======================================================================= Virgin 

                                                                         Virgin 

      PROGRAM VIRGIN                                                     Virgin 

      VERSION 76-1 (NOVEMBER 1976)                                       Virgin 

      VERSION 84-1 (JUNE 1984)   *DOUBLE PRECISION ENERGY                Virgin 

      VERSION 86-1 (JANUARY 1986)*FORTRAN-77/H VERSION                   Virgin 

      VERSION 88-1 (JULY 1988)   *OPTION...INTERNALLY DEFINE ALL I/O     Virgin 

                                  FILE NAMES (SEE, SUBROUTINE FILEIO     Virgin 

                                  FOR DETAILS).                          Virgin 

                                 *IMPROVED BASED ON USER COMMENTS.       Virgin 

      VERSION 89-1 (JANUARY 1989)*PSYCHOANALYZED BY PROGRAM FREUD TO     Virgin 

                                  INSURE PROGRAM WILL NOT DO ANYTHING    Virgin 

                                  CRAZY.                                 Virgin 

                                 *UPDATED TO USE NEW PROGRAM CONVERT     Virgin 

                                  KEYWORDS.                              Virgin 

                                 *ADDED LIVERMORE CIVIC COMPILER         Virgin 

                                  CONVENTIONS.                           Virgin 

      VERSION 92-1 (JANUARY 1992)*COMPLETE RE-WRITE                      Virgin 

                                 *OUTPUT IN PLOTTAB FORMAT               Virgin 

                                 *UP TO 2000 THICKNESSES                 Virgin 

                                 *INCREASED INCORE PAGE SIZE TO 6000     Virgin 

                                  CROSS SECTION POINTS                   Virgin 

                                 *ADDED PHOTON CALCULATIONS              Virgin 

                                 *ADDED BLACKBODY SPECTRUM               Virgin 

                                 *ADDED MULTIPLE LAYERS                  Virgin  

                                 *ADDED SPATIALLY DEPENDENT DENSITY      Virgin 

                                 *ADDED FORTRAN SAVE OPTION              Virgin 

                                 *COMPLETELY CONSISTENT I/O ROUTINES -   Virgin 

                                  TO MINIMIZE COMPUTER DEPENDENCE.       Virgin 

      VERSION 92-2 (MAY 1992)    *CORRECTED TO HANDLE MULTIGROUP CROSS   Virgin 

                                  SECTIONS AS INPUT IN ENDF/B FORMAT.    Virgin 

      VERSION 96-1 (JANUARY 1996) *COMPLETE RE-WRITE                     Virgin 

                                  *IMPROVED COMPUTER INDEPENDENCE        Virgin 

                                  *ALL DOUBLE PRECISION                  Virgin 

                                  *ON SCREEN OUTPUT                      Virgin 

                                  *UNIFORM TREATMENT OF ENDF/B I/O       Virgin 

                                  *IMPROVED OUTPUT PRECISION             Virgin 

                                  *DEFINED SCRATCH FILE NAMES            Virgin 

      VERSION 99-1 (MARCH 1999)   *CORRECTED CHARACTER TO FLOATING       Virgin 

                                   POINT READ FOR MORE DIGITS            Virgin 

                                  *UPDATED TEST FOR ENDF/B FORMAT        Virgin 

                                   VERSION BASED ON RECENT FORMAT CHANGE Virgin 

                                  *GENERAL IMPROVEMENTS BASED ON         Virgin 

                                   USER FEEDBACK                         Virgin 

      VERS. 2000-1 (FEBRUARY 2000)*GENERAL IMPROVEMENTS BASED ON         Virgin 

                                   USER FEEDBACK                         Virgin 

      VERS. 2002-1 (MAY 2002)     *OPTIONAL INPUT PARAMETERS             Virgin 

      VERS. 2004-1 (MARCH 2004)   *ADDED INCLUDE FOR COMMON              Virgin 

                                  *UP TO 2000 THICKNESSES                Virgin 

                                  *INCREASED INCORE PAGE SIZE TO 12,000  Virgin 

                                                                         Virgin 

      OWNED, MAINTAINED AND DISTRIBUTED BY                               Virgin 

      ------------------------------------                               Virgin 

