last modified: 20-FEB-2008 | catalog | categories | new | search |

DLC-0224 ZZ-ALBEDO-DATA.

ZZ ALBEDO-DATA, Data for the Calculation of Albedos from Concrete, Iron, Lead and Water for Photons and Neutrons

top ]
1. NAME OR DESIGNATION:  ZZ-ALBEDO-DATA.
top ]
2. COMPUTERS
To submit a request, click below on the link of the version you wish to order. Only liaison officers are authorised to submit online requests. Rules for requesters are available here.
Program name Package id Status Status date
ZZ-ALBEDO-DATA DLC-0224/01 Arrived 20-FEB-2008

Machines used:

Package ID Orig. computer Test computer
DLC-0224/01 Many Computers
top ]
3. DESCRIPTION

The use of albedo techniques is central to many radiation streaming codes and has been widely used as an alternative to much more expensive transport calculations. Key to the albedo technique is the availability of either a large set of albedo data or, preferably, an empirical formula that approximates the albedo over the range of source energies and incident and exit radiation directions involved in a particular problem. Previously proposed neutron and photon albedo approximating formulas have been based on limited energy-angular ranges, a single reflecting material, old cross section data, and, most important, obsolete fluence-to-dose response functions. This library contains differential neutron dose albedo functions, based on modern cross section and response function data.
  
Newly evaluated parameters are tabulated for several empirical differential dose albedo formulas. The albedos considered are (1) two approximations for photon albedo, (2) a new approximation for the neutron albedo, and (3) the secondary-photon albedo for incident neutrons. Albedo data is provided for four materials: concrete, iron, lead, and water. Unlike previous compilations of albedo data, modern dosimetric units have been employed. Data are presented for (1) the ambient dose equivalent H*(10mm) and (2) the effective dose equivalent for anteroposterior (AP) illumination of the ICRP anthropomorphic phantom.
top ]
4. METHODS

Monte Carlo code, MCNP, was used to calculate the albedo reflected from thick slabs of various materials. In particular, a homogeneous cylindrical slab surrounded by a vacuum was used. The incident neutrons were modeled by a point monodirectional source positioned just inside the center of the circular scoring (reflecting) surface. This was done to facilitate scoring because all particles crossing the surface must be outgoing (reflected) particles. Slab thickness and radius were sufficiently large (1000 cm) so that negligible numbers of neutrons were transmitted through the slab or radial surface. Energy of the source neutrons was sampled uniformly over an energy group or from a fission neutron distribution.
  
The MCNP calculated differential dose albedos were used to obtain extensive sets of values for a  wide range of incident energies, incident directions, and reflected directions. To make easy use of these results, empirical approximating functions were sought that could accurately reproduce the calculated albedos. The parameters in these empirical albedos functions were estimated by fitting the approximating functions to MCNP calculated values. A global fit was used that minimized the maximum absolute error between the function and the calculated data.
top ]
5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM
top ]
6. TYPICAL RUNNING TIME:  The ALBEDOS interactive program runs in seconds.
top ]
7. UNUSUAL FEATURES
top ]
8. RELATED OR AUXILIARY PROGRAMS

ALBEDOS: A program to evaluate the 24-parameter differential neutron dose albedos using a new albedo approximation.
The source code and a Windows executable created with Lahey Fortran 90 are in this distribution. The program reads ASCII data files for the parameter of the albedo approximation. The data files are ASCII files of the tables in the reference.
top ]
9. STATUS
Package ID Status date Status
DLC-0224/01 20-FEB-2008 Masterfiled Arrived
top ]
10. REFERENCES
DLC-0224/01, included references:
- R. C. Brockhoff and J. K. Shultis:
Data for the Calculation of Albedos from Concrete, Iron, Lead and Water for
Photons and Neutrons, Kansas State University, Engineering Experiment Station,
Report 301 (Sept. 2005, revised March 2006)
top ]
11. HARDWARE REQUIREMENTS
top ]
12. PROGRAMMING LANGUAGE(S) USED

No item found

top ]
13. SOFTWARE REQUIREMENTS
top ]
14. OTHER PROGRAMMING OR OPERATING INFORMATION

The various tables of fit coefficients for approximating albedo formulas are collected as ASCII machine readable files.
The data in the report have been extracted from the appendices of the dissertation Calculation of the Albedos for Neutrons and Photons by R.C. Brockhoff, KSU (2003). The name of each file refers to the Table number in the report.
top ]
15. NAME AND ESTABLISHMENT OF AUTHORS: Kansas State University, Manhattan, Kansas, USA.
top ]
16. MATERIAL AVAILABLE
DLC-0224/01
ASCII data files
ALBEDOS code
Electronic document
top ]
17. CATEGORIES
  • Z. Data.

Keywords: albedo, concretes, iron, lead, neutron, photon, water.