Negative KERMA xs

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MohammedQah
Posts: 10
Joined: Wed Mar 29, 2017 2:06 am
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Negative KERMA xs

Post by MohammedQah » Thu Oct 10, 2019 6:59 pm

I previously ignored this from the code to calculate the energy deposition :

lines 419-422:
else
Die(FUNCTION_NAME, "Mismatch in lowest energy of ACE and KERMA datas "
"for nuclide %s (mt=%ld) \nACE: %.20E KERMA: %.20E",
GetText(nuc + NUCLIDE_PTR_NAME), mt, E[0], E0[0]);

lines 426-429:
else
Die(FUNCTION_NAME, "Mismatch in highest energy of ACE and KERMA datas "
"for nuclide %s (mt=%ld) \nACE: %.20E KERMA: %.20E",
GetText(nuc + NUCLIDE_PTR_NAME), mt, E[NES - 1], E0[np - 1]);


However, lots of messages show "negative xs points in KERMA data" :

***** Thu Oct 10 11:33:01 2019 (seed = 1570721567335)
Warning message from function ReadPendfData:

1295 negative xs points in KERMA data (42092.03c)

Nuclide 42092.03c -- molybdenum 92 at 300K (Mo-92)

***** Thu Oct 10 11:33:01 2019 (seed = 1570721567335)
Warning message from function ReadPendfData:

1597 negative xs points in KERMA data (42094.03c)

Nuclide 42094.03c -- molybdenum 94 at 300K (Mo-94)
Nuclide 42095.03c -- molybdenum 95 at 300K (Mo-95)

***** Thu Oct 10 11:33:01 2019 (seed = 1570721567335)
Warning message from function ReadPendfData:

1848 negative xs points in KERMA data (42096.03c)

Nuclide 42096.03c -- molybdenum 96 at 300K (Mo-96)

***** Thu Oct 10 11:33:02 2019 (seed = 1570721567335)
Warning message from function ReadPendfData:

1112 negative xs points in KERMA data (42097.03c)

Nuclide 42097.03c -- molybdenum 97 at 300K (Mo-97)

***** Thu Oct 10 11:33:02 2019 (seed = 1570721567335)
Warning message from function ReadPendfData:

1597 negative xs points in KERMA data (42098.03c)

Nuclide 42098.03c -- molybdenum 98 at 300K (Mo-98)
Nuclide 42099.03c -- molybdenum 99 at 300K (Mo-99)
Nuclide 42100.03c -- molybdenum 100 at 300K (Mo-100)



The question is, How can I see the differences in the energy deposition between (1) with negative KERMA, and (2) with zero KERMA.

Or does the code consider the negative KERMA as zero?

Riku Tuominen
Posts: 63
Joined: Tue Feb 27, 2018 10:52 am
Security question 1: No
Security question 2: 93

Re: Negative KERMA xs

Post by Riku Tuominen » Fri Oct 11, 2019 3:29 pm

Hi! Serpent does not reset negative KERMA values to zero. In order to do this, you can do the following modification in processxsdata.c:

Lines 480-482

Before:
if (mt == 301)
n = InterpolateData(&WDB[pte], xs, ne, &XSS[L0 + I0],
&XSS[L1], NES, 0, &dum1, &dum2, YES);

After:
if (mt == 301)
n = InterpolateData(&WDB[pte], xs, ne, &XSS[L0 + I0],
&XSS[L1], NES, 0, &dum1, &dum2, NO);

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