Why Are MCNP Photons Getting Lost?

[MadGander]

Hello,

I've been running into some frustrating issues with my MCNP deck. Photons are getting lost which is terminating the run file prematurely. When consulting the output file there seems to be some sort of geometry issue, but there are no fatal errors that I can see so I'm lost on how to resolve this problem. Any help is appreciated. The deck is listed below.

c cell card
1 1 -14.36 -1 imp:p 1     $ sample
2 2 -1.43 -2 1 imp:p 1     $ Kapton tape
3 2 -1.43 -3 imp:p 1
4 2 -1.43 -4 imp:p 1
5 2 -1.43 -5 imp:p 1
6 2 -1.43 -6 imp:p 1
7 4 -1 -7 imp:p 1     $ Scotch tape
8 0 -8 imp:p 1     $ tally cells
9 0 -9 imp:p 1
10 0 -10 imp:p 1
11 0 -11 imp:p 1
12 0 -12 imp:p 1
13 0 -13 imp:p 1
14 0 -14 imp:p 1
15 0 -15 imp:p 1
16 0 -16 imp:p 1
17 0 -17 imp:p 1
18 0 -18 imp:p 1
19 0 -19 imp:p 1
20 0 -20 imp:p 1
21 0 -21 imp:p 1
22 0 -22 imp:p 1
23 0 -23 imp:p 1
24 0 -24 imp:p 1
25 0 -25 imp:p 1
26 0 -26 imp:p 1
27 0 -27 imp:p 1
28 0 -28 imp:p 1
29 3 -0.001205 -29 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
     19 20 21 22 23 24 25 26 27 28 imp:p 1     $ bounding sphere
30 0 29 imp:p 0     $ graveyard

c surface card
1 RPP 33.02 33.1  -0.556 0.556  -0.556 0.556     $ sample 0.08 cm thick
2 RPP 33.017 33.103  -0.556 0.556  -0.556 0.556     $ Kapton tape 0.003 cm thick
3 RPP 33.1 33.103  -0.9525 0.9525  -0.953 -0.556     $ lower edge of kapton
4 RPP 33.1 33.103  -0.9525 0.9525  0.556 0.953     $ upper edge of kapton
5 RPP 33.1 33.103  -0.953 -0.556  -0.9525 0.9525     $ left edge of kapton
6 RPP 33.1 33.103  0.556 0.953  -0.9525 0.9525     $ right edge of kapton
7 RPP 33.0168 33.017  -3 3 -15 15     $ Scotch tape
8 RPP 58.42 59.42  -0.278 0.278  -0.278 0.278     $ center tally cell
9 RPP 58.42 59.42  0.278 0.556  0 0.278     $ center/right/top
10 RPP 58.42 59.42  0.278 0.556  -0.278 0     $ center/right/bottom
11 RPP 58.42 59.42  -0.556 -0.278  -0.278 0     $ center/left/bottom
12 RPP 58.42 59.42  -0.556 -0.278  0 0.278     $ center/left/top
13 RPP 58.42 59.42  0 0.278  0.278 0.556     $ center/top/right
14 RPP 58.42 59.42  -0.278 0  0.278 0.556     $ center/top/left
15 RPP 58.42 59.42  0 0.278  -0.556 -0.278     $ center/bottom/right
16 RPP 58.42 59.42  -0.278 0  -0.556 -0.278     $ center/bottom/left
17 RPP 58.42 59.42  0.278 0.556  0.278 0.556     $ center/northeast
18 RPP 58.42 59.42  0.278 0.556 -0.556 -0.278     $ center/southeast
19 RPP 58.42 59.42  -0.556 -0.278  0.278 0.556     $ center/northwest
20 RPP 58.42 59.42  -0.556 -0.278  -0.556 -0.278     $ center/southwest
21 RPP 58.42 59.42  -0.834 0.556  0.556 0.834     $ top off edge tally
22 RPP 58.42 59.42  0.556 0.834  -0.556 0.834     $ right off edge tally
23 RPP 58.42 59.42  -0.566 0.834  -0.834 -0.556     $ bottom off edge tally
24 RPP 58.42 59.42  -0.834 -0.556  -0.834 0.556     $ left off edge tally
25 RPP 58.42 59.42  -0.834 0.834  0.834 1.834     $ top open beam tally
26 RPP 58.42 59.42  -0.834 0.834  -1.834 -0.834     $ bottom open beam tally
27 RPP 58.42 59.42  0.834 1.834  -0.834 0.834     $ right open beam tally
28 RPP 58.42 59.42  -1.834 -0.834  -0.834 0.834     $ left open beam tally
29 SO 68