      THE NUCLEAR DATA SECTION                                           Virgin 

      INTERNATIONAL ATOMIC ENERGY AGENCY                                 Virgin 

      P.O. BOX 100                                                       Virgin 

      A-1400, VIENNA, AUSTRIA                                            Virgin 

      EUROPE                                                             Virgin 

                                                                         Virgin 

      ORIGINALLY WRITTEN BY                                              Virgin 

      ------------------------------------                               Virgin 

      DERMOTT E. CULLEN                                                  Virgin 

      UNIVERSITY OF CALIFORNIA                                           Virgin 

      LAWRENCE LIVERMORE NATIONAL LABORATORY                             Virgin 

      L-159                                                              Virgin 

      P.O. BOX 808                                                       Virgin 

      LIVERMORE, CA 94550                                                Virgin 

      U.S.A.                                                             Virgin 

      TELEPHONE  925-423-7359                                            Virgin 

      E. MAIL    CULLEN1@LLNL.GOV                                        Virgin 

      WEBSITE    HTTP://WWW.LLNL.GOV/CULLEN1                             Virgin 

                                                                         Virgin 

      PURPOSE                                                            Virgin 

      -------                                                            Virgin 

      THIS PROGRAM IS DESIGNED TO CALCULATE UNCOLLIDED (I.E. VIRGIN)     Virgin 

      FLUX AND REACTIONS DUE TO TRANSMISSION OF A MONODIRECTIONAL        Virgin 

      BEAM OF NEUTRONS THROUGH ANY THICKNESS OF MATERIAL. IN ORDER       Virgin 

      TO SIMULATE AN EXPERIMENTAL MEASUREMENT THE RESULTS ARE GIVEN      Virgin 

      AS INTEGRALS OVER ENERGY TALLY GROUPS (AS OPPOSED TO POINTWISE     Virgin 

      IN ENERGY). BY TAKING THE RATIO OF REACTIONS TO FLUX IN EACH       Virgin 

      GROUP AN EQUIVALENT SPATIALLY DEPENDENT GROUP AVERAGED CROSS       Virgin 

      SECTION IS CALCULATED BY THE PROGRAM.                              Virgin 

                                                                         Virgin 

      EVALUATED DATA                                                     Virgin 

      --------------                                                     Virgin 

      THE EVALUATED DATA MUST BE IN THE ENDF/B FORMAT. HOWEVER IT        Virgin 

      MUST BE LINEAR-LINEAR INTERPOLABLE IN ENERGY-CROSS SECTION         Virgin 

      BETWEEN TABULATED POINTS. SINCE ONLY CROSS SECTIONS (FILE 3 OR 23) Virgin 

      ARE USED, THIS PROGRAM WILL WORK ON ANY VERSION OF ENDF/B          Virgin 

      (I.E. ENDF/B-I, II, III, IV, V OR VI).                             Virgin 

                                                                         Virgin 

      RELATED COMPUTER CODES                                             Virgin 

      ----------------------                                             Virgin 

      IN ORDER TO CONVERT ENDF/B DATA TO THE FORM REQUIRED BY THIS CODE  Virgin 

      THE FOLLOWING COMPUTER CODES MAY BE USED,                          Virgin 

                                                                         Virgin 

      LINEAR  - CONVERT FROM GENERAL ENDF/B INTERPOLATION TO LINEAR-     Virgin 

                LINEAR INTERPOLATION.                                    Virgin 

      RECENT  - ADD THE RESONANCE CONTRIBUTION TO TABULATED BACKGROUND   Virgin 

                CROSS SECTIONS TO OBTAIN LINEAR-LINEAR INTERPOLABLE      Virgin 

                RESULTS.                                                 Virgin 

      SIGMA1  - DOPPLER BROADEN CROSS SECTION TO OBTAIN LINEAR-LINEAR    Virgin 

                INTERPOLABLE RESULTS.                                    Virgin 

      MIXER   - MIX INDIVIDUAL MATERIALS TOGETHER TO DEFINE COMPOSITE    Virgin 

                MIXTURES, E.G., COMBINE MATERIALS TO DEFINE STAINLESS    Virgin 

                STELL.                                                   Virgin 

