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NEA-1688 SACALC2B/SACALC_CYL. (Abstract last modified 21-FEB-2007)


SACALC_CYL, Calculates the average solid angle subtended by a volume
SACALC2B, Calculates the average solid angle for source-detector geometries

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Abstract Table of Contents:

NAME | COMPUTER | PROBLEM | SOLUTION | RESTRICTIONS | CPU | FEATURES | AUXILIARIES | STATUS | REFERENCES | REQUIREMENTS | LANGUAGE | OPERATING SYSTEM | OTHER RESTRICTIONS | AUTHOR | MATERIAL | CATEGORIES |

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1. NAME OR DESIGNATION OF PROGRAM - SACALC2B and SACALC_CYL.


2. COMPUTER FOR WHICH PROGRAM IS DESIGNED AND OTHER MACHINE VERSION PACKAGES AVAILABLE -

To request or retrieve programs click on the one of the active versions below. A password and special authorization is required.

Explanation of the status codes.

Program-name         Package-ID  Status
SACALC               NEA-1688/01 Obsolete
SACALC2              NEA-1688/02 Obsolete
SACALC2B             NEA-1688/03 Tested
SACALC_CYL           NEA-1688/04 Tested

Machines used:
Package-ID     Orig.Computer                       Test Computer
NEA-1688/03    IBM PC,PC Windows                   PC Windows
NEA-1688/04    IBM PC,PC Windows                   PC Windows

3. DESCRIPTION OF PROGRAM OR FUNCTION - 
SACALC2B calculates the average solid angle subtended by a rectangular or circular detector window to a coaxial or non-coaxial rectangular, circular or point source, including where the source and detector planes are not parallel.
  
SACALC_CYL calculates the average solid angle subtended by a cylinder to a rectangular or circular source, plane or thick, at any location and orientation. This is needed, for example, in calculating the intrinsic gamma efficiency of a detector such as a GM tube. The program also calculates the number of hits on the cylinder side and on each end, and the average path length through the detector volume (assuming no scattering or absorption). Point sources can be modelled by using a circular source of zero radius.

NEA-1688/03:

Documentation has been updated (January 2006).


4. METHODS - 
The program uses a Monte Carlo method to calculate average solid angle for source-detector geometries that are difficult to analyse by analytical methods. The values of solid angle are calculated to accuracies of typically better than 0.1%. The calculated values from the Monte Carlo method agree closely with those produced by polygon approximation and numerical integration by Gardner and Verghese, and others.


5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM -
The program models a circular or rectangular detector in planes that are not necessarily coaxial, nor parallel. Point sources can be modelled by using a circular source of zero radius. The sources are assumed to be uniformly distributed.

NEA-1688/04:

In SACALC_CYL, to avoid rounding errors, differences less than 1e-12 are assumed to be zero.


6. TYPICAL RUNNING TIME - It depends on the number of random events selected by the user.


7. UNUSUAL FEATURES - The program models non-coaxial and non-parallel geometries, and combinations of source and detector shapes.


8. RELATED OR AUXILIARY PROGRAMS -


9. STATUS
NEA-1688/01: 01-OCT-2003 Obsolete
NEA-1688/02: 19-JUN-2006 Obsolete
NEA-1688/03: 19-JUN-2006 Tested at NEADB
NEA-1688/04: 21-FEB-2007 Tested at NEADB


10. REFERENCES  - 
- R. Whitcher:
Calculation of the average solid angle subtended by a detector to source in a parallel plane by a Monte Carlo method (Rad. Prot. Dosimetry 102 (4) pp365-369. 2002)
- The use of a Monte Carlo method to calculate the average solid angle subtended by a detector to source in a non-parallel plane (Radiation Protection Dosimetry 2003 104(2):167-171)
- R. Whitcher:
A Monte Carlo Method to Calculate the Average Solid Angle Subtended by a Right Cylinder to a Source that is Circular or Rectangular, Plane or Thick, at any Position and Orientation (Radiation Protection Dosimetry 2006 118(4):459-474)
NEA-1688/03:
- R. Whitcher:
SACALC2B How to Use (January 2006)
NEA-1688/04:
- R. Whitcher:
SACALC_CYL How to Use (October 2006)


11. HARDWARE REQUIREMENTS - The program runs on any Pentium (or compatible) processor PC, operating Microsoft Windows OS 95 or later. A screen resolution of 800x600 or higher is preferable, but not essential.


12. PROGRAMMING LANGUAGE -NEA-1688/03: DELPHI V4 
NEA-1688/04: DELPHI V4 


13. SOFTWARE REQUIREMENTS - Microsoft Windows 95, 98, ME, 2000, XP, NT.


14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS -


15. NAME AND ESTABLISHMENT OF AUTHORS -
Ralph WHITCHER
West Sussex County Council
65A Westgate, The Tannery,
Chichester, PO19 3RJ
United Kingdom


16. MATERIAL AVAILABLE -NEA-1688/03:
SACALC2.EXE Executable to run the SACALC2 code
SACALC2 Documentation both in Word and PDF Formats
Readme.txt Readme file
7 source files
NEA-1688/04:
SACALC_CYL.doc  manual
sacalc_cyl.exe  executable file


17. CATEGORIES  - 

- J.  Gamma Heating and Shield Design
- O.  Experimental Data Processing


Keywords: DETECTORS, MONTE CARLO METHOD, SOURCE

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