ismooth operations on MT5 secondary energy distributions

jchsublet commented 5 years ago

MT5 is essentially a change in how reactions are disentangled: starting at an incident energy of 20 or 30 MeV, all reactions are lumped together into a single reaction with multiplicities and secondary distributions.

The smooth operation will add a sqrt(E) tail to the lower energy part of the secondary distribution up to the threshold energy of the reaction. This is justified for the explicit reactions (MT2, MT51, etc). Since MT5 requires to be defined starting at 1e-5 eV, it does not seem necessary to extend the secondary distributions this low for incident particles with energies above 20 or 30 MeV. The evaluator already has to cut off the distribution anyway.

It may be a good idea to exclude MT5 from automatic ismooth operations. This is @kahlerac 's upn piece to achieve this:

*ident up148
*/ 22jul2019
*/   - acer/acefc
*/     - modify use of ismooth ... turn it off when processing
*/       mt=5 regardless of original ismooth setting.
*i up118.16
   !               NOTE:  The ismooth option is turned off when
   !                      processing mt=5, regardless of user input!
*i acefc.6790
   integer::ismoo
*i acefc.7145
      ! turn off ismooth when mt=5
      ismoo=ismooth
      if (mt.eq.5)ismoo=0
*d acefc.7171
            ! do NOT perform this operation when mt=5
            if (ismoo.gt.0.and.law.eq.1.and.lang.eq.2.and.&
*d acefc.7211
            ! do NOT perform this operation when mt=5
            else if (ismoo.gt.0.and.law.eq.1.and.lang.eq.2.and.&
*ident up148m
*/ 22jul2019
*/   - no manual changes.
*ident up149
*/ 22jul2019
*/   - groupr
*/     - modify use of ismooth ... turn it off when processing
*/       mt=5 regardless of original ismooth setting.
*i up117.18
   !            NOTE:  The ismooth option is turned off when
   !                   processing mt=5, regardless of user input!
*i groupr.5662
   integer::ismoo
*i groupr.5794
      ! turn off ismooth if mt=5
      ismoo=ismooth
      if (mtd.eq.5) ismoo=0
*d groupr.5830
         if (ismoo.gt.0.and.jzap.eq.1.and.lep.eq.1) then
*d groupr.5873
         elseif (ismoo.gt.0.and.jzap.eq.1.and.lep.eq.2) then

jlconlin commented 5 years ago

I guess I'm not sure what you are suggesting here. Is this simply to exclude MT=5 from being smoothed?

whaeck commented 5 years ago

@jlconlin Yes, this would just exclude MT5 from ismooth.

I suggest we add an option to allow users to switch it on again.

jchsublet commented 5 years ago

This option would need to be set by default to ismoo=0 for mt=5 MT=5 correspond to (z,anything), with each particle identified with multiplicity and spectra given in file 6. As its Q value is set to 0.0, secondary would need to extend to 1e-05 eV, although it has a threshold, 20 or 30 MeV when used as a format transition framework

njoy / NJOY2016

ismooth operations on MT5 secondary energy distributions #131