                                                                         Virgin 

      IN ORDER TO PLOT THE OUTPUT RESULTS OF THIS CODE USE PROGRAM       Virgin 

      PLOTTAB.                                                           Virgin 

                                                                         Virgin 

      COPIES OF ANY OR ALL OF THESE CODES MAY BE OBTAINED FROM D.E.      Virgin 

      CULLEN AT THE ABOVE ADDRESS.                                       Virgin 

                                                                         Virgin 

      OUTPUT FORMAT                                                      Virgin 

      -------------                                                      Virgin 

      FOR ALL VERSIONS OF THIS PROGRAM PRIOR TO VERSION 92-1 OUTPUT WAS  Virgin 

      IN TABULAR FORM.                                                   Virgin 

                                                                         Virgin 

      FOR VERSION 92-1 AND LATER VERSIONS OF THIS CODE ALL OUTPUT IS IN  Virgin 

      THE PROGRAM PLOTTAB FORMAT TO ALLOW RESULTS TO BE EASILY PLOTTED.  Virgin 

      FOR A COPY OF PROGRAM PLOTTAB CONTACT D.E. CULLEN AT THE ABOVE     Virgin 

      ADDRESS.                                                           Virgin 

                                                                         Virgin 

      TALLY GROUPS                                                       Virgin 

      ------------                                                       Virgin 

      THE TALLY GROUP STRUCTURE MAY BE ANY SET OF MONONTONICALLY         Virgin 

      INCREASING ENERGY BOUNDARIES. THERE MAY BE UP TO 2000 TALLY        Virgin 

      GROUPS. BY USING THE INPUT PARAMETERS THE USER MAY SPECIFY ANY     Virgin 

      ARBITRARY TALLY GROUP STRUCTURE OR SELECT ONE OF THE FOLLOWING     Virgin 

      BUILT-IN GROUP STRUCTURES.                                         Virgin 

                                                                         Virgin 

      (1) TART 175 GROUPS (INPUT  0)                                     Virgin 

      (2) ORNL  50 GROUPS (INPUT -1)                                     Virgin 

      (3) ORNL 126 GROUPS (INPUT -2)                                     Virgin 

      (4) ORNL 171 GROUPS (INPUT -3)                                     Virgin 

      (5) SAND-II 620 GROUPS...UP TO 18 MEV (INPUT -4)                   Virgin 

      (6) SAND-II 640 GROUPS...UP TO 20 MEV (INPUT -5)                   Virgin 

      (7) WIMS 69 GROUPS (INPUT -6)                                      Virgin 

      (8) GAM-I 68 GROUPS (INPUT -7)                                     Virgin 

      (9) GAM-II 99 GROUPS (INPUT -8)                                    Virgin 

     (10) MUFT 54 GROUPS (INPUT -9)                                      Virgin 

     (11) ABBN 28 GROUPS (INPUT -10)                                     Virgin 

                                                                         Virgin 

      INCIDENT SPECTRUM                                                  Virgin 

      -----------------                                                  Virgin 

      THE INCIDENT SPECTRUM MAY BE ANY TABULATED FUNCTION THAT IS        Virgin 

      GIVEN BY A SET OF POINTS THAT IS MONOTONICALLY INCREASING IN       Virgin 

      ENERGY AND LINEAR-LINEAR INTERPOLABLE IN ENERGY-SPECTRUM           Virgin 

      BETWEEN TABULATED POINTS. THERE IS NO LIMIT TO THE NUMBER OF       Virgin 

      POINTS USED TO DESCRIBE THE SPECTRUM. THERE ARE FIVE BUILT-IN      Virgin 

      OPTIONS FOR THE SPECTRUM.                                          Virgin 

                                                                         Virgin 

      (1) CONSTANT...ENERGY INDEPENDENT (INPUT 0)                        Virgin  

      (2) 1/E (INPUT 1)                                                  Virgin 

      (3) BLACKBODY - PHOTON SPECTRUM                                    Virgin 

      (4) BLACKBODY - ENERGY SPECTRUM (E TIMES THE PHOTON SPECTRUM)      Virgin 

      (5) TRANSMITTED SPECTRUM FROM PREVIOUS CASE                        Virgin 

                                                                         Virgin 

      NORMALIZATION OF SPECTRUM                                          Virgin 

