.1 photonuclear library for U-233 does not include MT=107 (the explicit alpha production) reaction in MF=3. NJOY constructs particle production cross sections by summing over all reactions that emit alpha particles using MF=6. The alpha production cross section you are seeing in the output is this cross section. The reason this remains pretty small and smooth is because of Coulomb barrier. For alpha emission in heavy nuclei this is around 25 MeV well above the GDR peak around 10-20 MeV. So, you do not expect to see a pronounced GDR shape.