Geant4 can do the job: http://geant4.cern.ch/

It is for free.

MNCP will also work: https://laws.lanl.gov/vhosts/mcnp.lanl.gov/index.shtml

But here you have to apply to be accpeted as a user.

Does your simulation start with the neutron beam or do you also need to model the neutron production process?

Apply for MCNP. It's free at the moment. It just takes a bit of effort to fill out the forms.

For sure the best is MCNP

It is better use mcnp(2.6.0) with complete library of neutron cross section

Also, GEANT requires some programming ability, whereas MCNP is just reading the manual. There are also some good primers available on the web. RSICC in North America distributes MCNP5/MCNPX and in Europe it's the OECD/NEA. Good luck.

The MCNP code is the better for simulations with neutrons. The price of the new version is about $ 1,000.00.

MCNP is quiet easy to use. A simple input file could be the interface between user and the code. I think its now free from RSICC.

Thanks a lot for Valuable response

Dear Mr. Günter Weber , also need to model the neutron production process? Any help in this regard

I am also a mcnp user and have a license. The principal difficulty at the moment, at least for us, brazilian citizens on the "devils side", is to purchase the software. I submited the form three or four months ago and the DOE is still analyzing my past, my present, my future and nobody is able to tell me if I can run a simple monte carlo calculation or not.

With MCNP, a Monte Carlo code, you will be able to simulate ALL situations and perform aal calculations. This will allow you to analyse also the parameters. You are free to choose the accuracy of your calculations. There is no limitations in the use of MCNP codes.

MCNP requires a training to be able to use it correctly. But when this step is done you have a very useful tool.

Another advantage of the MCNP is the existance of the forum where you can post all your questions. And someone in the wolrd who saved the problem will help you immediately.

The best is GEANT4 and its free

As you can see in the answers, MCNP and GEANT are adviced.

With MCNP, you will be able to simulate everything.

Some versions are free, you have the forum and you can ask for a training at thre levels: basic, intermediate and expert.

Actually you can use both GEANT4 and MCNP. GEANT4 is open source so need some programming skills but MCNP has some built-in libraries. If you want to be initiative and do interdisciplinary research you'd better work with open source.

Obtaining MCNP/MCNPX can be difficult/slow for non-US citizens because of export controls. If you are concerned about that, you can ask for just the executable files and not the source code. That will help speed up the request. GEANT does not have similar restrictions. Both programs have their advantages and disadvantages. Most people prefer the one they are familiar with, to avoid a second learning curve.

I think FLUKA is also a choice. Geant4 needs some C++ programing skills, and it is a little omplex to use. FLUkA uses just like MCNP and it is free.

As stated above, you have MCNP5(6)/MCNPX, free but requires approvals. GEANT is free, but requires programming knowledge. There is also EGS from NRC here in Canada. It's also free but requires knowledge of MORTRAN a modified version of FORTRAN. Check out RSICCS or NEA for other programs available.

http://rsicc.ornl.gov/Default.aspx

(North America)

http://www.oecd-nea.org/dbprog/mcnp-lib.html

(Europe)

My personal choice is MCNP/MCNPX (I mostly use MCNPX). I believe it is the easiest to use, and the best supported. There are numerous forums and some great primers on the web to get you started. I also seen a lot of shielding samples on the NET. Check out:

http://mcnpx.net/

http://web.utk.edu/~rpevey/public/NE406/MCNP%20primer.pdf

Good luck and have fun.

As explained before, there are several codes available. MCNPX is a good reference, FLUKA, PHITS, SHIELD-HIT and GEANT4 work too (maybe other codes). If you select GEANT4, I suggest you make a try to GATE, which is a GEANT4-based application that DOES NOT NEDD PROGRAMMING! Only command lines. The community is growing and it might be an interesting possibility: http://www.opengatecollaboration.org/. Just register and try the examples. I suggest you download the virtual box to make the first try, which is a ready to use Linux environment with GATE set-up ready on it! Have fun!

Unfortunately, EGS (mentioned above) doesn't do neutron calculations. It's aimed much more at charged particles, and for that, it's very good, with a well developed interface and a big user base. But it won't help with your neutron shielding calculations.

Fluka: http://www.fluka.org is one of the code you can use and its free.

Dear Aung Than Doing,

I think that the software most suitable for a shielding calculation of spectrum of neutrons is MCNP, but I don't know what its price. You can get information in https://mcnp.lanl.gov/

Best regards,

Adriano M. Santos

MCNP is certainly one option, however it has export controls from the U.S. government because it is also useful for reactors/weapons development.  Fluka and Geant are not under U.S. government control and can do the same thing.  They all have the learning curves.  Most people stick with whatever they learned first because they all do a good job so their is no incentive to learn something new once you have something that works.  GATE and TOPAS are essentially wrappers for GEANT4 to make it more user friendly, so they could be explored as well.

Dear Charles Bloch,

You have correctly addressed issue of MCNP. But as I am working on EGSnrc, BEAMnrc and FLUKA as per my opinion, FLUKA works good for most of the simulations of ion therapy, neutrons including photon and electrons so if any one does not have MCNP it should not be a matter of concern. 

 I concur with Amol

Dear Amol S Jagtap

GEANT 4  is Recent advances  for radiation shielding  calculation method 

It is freely available.  

MCNP and ANISN can be used for shielding calculation. The cost is about US$650/ for each code.

In this case, Gent4 and MCNP would be useful for mentioned investigations. Geant4 is an open source code that you can obtain from their web site. In contrast, MCNP need registration from RSICC.

You can use Gate or Fluka for shielding calculations.

Price: free.

mcnp

If you are proficient in c++ you can use geant4. If not you can use fluka, gamos or gate. Price for any is $0.

thanks

Dear Afshan Ashfaq

open access to the the following software can help you much

Gate or Fluka, GEANT4 for calculations.