      -------------------------                                          Virgin 

      ANY INCIDENT SPECTRUM, EITHER READ AS INPUT OR ONE OF THE          Virgin 

      BUILT-IN SPECTRA, WILL BE NORMALIZED TO UNITY WHEN INTEGRATED      Virgin 

      OVER THEIR ENTIRE ENERGY RANGE.                                    Virgin 

                                                                         Virgin 

      TRANSMITTED SPECTRA WILL NOT BE RE-NORMALIZED, SINCE IT ALREADY    Virgin 

      INCLUDES THE NORMALIZATION OF THE INCIDENT SPECTRUM.               Virgin 

                                                                         Virgin 

      NOTE, INCIDENT SPECTRA IS NORMALIZED TO UNITY OVER THEIR ENTIRE    Virgin 

      ENERGY RANGE - NOT OVER THE ENERGY RANGE OF THE GROUPS. IF THE     Virgin 

      ENERGY RANGE OF THE GROUPS IS LESS THAN THAT OF THE SPECTRUM       Virgin 

      ONLY THAT PORTION OF THE SPECTRUM WILL BE USED AND THIS WILL       Virgin 

      NOT BE RE-NORMALIZED TO UNITY.                                     Virgin 

                                                                         Virgin 

      COMPOSITION OF A LAYER                                             Virgin 

      ----------------------                                             Virgin 

      YOU MAY RUN PROBLEMS INVOLVING                                     Virgin 

      1) A LAYER OF UNIFORM DENSITY - DENSITY FOR ATTENUATION IS THAT    Virgin 

         OF THE TOTAL. DENSITY FOR REACTIONS IS THAT OF THE REACTION.    Virgin 

      2) A LAYER OF UNIFORM DENSITY - DENSITY IS THE SUM OF THE TOTAL    Virgin 

         AND REACTION DENSITIES - THE SUM OF THE CROSS SECTIONS IS       Virgin 

         USED FOR ATTENUATION AND REACTIONS.                             Virgin 

      3) A LAYER OF VARYING DENSITY BASED ON A UNIFORM TOTAL DENSITY     Virgin 

         PLUS A VARIATION BETWEEN 0 AND A MAXIMUM BASED ON THE           Virgin 

         REACTION DENSITY - 0 AT 0 THICKNESS AND MAXIMUM AT MAXIMUM      Virgin 

         THICKNESS. IN THIS CASE THE AVERAGE REACTION DENSITY IS EQUAL   Virgin 

         TO THE INPUT REACTION DENSITY. THE VARIATION IN REACTION        Virgin 

         DENSITY CAN BE LINEAR, SQUARE OR CUBIC.                         Virgin 

      4) A LAYER OF VARYING DENSITY BASED ON A TOTAL DENSITY WHICH       Virgin 

         VARYING FROM MAXIMUM AT 0 THICKNESS TO 0 AT MAXIMUM THICKNESS   Virgin 

         PLUS A REACTION DENSITY WHICH VARIES FROM 0 AT 0 THICKNESS      Virgin 

         TO MAXIMUM AT MAXIMUM THICKNESS. IN THIS CASE THE AVERAGE       Virgin 

         DENSITY OF THE TOTAL AND REACTION WILL BOTH BE EQUAL TO THE     Virgin 

         INPUT TOTAL AND REACTION DENSITIES. THE VARIATION IN TOTAL      Virgin 

         AND REACTION DENSITY CAN BE LINEAR, SQUARE OR CUBIC.            Virgin 

                                                                         Virgin 

      IN THE FIRST CASE THE TWO REQUESTED CROSS SECTIONS ARE CONSIDERED  Virgin 

      TO BE INDEPENDENT - THE TOTAL CROSS SECTION IS USED TO CALCULATE   Virgin 

      ATTENUATION AND THE REACTION CROSS SECTION IS USED TO CALCULATE    Virgin 

      REACTIONS, E.G., TRANSMISSION THROUGH NATURAL URANIUM (THE TOTAL   Virgin 

      CROSS SECTION SHOULD BE THAT OF NATURAL URANIUM) AND REACTIONS     Virgin 

      IN A U-235 DETECTOR (THE REACTION CROSS SECTION SHOULD BE THAT OF  Virgin 

      U-235).                                                            Virgin 

                                                                         Virgin 

      IN THE OTHER THREE CASES THE TWO REQUESTED CROSS SECTIONS ARE      Virgin 

      TREATED AS TWO CONSTITUENTS OF A MIXTURE OF TWO MATERIALS AND      Virgin 

      THE TWO CROSS SECTIONS ARE USED BOTH TO DEFINE A TOTAL CROSS       Virgin 

      SECTION FOR ATTENUATION AND A REACTION CROSS SECTION TO DEFINE     Virgin 

      REACTIONS. IN THESE CASES THE MIXTURE WILL VARY CONTINUOUSLY,      Virgin 

      E.G., IN CASE 4) HALF WAY THROUGH THE LAYER THE COMPOSITION WILL   Virgin 

      BE 1/2 THE MATERIAL DEFINED BY THE TOTAL AND 1/2 THE MATERIAL      Virgin 

      BASED ON THE REACTION. IN THESE CASES RATHER THAN THINKING OF      Virgin 

