crp/OpenMC
1
0
Fork 0
mirror of https://github.com/openmc-dev/openmc.git synced 2026-07-26 21:25:36 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions

Merge pull request #3 from paulromano/photon-alund

Browse source 
Fix bug in Doppler energy broadening for Compton scattering
This commit is contained in:
Amanda Lund 2018-03-21 12:25:15 -07:00 • committed by GitHub
commit e9bd7a203e
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
1 changed files with 11 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

14
src/photon_physics.F90
View file

@ -155,8 +155,8 @@ contains
! Sample electron shell
rn = prn()
c = ZERO
do i_shell = 1, size(el % electron_pdf) - 1
c = c + el % electron_pdf(i_shell + 1)
do i_shell = 1, size(el % electron_pdf)
c = c + el % electron_pdf(i_shell)
if (rn < c) exit
end do
@ -217,6 +217,7 @@ contains
end if
! Determine outgoing photon energy corresponding to electron momentum
! (solve Eq. 39 in LA-UR-04-0487 for E')
momentum_sq = (pz/FINE_STRUCTURE)**2
f = ONE + alpha*(ONE - mu)
a = momentum_sq - f*f
@ -232,8 +233,10 @@ contains
e_out1 = -(b + quad)/(TWO*a)
e_out2 = -(b - quad)/(TWO*a)
! Determine solution to quadratic equation that is positive
if (e_out1 > ZERO) then
if (e_out2 > ZERO) then
! If both are positive, pick one at random
if (prn() < HALF) then
e_out = e_out1
else
@ -243,7 +246,12 @@ contains
e_out = e_out1
end if
else
if (e_out2 > ZERO) e_out = e_out2
if (e_out2 > ZERO) then
e_out = e_out2
else
! No positive solution -- resample
cycle
end if
end if
if (e_out < e - e_b) exit
end do