c data card
mode p
nps 1000000000
SDEF POS 0 0 0 PAR=P ERG=d1
SI1 H 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004 0.0045
     0.005 0.0055 0.006 0.0065 0.007 0.0075 0.008 0.0085
     0.009 0.0095 0.01 0.0105 0.011 0.0115 0.012 0.0125
     0.013 0.0135 0.014 0.0145 0.015 0.0155 0.016 0.0165
     0.017 0.0175 0.018 0.0185 0.019 0.0195 0.02 0.0205
     0.021 0.0215 0.022 0.0225 0.023 0.0235 0.024 0.0245
     0.025 0.0255 0.026 0.0265 0.027 0.0275 0.028 0.0285
     0.029 0.0295 0.03 0.0305 0.031 0.0315 0.032 0.0325
     0.033 0.0335 0.034 0.0345 0.035 0.0355 0.036 0.0365
     0.037 0.0375 0.038 0.0385 0.039 0.0395 0.04 0.0405
     0.041 0.0415 0.042 0.0425 0.043 0.0435 0.044 0.0445
     0.045 0.0455 0.046 0.0465 0.047 0.0475 0.048 0.0485
     0.049 0.0495 0.05 0.0505 0.051 0.0515 0.052 0.0525
     0.053 0.0535 0.054 0.0545 0.055 0.0555 0.056 0.0565
     0.057 0.0575 0.058 0.0585 0.059 0.0595 0.06 0.0605
     0.061 0.0615 0.062 0.0625 0.063 0.0635 0.064 0.0645
     0.065 0.0655 0.066 0.0665 0.067 0.0675 0.068 0.0685
     0.069 0.0695 0.07 0.0705 0.071 0.0715 0.072 0.0725
     0.073 0.0735 0.074 0.0745 0.075 0.0755 0.076 0.0765
     0.077 0.0775 0.078 0.0785 0.079 0.0795 0.08 0.0805
     0.081 0.0815 0.082 0.0825 0.083 0.0835 0.084 0.0845
     0.085 0.0855 0.086 0.0865 0.087 0.0875 0.088 0.0885
     0.089 0.0895 0.09 0.0905 0.091 0.0915 0.092 0.0925
     0.093 0.0935 0.094 0.0945 0.095 0.0955 0.096 0.0965
     0.097 0.0975 0.098 0.0985 0.099 0.0995 0.1
     $ histogram upper boundaries (200 energy bins)
SP1 D 0
     0
     5.11347E-06
     0.000121555
     3.08604E-05
     0
     0
     8.31027E-06
     8.7771E-05
     0.000359376
     0.000946079
     0.001877169
     0.003548272
     0.005150231
     0.006742632
     0.016790123
     0.014374974
     0.012801486
     0.024634899
     0.011637658
     0.015204991
     0.0107191
     0.008945965
     0.009214431
     0.015634477
     0.009179067
     0.009152242
     0.00943935
     0.010478518
     0.010235272
     0.010345676
     0.010531003
     0.010234591
     0.01073557
     0.010859254
     0.011212683
     0.011140717
     0.011089523
     0.010867856
     0.010987345
     0.011155824
     0.010809004
     0.011037909
     0.010752565
     0.010937409
     0.010729171
     0.010745011
     0.010583666
     0.010481057
     0.010277613
     0.010390617
     0.010158208
     0.010171552
     0.009960702
     0.010035846
     0.009819078
     0.009828614
     0.009517127
     0.009333436
     0.009406346
     0.009269727
     0.008867548
     0.008940091
     0.008521914
     0.008432146
     0.008507657
     0.008371625
     0.008354725
     0.00794921
     0.007963582
     0.007768016
     0.007666614
     0.00774671
     0.007514888
     0.007287714
     0.007189879
     0.007027001
     0.006843111
     0.006814986
     0.006970499
     0.006564386
     0.006477514
     0.006288494
     0.006329008
     0.006155955
     0.006046507
     0.005918102
     0.005944737
     0.00578743
     0.005658994
     0.00563903
     0.005555042
     0.005472806
     0.005113881
     0.005375275
     0.005027333
     0.005019937
     0.005089112
     0.004891952
     0.004766316
     0.004586465
     0.004527969
     0.004351737
     0.004400257
     0.004311621
     0.004322532
     0.004149311
     0.004076936
     0.003974694
     0.004101935
     0.003906201
     0.003932123