      THE TWO CROSS SECTIONS AS A TOTAL AND REACTION CROSS SECTION,      Virgin 

      IT IS BETTER TO THINK OF THEM AS THE TOTAL CROSS SECTIONS FOR      Virgin 

      MATERIALS A AND B AND THE CALCULATED REACTIONS WILL BE BASED       Virgin 

      ON THESE TWO TOTAL CROSS SECTIONS.                                 Virgin 

                                                                         Virgin 

      MULTIPLE LAYERS                                                    Virgin 

      ---------------                                                    Virgin 

      THIS CODE MAY BE USED TO RUN EITHER A NUMBER OF INDEPENDENT        Virgin 

      PROBLEMS, EACH INVOLVING TRANSMISSION THROUGH A SINGLE LAYER OF    Virgin 

      MATERIAL, OR TRANSMISSION THROUGH A NUMBER OF LAYERS ONE AFTER     Virgin 

      THE OTHER.                                                         Virgin 

                                                                         Virgin 

      IN THE CASE OF MULTIPLE LAYERS, ONE LAYER AFTER ANOTHER, THE       Virgin 

      TRANSMITTED ENERGY DEPENDENT SPECTRUM IS USED AS THE INCIDENT      Virgin 

      SPECTRUM FOR THE NEXT LAYER. THERE IS NO LIMIT TO THE NUMBER       Virgin 

      OF LAYERS WHICH MAY BE USED - EACH LAYER IS TREATED AS A           Virgin 

      COMPLETELY INDEPENDENT PROBLEM WITH A DEFINED INCIDENT SOURCE,     Virgin 

      AND AS SUCH THE CYCLE OF TRANSMISSION THROUGH EACH LAYER AND       Virgin 

      USING THE TRANSMITTED SPECTRUM AS THE INCIDENT SPECTRUM FOR THE    Virgin 

      NEXT LAYER MAY BE REPEATED ANY NUMBER OF TIMES.                    Virgin 

                                                                         Virgin 

      REMEMBER - THE INCIDENT SPECTRUM IS ASSUMED TO BE LINEARLY         Virgin 

      INTERPOLABLE IN ENERGY AND SPECTRUM BETWEEN THE ENERGIES AT        Virgin 

      WHICH IT IS TABULATED. THE TRANSMITTED SPECTRUM WILL BE TABULATED  Virgin 

      AT THE UNION OF ALL ENERGIES OF THE INCIDENT SPECTRUM AND CROSS    Virgin 

      SECTIONS (TOTAL AND REACTION). IN ORDER TO INSURE THE ACCURACY     Virgin 

      OF THE RESULT WHEN PERFORMING MULTIPLE LAYER CALCULATION BE SURE   Virgin 

      TO SPECIFY THE INCIDENT SPECTRUM ON THE FIRST LAYER TO SUFFICIENT  Virgin 

      DETAIL (ENOUGH ENERGY POINTS CLOSELY SPACED TOGETHER) IN ORDER TO  Virgin 

      ALLOW THE TRANSMITTED SPECTRUM TO BE ACCURATELY REPRESENTED BY     Virgin 

      LINEAR INTERPOLATION BETWEEN SUCCESSIVE ENERGY POINTS - THERE IS   Virgin 

      NO LIMIT TO THE NUMBER OF POINTS ALLOWED IN THE INCIDENT SPECTRUM, Virgin 

      SO IF YOU ARE IN DOUBT, SIMPLY USE MORE ENERGY POINTS TO SPECIFY   Virgin 

      THE INCIDENT SPECTRUM.                                             Virgin 

                                                                         Virgin 

      RESULT OUTPUT UNITS                                                Virgin 

      -------------------                                                Virgin 

      FLUX      = EXACTLY AS CALCULATED                                  Virgin 

      REACTIONS = 1/CM OR 1/GRAM                                         Virgin 

      AVERAGE   = 1/CM - MACROSCOPIC UNITS                               Virgin 

      CROSS                                                              Virgin 

      SECTION                                                            Virgin 

                                                                         Virgin 

      THICKNESS AND DENSITY                                              Virgin 

      ---------------------                                              Virgin 

      THE UNCOLLIDED CALCULATION ONLY DEPENDS ON THE PRODUCT OF          Virgin 

      THICKNESS AND DENSITY (I.E. GRAMS PER CM SQUARED). THIS FACT       Virgin 

      MAY BE USED TO SIMPLIFY INPUT BY ALLOWING THE THICKNESS AND        Virgin 

      DENSITY TO BE GIVEN EITHER AS CM AND GRAMS/CC RESPECTIVELY         Virgin 

      OR ELSE TO GIVE THICKNESS IN GRAMS/(CM*CM) AND INPUT A             Virgin 

      DENSITY OF 1.0 - OR IN ANY OTHER CONVENIENT UNITS AS LONG AS       Virgin 

      THE PRODUCT OF THICKNESS AND DENSITY IS IN THE CORRECT GRAMS       Virgin 

      PER CENTIMETER SQUARED.                                            Virgin 

