CCC-0119 ELBA.

1. NAME OR DESIGNATION OF PROGRAM:  ELBA.
Electron and Bremsstrahlung Dose Rate Code.

3. DESCRIPTION OF PROBLEM OR FUNCTION

ELBA takes an incident isotropic electron flux with a given differential energy spectrum and calculates the dose rate received from bremsstrahlung produced in a plane aluminium shield placed in front of the receiver. There is an option to also calculate the electron dose rate from the same  source.

4. METHOD OF SOLUTION

The electron differential spectrum as a function of depth is inferred by assuming that electrons travel straight ahead and that distance travelled and energy are related by a range-energy relationship. The electron dose rate at a given depth is calculated by integrating, over energy and direction, the product of the electron flux, the stopping power, and the appropriate flux-  to-dose rate conversion factor.
The bremsstrahlung source is assumed to be plane and isotropic at a  given depth. This source is defined as the integral over energy and  direction of the product of photon energy, the differential bremsstrahlung spectrum from electrons of a given energy, and the electron flux differential spectrum. The differential bremsstrahlung spectrum is derived from the Born approximation cross section multiplied by a correction factor. The bremsstrahlung dose rate is obtained by integrating, over photon energy and slab volume, the product of the bremsstrahlung source, photon energy flux-to-dose rate conversion factor, buildup factor, and attenuation kernel. The  buil-dup factor assumed is a plane isotropic buildup factor generate by Monte Carlo calculations. The integrations are performed by evaluating the integrand at the midpoint of each integration step, multiplying by the step width, and summing the result.
The incident electron spectrum, dose rate conversion factors, and range formula coefficients are input by the user. The buildup factor information is contained in three DATA statements in subroutine BURP.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

There are limitations on the dimensions of certain arrays, but these dimensions probably can be increased to meet the user's requirements.

6. TYPICAL RUNNING TIME

Estimated running time of the packaged sample problem on the IBM 7090: 13.8 minutes.

7. UNUSUAL FEATURES OF THE PROGRAM

The code was written for the IBM 7094 using standard I-O units.

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES

- Martin O. Burrell, J.J. Wright, and John W. Watta, JR.,
  "The Calculation of Electron and Bremsstrahlung Dose Rates",
  NASA-SP-169(ANS-SD-5) pp. 529-538 (1968).
- Informal notes.

11. MACHINE REQUIREMENTS:

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHOR

Contributed by:
          Radiation Safety Information Computational Center
          Oak Ridge National Laboratory
          Oak Ridge, Tennessee, USA

Developed by: Space Sciences Laboratory
              NASA George C. Marshall Space Flight Center
              Huntsville, Alabama, USA

File name	File description	Records
CCC0119_01.001	SOURCE PROGRAM (F4,EBCDIC)	527
CCC0119_01.002	SAMPLE PROBLEM INPUT DATA (EBCDIC)	24
CCC0119_01.003	SAMPLE PROBLEM PRINTED OUTPUT	65