RSICC CODE PACKAGE CCC-738

 

1.  NAME AND TITLE

BULK_C-12:  Code System to Estimate Neutron and Photon Effective Dose Rates from Medium Energy Protons or Carbon Ions Through Concrete or Concrete/Iron.

 

2.  CONTRIBUTORS

AREVA NP GmbH Dep. NEPR-G, Erlangen, Germany, through OECD Nuclear Energy Agency Data Bank, Issy-les-Moulineaux, France.

 

3.  CODING LANGUAGE AND COMPUTER

Microsoft Excel Visual Basic; Pentium computers (C00738PC58600).

NEA Package ID:   NEA-1771/01.

 

4.  NATURE OF PROBLEM SOLVED

BULK_C-12 is a tool to estimate neutron and photon effective dose rates from medium energy protons or carbon ions penetrating through a concrete layer or two layers with iron and concrete in a particle accelerator facility (protons with energies from 50 to 500 MeV, 12C ions with energies from 155 to 430 MeV/u). This tool can also be used for shielding calculations considering various particle energies and - with limited accuracy - diverse beam directions as occurring in particle treatment facilities.

 

5.  METHOD OF SOLUTION

BULK_C-12 is based on BULK-I (NEA-127/01). As in its predecessor, a simple formula is adopted for not only the equilibrium region but also for the build-up region; and the parameters for concrete or two layers with (first) iron and (second) concrete are numerically obtained with the Monte Carlo code MCNPX. The geometry - which is simplified in comparison to BULK-I - used in the tool consists of a target (radiation source) placed at the origin in front of a wall. The target is assumed to be of thick iron (proton case) or carbon or copper (both for 12C case) as a typical component of the accelerator. Particles with various energies and directions are taken into account in the dose rate calculation based on the gantry employed in a particle beam treatment facility. The dose rates at estimator points are calculated considering the emission angle relative to the particle beam which can be either given by the user or calculated in a pop-up window of the tool. The distance from the target to the inner surface and the thickness of the wall are given by the user. Estimators are set in forward direction in the wall; the penetration into the wall is always assumed to be perpendicular for each emission angle. The attenuation in the air (0.001239 g/cm3) is considered. In case of protons, BULK_C-12 uses the parameters of BULK-I. In case of 12C ions, the data represented in the Hand-book on Secondary Particle Production and Transport by High-Energy Heavy Ions of Nakamura and Heilbronn (2006) were used for the elaboration of the necessary parameters.

 

6.  RESTRICTIONS OR LIMITATIONS

BULK_C-12 is not applicable for radiation streaming problems like a maze and a duct or a skyshine problem. In case of larger emission angles for secondary particles, the accuracy of the results is limited. The application limits of the tool are as follows:
1. Proton energy: 50 - 500 MeV
2. 12C ion energy: 155 - 430 MeV/u (2 bins: 180 and 400 MeV/u, limited accuracy of results in intermediate range) 
3. Emission angle relative to beam direction: 0 - 90 degrees

(6 bins, limited accuracy of results for > 45 degrees based on comparison with published FLUKA calculations
4. Barrier thickness in concrete: 0 - 400 cm (assumed density 2.1 g/cm3, ordinary concrete)
5. Barrier thickness in iron: 0, 25, 50 and 70 cm (assumed density 7.83 g/c3).

 

7.  TYPICAL RUNNING TIME

The program is interactive.

 

8.  COMPUTER HARDWARE REQUIREMENTS

The Windows application runs on personal computers

 

9.  COMPUTER SOFTWARE REQUIREMENTS

BULK_C-12 is a Microsoft Office EXCEL 2003 application that runs under Microsoft Windows XP. No compilers are required.

 

10. REFERENCES

10.a  included in documentation:

“Program BULK_C-12,” AREVA report (2006).

10.b  background reference:

Sabine Norosinski (Diplomarbeit an der Hochschule Zittau/Goerlitz), “Erstellung eines Handbuches zur Abschaetzung von Abschirmungen (Protonen und 12C-Ionen als Primaerteilchen)” (in German only) (2006-05-31)

T. Nakamura, L. Heilbronn, “Handbook on Secondary Particle Production and Transport by High-Energy Heavy Ions,” World Scientific Publishing Co. Pte. Ltd., Singapore (2006).

 

11. CONTENTS OF CODE PACKAGE

The package is transmitted on a CD which includes the referenced document in 10.a and a WinZIP file containing the Excel file.

 

12. DATE OF ABSTRACT

April 2008.

 

KEYWORDS:  HEAVY IONS; NEUTRON; PROTON