                                                                         Virgin 

      GRAMS/(CM*CM) ARE RELATED TO ATOMS/BARN THROUGH THE RELATIONSHIP   Virgin 

                                                                         Virgin 

      GRAMS/(CM*CM)=(ATOMS/BARN)*(GRAMS/MOLE)*(MOLE/ATOM)                Virgin 

                                                                         Virgin 

      OR...                                                              Virgin 

                                                                         Virgin 

      GRAMS/(CM*CM)=(ATOMS/BARN)*(ATOMIC WEIGHT)/0.602                   Virgin 

                                                                         Virgin 

      CROSS SECTIONS AT A SPACE POINT AND OPTICAL THICKNESS              Virgin 

      -----------------------------------------------------              Virgin 

      THIS PROGRAM ALLOWS LAYERS OF EITHER UNIFORM DENSITY OR            Virgin 

      CONTINUOUSLY VARYING DENSITY. THE DENSITY CAN BE ONE OF THE        Virgin 

      FOLLOWING FORMS,                                                   Virgin 

      1) C                   = UNIFORM DENSITY                           Virgin 

      2) C*2*(X/T)           = LINEAR VARIATION FROM 0 TO C              Virgin 

      3) C*(2-2*(X/T))       = LINEAR VARIATION FROM C TO 0              Virgin  

      4) C*3*(X/T)**2        = SQUARE VARIATION FROM 0 TO C              Virgin 

      5) C*(3-3*(X/T)**2)/2  = SQUARE VARIATION FROM C TO 0              Virgin 

      6) C*4*(X/T)**3        = CUBIC VARIATION FROM 0 TO C               Virgin 

      7) C*(4-4*(X/T)**3)/3  = CUBIC VARIATION FROM C TO 0               Virgin 

                                                                         Virgin 

      IN ORDER TO CALCULATE REACTIONS AT A POINT THE MICROSCOPIC         Virgin 

      REACTION CROSS SECTION NEED MERELY BE SCALED BY THESE DENSITIES.   Virgin 

                                                                         Virgin 

      IN ORDER TO CALCULATE TRANSMISSION WE MUST DEFINE THE OPTICAL      Virgin 

      PATH LENGTH WHICH MAY BE DEFINED BY INTEGRATING EACH OF THE        Virgin 

      ABOVE DENSITY FORMS TO FIND,                                       Virgin 

      1) C*X                                                             Virgin 

      2) C*X*(X/T)                                                       Virgin 

      3) C*X*(2-(X/T))                                                   Virgin 

      4) C*X*(X/T)**2                                                    Virgin 

      5) C*X*(3-(X/T)**2)/2                                              Virgin 

      6) C*X*(X/T)**3                                                    Virgin 

      7) C*X*(4-(X/T)**3))/3                                             Virgin 

                                                                         Virgin 

      IN ORDER TO CALCULATE TRANSMISSION TO A POINT THE MICROSCOPIC      Virgin 

      TOTAL CROSS SECTION NEED MERELY BE SCALED BY THESE DENSITIES       Virgin 

      TO DEFINE THE OPTICAL PATH LENGTH.                                 Virgin 

                                                                         Virgin 

      THE VARIATION OF THE DENSITY THROUGH THE LAYER MAY BE DEFINED      Virgin 

      BY SETTING X = 0 OR X = T TO FIND,                                 Virgin 

         X = 0      X = T                                                Virgin 

         -----      -----                                                Virgin 

      1) C          C                                                    Virgin 

      2) 0          2*C                                                  Virgin 

      3) 2*C        0                                                    Virgin 

      4) 0          3*C                                                  Virgin 

      5) 3*C/2      0                                                    Virgin 

      6) 0          4*C                                                  Virgin 

      7) 4*C/3      0                                                    Virgin 

                                                                         Virgin 

      THE OPTICAL PATH THROUGH A LAYER OF THICKNESS T MAY BE DEFINED     Virgin 

