Benzine

 BENZINE   GA         EVAL-DEC69 KOPPEL,HOUSTON,BORGONOVI         
 REF.1 (1978)         DIST-MAY10                       20100309   
----JENDL-4.0         MATERIAL   40                               
-----THERMAL NEUTRON SCATTERING DATA                              
------ENDF-6 FORMAT                                               
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 The data were taken from ENDF/B-VI.8.                            
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 TEMPERATURES = 296 350 400 450 500 600 800 1000 DEG K.           
                                                                  
 HISTORY                                                          
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 THIS EVALUATION WAS PRODUCED AT GENERAL ATOMIC IN 1969 USING     
 THE GA CODE GASKET (SEE REF.1).  IT WAS CONVERTED TO             
 ENDF-6 FORMAT AT LOS ALAMOS IN 1989.  THE ONLY CHANGES           
 MADE TO THE CONTENTS WERE ADJUSTMENTS OF CROSS SECTIONS          
 TO MATCH THE ENDF/B-VI VALUES.                                   
                                                                  
 THEORY                                                           
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 THE BENZINE MOLECULE HAS AN HEXAGONAL PLANAR STRUCTURE WITH      
 SYMMETRY D6H, CARBON-CARBON BOND LENGTH OF 1.39 ANG, AND         
 CARBON-HYDROGEN BOND LENGTH OF 1.08 ANG.  IN CONSTRUCTING A      
 MODEL FOR THE ATOMIC VIBRATIONS, IT WAS ASSUMED (REF.2) THAT     
 THERE IS NO INTERACTION BETWEEN VIBRATIONAL AND ROTATIONAL       
 STATES OF THE MOLECULE, AND THAT THE HINDERED ROTATIONS THAT     
 DESCRIBE THE INTERACTIONS OF MOLECULES IN THE LIQUID CAN BE      
 REPRESENTED BY TRANSLATIONS OF THE WHOLE MOLECULE WITH AN        
 EFFECTIVE MASS.  CONTINUOUS FREQUENCY DISCTRIBUTIONS WERE THEN   
 OBTAINED FOR THE HYDROGEN AND CARBON ATOMS USING METHODS         
 DESCRIBED IN (REF. 3).  THE CLUSTER OF FREQUENCES CLOSELY        
 SPACED AROUND 0.38 EV WAS LUMPED INTO A SINGLE OSCILLATOR.       
 THE GASKET CODE WAS THEN USED TO COMPUTE SEPARATE S(ALPHA,BETA)  
 FUNCTIONS FOR HYDROGEN AND CARBON.  THE SCATTERING LAWS WERE     
 COMBINED AND ADJUSTED TO BE USED WITH THE HYDROGEN FREE-ATOM CROS
 SECTION.  THE CARBON FREE-ATOM CROSS SECTION HAS BEEN PROVIDED   
 FOR USE WITH THE SHORT-COLLISION-TIME APPROXIMATION (SCT).       
 THUS, THE THERMAL CROSS SECTION COMPUTED FROM EITHER S(ALPHA,    
 BETA) OR BY THE SCT APPROXIMATION GIVES AN ASYMPTOTIC LIMIT OF   
 APPROXIMATELY 6*20+6*4.7 BARNS.                                  
                                                                  
 REFERENCES                                                       
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 1. J.U.KOPPEL AND D.H.HOUSTON, REFERENCE MANUAL FOR ENDF THERMAL 
    NEUTRON SCATTERING DATA, GENERAL ATOMIC REPORT GA-8774        
    REVISED AND REISSUED AS ENDF-269 BY THE NATIONAL NUCLEAR      
    DATA CENTER, JULY 1978.                                       
 2. D.SPREVAK, G.M.BORGONOVI, J.M.NEILL, AND G.W.CARRIVEAU,       
    NUKLEONIK 11, 233(1968).                                      
 3. D.SPREVAK, G.M.BORGONOVI, G.W.CARRIVEAU, AND J.M.NEILL,       
    "NEUTRON THERMALIZATION IN BENZINE," GENERAL DYNAMICS         
    REPORT GA-8185 (AUGUST 1967).