Re: Low-mat option

From: Alberto Fasso' <>
Date: Wed, 31 Jul 2013 02:36:40 -0700 (PDT)

Dear Chen yuan,

it looks to me that you have perfectly understood the the low-mat option.
In your input file, you have two materials: CARBON and GRAPHITE.
CARBON is a Fluka material (pre-defined) and also a low-energy neutron material
(as you can see in Chapter 10 of the Manual). On the other hand, GRAPHITE
is also a Fluka material (defined by you with a MATERIAL card), but it is not a
low-energy neutron material (there is no material called GRAPHITE in the list
of Chapter 10). Therefore, you must tell the program to use for GRAPHITE the
CARBON low-energy neutron material. And you did it correctly with the LOW-MAT

I take this opportunity to suggest to you two things. In command MATERIAL:
1) leave WHAT(2) blank, or equal to 0.0. This is because FLUKA has its own
     table of atomic weights and you better not change them
2) leave WHAT(4) blank, or equal to 0.0. Since you are using a name-based
     input, FLUKA takes care of assigning the proper number to materials.
     Your input is correct, but leaving the material number blank you can avoid
     possible problems.

Best regards,


On Tue, 30 Jul 2013, wrote:

> Good morning,
> I am a beginner user of fluka. I can't fully understand low-mat option.
> In the low-mat option, How to distinguish Fluka material and
> corresponding low-energy neutron material? Could you give me a detailed
> explain? Or could you give me a simple example to help me understand low-mat
> option? The attachment is my input file.Is there any problem?
> Best wishes,
> Yours,
> Chen yuan
Received on Wed Jul 31 2013 - 15:25:48 CEST

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