1. NAME OR DESIGNATION OF PROGRAM - 
    ECBO                                                                        

 2. COMPUTER FOR WHICH PROGRAM IS DESIGNED AND OTHER MACHINE VERSION            
    PACKAGES AVAILABLE - 
    Program-name         Package-ID     Orig. Computer   Test Computer          
    ------------         ----------     --------------   -------------          
    ECBO                                Linux PC                                

 3. DESCRIPTION OF PROGRAM OR FUNCTION - 
    ECBO is a system to perform an efficient Monte Carlo radiation shielding    
    analysis with MCNP code: using variance reduction parameters automatically  
    prepared with adjoint flux distributions in R-Z two-dimensional system.     
    The adjoint flux distributions are obtained with two-dimensional Sn         
    transport code DORT.
    ECBO performs both source and transport biasing for fixed source problems.
    ECBO is developed for shielding analysis of transport casks, but is         
    applicable for any shielding analysis problem modeled in R-Z two-           
    dimensional system: for example, skyshine radiation problem in which        
    scattering space is presented with cylindrical geometry.

 4. METHOD OF SOLUTION - 
    An ECBO simulation is made in 3 steps: 
    It calculates adjoint flux distributions using two-dimensional Sn transport 
    code DORT, 
    It determines variance reduction parameters based on the adjoint flux       
    distributions, and 
    It simulates Monte Carlo radiation shielding analyses with MCNP code,       
    MCNP4B, MCNP4C2 or MCNP5, and adequately reduced variances will be          
    calculated at specified measuring or detecting points.

 5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM - 
    Two-dimensional ECBO is limited in application to R-Z cylindrical geometry  
    systems.

 6. TYPICAL RUNNING TIME - 

 7. UNUSUAL FEATURES OF THE PROGRAM - 

 8. RELATED AND AUXILIARY PROGRAMS - 

 9. STATUS - 

10. REFERENCES -                                                                
    - Susumu MITAKE and Osamu SATO:                                             
      ECBO: Monte Carlo Radiation Shielding Analysis Systems with Variance      
      Reduction Technique Based on the Sn Adjoint Calculations - User's Manual -
      INS/S99-03(M)(Rev) (March 2000, and December 2004 (Rev))
    - S. Mitake, O. Sato and H. Tsunoda:                                        
      Application of Biasing Optimization Techniques to Monte Carlo Shielding   
      Analysis of Transport Cask                                                
      Proc. of Monte Carlo 2000 Conf. (Lisbon, 23-26 October 2000)

11. MACHINE REQUIREMENTS - 
    Pentium 4 CPU                                                               

12. PROGRAMMING LANGUAGE USED. - 
    FORTRAN                                                                     

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED - 
    RedHat Linux 8.0 Professional                                               

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS - 

15. NAME AND ESTABLISHMENT OF AUTHORS - 
    Institute of Nuclear Safety, NUPEC                                          
      Tokyo, Japan                                                              
    Mitsubishi Research Institute, Inc.                                         
      Tokyo, Japan                                                              

16. CONTENTS OF CODE PACKAGE - 
    DOS compressed zip files containing program sources, sample case input and  
    output, and shell scripts for executing the ECBO systems.  Reference        
    documents in PDF.

17. CATEGORY. G J 
    KEYWORDS - 
    radiation shielding, neutron, gamma-ray, Monte Carlo method,                
    variance reduction technique, source biasing, transport biasing,            
    two-dimensions, cylindrical geometry