      FROM THE ABOVE EXPRESSIONS BY SETTING X=T TO FIND THAT IN ALL      Virgin 

      CASES THE ANSWER WILL BY C*T. THE CONSTANTS IN THE ABOVE           Virgin 

      EXPRESSIONS HAVE BEEN INTRODUCED IN ORDER TO FORCE THIS RESULT.    Virgin 

      WITH THESE FACTORS THE OPTICAL PATH LENGTH THROUGH THE LAYER       Virgin 

      WILL EXACTLY CORRESPOND TO AN AVERAGE DENSITY CORRESPONDING TO     Virgin 

      THAT INPUT FOR THE TOTAL AND/OR REACTION, I.E., C CORRESPONDS      Virgin 

      TO THE INPUT DENSITY.                                              Virgin 

                                                                         Virgin 

      NOTE - FOR THE SAME OPTICAL PATH LENGTHS THROUGH THE LAYER THE     Virgin 

      TRANSMISSION WILL BE EXACTLY THE SAME. HOWEVER, VARYING THE        Virgin 

      DENSITY WILL ALLOW YOU TO MODIFY THE REACTION RATES AT SPECIFIC    Virgin 

      DEPTHS INTO THE LAYER.                                             Virgin 

                                                                         Virgin 

      COMPUTATION OF INTEGRALS                                           Virgin 

      ------------------------                                           Virgin 

      STARTING FROM TOTAL CROSS SECTIONS, REACTION CROSS SECTIONS AND    Virgin 

      A SOURCE SPECTRUM ALL OF WHICH ARE GIVEN IN TABULAR FORM WITH      Virgin 

      LINEAR INTERPOLATION BETWEEN TABULATED POINTS ALL REQUIRED         Virgin 

      INTEGRALS CAN BE DEFINED BY ANALYTICAL EXPRESSIONS INVOLVING       Virgin 

      NOTHING MORE COMPLICATED THAN EXPONENTIALS. THE INTEGRALS THAT     Virgin 

      MUST BE EVALUATED ARE OF THE FORM...                               Virgin 

                                                                         Virgin 

      FLUX                                                               Virgin 

      ----                                                               Virgin 

      (INTEGRAL EK TO EK+1) (S(E)* EXP(-XCT(E)*Z)*DE)                    Virgin 

                                                                         Virgin 

      REACTIONS                                                          Virgin 

      ---------                                                          Virgin 

      (INTEGRAL EK TO EK+1) (S(E)*XCR(E)*EXP(-XCT(E)*Z)*DE)              Virgin 

                                                                         Virgin 

      WHERE..                                                            Virgin 

      EK TO EK+1 = LONGEST ENERGY INTERVAL OVER WHICH S(E), XCT(E) AND   Virgin 

                   XCR(E) ARE ALL LINEARLY INTERPOLABLE.                 Virgin 

      S(E)       = ENERGY DEPENDENT WEIGHTING SPECTRUM                   Virgin 

      XCR(E)     = REACTION CROSS SECTION                                Virgin 

      XCT(E)     = OPTICAL PATH LENGTH (BASED ON TOTAL CROSS SECTION)    Virgin 

      Z          = MATERIAL THICKNESS                                    Virgin 

                                                                         Virgin 

      S(E), XCR(E) AND XCT(E) ARE ALL ASSUMED TO BE GIVEN IN TABULAR     Virgin 

      FORM WITH LINEAR INTERPOLATION USED BETWEEN TABULATED POINTS.      Virgin 

      IN OTHER WORDS BETWEEN TABULATED POINTS EACH OF THESE THREE IS     Virgin 

      DEFINED BY A FUNCTION OF THE FORM...                               Virgin 

                                                                         Virgin 

      F(E)=((E - EK)*FK+1 + (EK+1 - E)*FK)/(EK+1 - EK)                   Virgin 

                                                                         Virgin 

      EACH OF THESE THREE CAN BE CONVERTED TO NORMAL FORM BY THE         Virgin 

      CHANGE OF VARIABLES....                                            Virgin 

                                                                         Virgin 

      X=(E - 0.5*(EK+1 + EK))/(EK+1 - EK)                                Virgin 

                                                                         Virgin 

      IN WHICH CASE X WILL VARY FROM -1 (AT EK) TO +1 (AT EK+1) AND      Virgin 

      EACH FUNCTION REDUCES TO THE NORMAL FORM...                        Virgin 

                                                                         Virgin 