     0.003898879
     0.003951311
     0.003648835
     0.008549116
     0.003395487
     0.012448897
     0.003362305
     0.003395445
     0.003248954
     0.003229609
     0.003147635
     0.002916915
     0.002987517
     0.002910967
     0.002877974
     0.00273077
     0.002851213
     0.002961867
     0.002615342
     0.002670858
     0.002596836
     0.005511989
     0.002374152
     0.002347264
     0.002388104
     0.002970019
     0.002251517
     0.001893168
     0.001914275
     0.002046383
     0.001923139
     0.001900081
     0.00176021
     0.002097179
     0.001679893
     0.001536802
     0.001690877
     0.002112264
     0.001642358
     0.001356783
     0.00140141
     0.001483782
     0.001486027
     0.001390132
     0.001416076
     0.001205739
     0.001301917
     0.001234389
     0.001154041
     0.001219586
     0.00121325
     0.001145995
     0.001201994
     0.001040079
     0.001012389
     0.000876481
     0.001004057
     0.000925759
     0.000918481
     0.000809436
     0.000821415
     0.000789026
     0.000813591
     0.00068724
     0.000703664
     0.000756499
     0.000682395
     0.000586809
     0.000578912
     0.00049449
     0.000509462
     0.000464834
     0.00045288
     0.000404728
     0.000394017
     0.000356244
     0.000352201
     0.000281882
     0.000271873
     0.00022954
     0.000237268
     0.000188778
     0.000170614
     0.000129775
     9.31903E-05
     6.61896E-05
     2.2146E-05
     $ probabilities per bin
F14:p 8
F24:p 9
F34:p 10
F44:p 11
F54:p 12
F64:p 13
F74:p 14
F84:p 15
F94:p 16
F104:p 17
F114:p 18
F124:p 19
F134:p 20
F144:p 21
F154:p 22
F164:p 23
F174:p 24
F184:p 25
F194:p 26
F204:p 27
F214:p 28
E0 0.02 0.1    $ 2 energy bins
EM0 0 1     $ Removing particles with <20 keV
M1 73000 4 6000 3     $ Ta4C3 MXene film
M2 6000 22 1000 10 7000 2 8000 5     $ C22H10N2O5 Kapton tape
M3 6012 -0.000124 7014 -0.755267 8016 -0.231781
            18040 -0.012827     $ Dry air (sea level)
M4 6000 76 1000 114 8000 49     $ Scotch tape (cellulose acetate)

 

[Alex A]

Please upload as an attachment with .txt added in future. Or you can use bbcode CODE tags which may keep most of the formatting for short pastes. I didn't see any obvious errors on reading so I fixed the formatting and ran mcnp with ip to plot the geometry.

mcnp ip inp=scotch
(let it do a default plot)
(clicked the plot> button)
px 33.101
extent 1.1,1.1

Which shows the Kapton tape, I think. The dotted lines suggest a geometry error in the corners. If this is four sections of tape those corner bits would be doubled up.

 

[MadGander]

Please upload as an attachment with .txt added in future. Or you can use bbcode CODE tags which may keep most of the formatting for short pastes. I didn't see any obvious errors on reading so I fixed the formatting and ran mcnp with ip to plot the geometry.

mcnp ip inp=scotch
(let it do a default plot)
(clicked the plot> button)
px 33.101
extent 1.1,1.1

Which shows the Kapton tape, I think. The dotted lines suggest a geometry error in the corners. If this is four sections of tape those corner bits would be doubled up.

Recoded the Kapton so that there wasn't any overlap and I'm still getting an issue. I think it has to do with cell 29 (my bounding sphere). Here's the output file. As you can see, none of the tally cells are recording any particles (in either energy bin).