Is there a function in openmc that is similar to the FM card（multiplication） in mcnp？

User Support
1

Hi, I’m a new openmc scholar。
Is there a function in openmc that is similar to the FM card（multiplication） in mcnp？
Such as：

f34:n    5001                                                                      
e34      1e-2 10                                                              
fm34     2.51461           $kerma factor unit:(Gy.cm2)
de34      1.0E-9
          1.0E-8
          2.5E-8
          1.0E-7
          2.0E-7
          5.0E-7
2

Yes, the EnergyFunctionFilter class serves the same purpose as the FM card in MCNP.

3

Thanks very much! @paulromano
From the description of the EnergyFunctionFilter function, there is no parameter that can be used as a multiplication factor (FM).

f34:n    5001                                                                      
e34      1e-2 10                                                              
fm34     2.51461           $kerma factor unit:(Gy.cm2)
de34      1.0E-9
          1.0E-8
          2.5E-8
          1.0E-7
          2.0E-7
          5.0E-7
          1.0E-6
          2.0E-6
          5.0E-6
          1.0E-5
          2.0E-5
          5.0E-5
          1.0E-4
          2.0E-4
          5.0E-4
          0.001 
          0.002 
          0.005 
          0.01  
          0.02  
          0.03  
          0.05  
          0.07  
          0.1   
          0.15  
          0.2   
          0.3   
          0.5   
          0.7   
          0.9   
          1.0   
          1.2   
          1.5   
          2.0   
          3.0   
          4.0   
          5.0   
          6.0   
          7.0   
          8.0   
          9.0   
          10.0  
          12.0  
          14.0  
          15.0  
          16.0  
          18.0  
          20.0  
          21.0  
          30.0  
          50.0  
          75.0  
          100   
          130   
          150   
          180   
          200   
          300   
          400   
          500   
          600   
          700   
          800   
          900   
          1000  
          2000  
          5000  
          10000      
df34         3.09
             3.55
             4.00
             5.20
             5.87
             6.59
             7.03
             7.39
             7.71
             7.82
             7.84
             7.82
             7.79
             7.73
             7.54
             7.54
             7.61
             7.97
             9.11
            12.2
            15.7
            23.0
            30.6
            41.9
            60.6
            78.8
           114
           177
           232
           279
           301
           330
           365
           407
           458
           483
           494
           498
           499
           499
           500
           500
           499
           495
           493
           490
           484
           477
           474
           453
           433
           420
           402
           382
           373
           363
           359
           363
           389
           422
           457
           486
           508
           524
           537
           612
           716
           933

Using the MCNP input card as an example, how should I write it using OpenMC?

4

If you just want a single multiplicative constant, you could do:

multiplier = openmc.EnergyFunctionFilter([0.0, 1.0e10], [2.51461, 2.51461])

That is, it interpolates between 0 and 10 GeV with the same value at each point, so no matter what the incident energy of the particle, the function will always evaluate to 2.51461.