      F(X)=0.5*(FK*(1 - X) + FK+1*(1 + X))                               Virgin 

          =0.5*(FK+1 + FK) + 0.5*(FK+1 - FK)*X                           Virgin 

                                                                         Virgin 

      BY DEFINING THE AVERAGE VALUE AND 1/2 THE CHANGE ACROSS THE        Virgin 

      INTERVAL.                                                          Virgin 

                                                                         Virgin 

      AVF=0.5*(FK+1 + FK)                                                Virgin 

      DF= 0.5*(FK+1 - FK)                                                Virgin 

      DE= 0.5*(EK+1 - EK)                                                Virgin 

                                                                         Virgin 

      EACH OF THE THREE FUNCTIONS REDUCES TO THE SIMPLE FORM...          Virgin 

                                                                         Virgin 

      F(X)=AVF+DF*X                                                      Virgin 

                                                                         Virgin 

      AND THE TWO REQUIRED INTEGRALS REDUCE TO...                        Virgin 

                                                                         Virgin 

      FLUX                                                               Virgin 

      ----                                                               Virgin 

      DE*EXP(-AVXCT*Z) * (INTEGRAL -1 TO +1)                             Virgin 

      ((AVS+DS*X)*EXP(-DXCT*Z*X)*DX)                                     Virgin 

                                                                         Virgin 

      REACTION                                                           Virgin 

      --------                                                           Virgin 

      DE*EXP(-AVXCT*Z) * (INTEGRAL -1 TO +1)                             Virgin 

      ((AVS*AVXCR+(AVS*DXCR+AVXCR*DS)*X+DS*DXCR*X*X)*EXP(-DXCT*Z*X)*DX)  Virgin 

                                                                         Virgin 

      WHERE                                                              Virgin 

                                                                         Virgin 

      AVXCT   = AVERAGE VALUE OF THE TOTAL CROSS SECTION                 Virgin 

      AVXCR   = AVERAGE VALUE OF THE REACTION CROSS SECTION              Virgin 

      AVS     = AVERAGE VALUE OF THE SOURCE                              Virgin 

      DXCT    = 1/2 THE CHANGE IN THE TOTAL CROSS SECTION                Virgin 

      DXCR    = 1/2 THE CHANGE IN THE REACTION CROSS SECTION             Virgin 

      DS      = 1/2 THE CHANGE IN THE SOURCE                             Virgin 

      DE      = 1/2 THE CHANGE IN THE ENERGY                             Virgin 

                                                                         Virgin 

      NOTE THAT IN THIS FORM THE ENERGY ONLY APPEARS IN FRONT OF THE     Virgin 

      INTEGRALS AND THE INTEGRALS ARE EXPRESSED ONLY IN TERMS OF THE     Virgin 

      TABULATED VALUES OF S(E), XCT(E) AND XCR(E). IN PARTICULAR NO      Virgin  

      DERIVATIVES ARE USED, SO THAT THERE ARE NO NUMERICAL INSTABILITY   Virgin 

      PROBLEMS IN THE VACINITY OF DISCONTINUITIES IN S(E), XCT(E) OR     Virgin 

      XCR(E). INDEED, SINCE (EK+1 - EK) APPEARS IN FRONT OF THE INTEGRAL Virgin 

      POINTS OF DISCONTINUITY AUTOMATICALLY MAKE ZERO CONTRIBUTION TO    Virgin 

      THE INTEGRALS.                                                     Virgin 

                                                                         Virgin 

      THE REQUIRED INTEGRALS CAN BE EXPRESSED IN TERMS OF THE THREE      Virgin 

      INTEGRALS IN NORMAL FORM....                                       Virgin 

                                                                         Virgin 

      F(A,N) = (INTEGRAL -1 TO 1) (X**N*EXP(-A*X)*DX), N=0,1 AND 2.      Virgin 

                                                                         Virgin 

      THESE THREE INTEGRALS CAN BE EVALUATED TO FIND...                  Virgin 

                                                                         Virgin 

      N=0                                                                Virgin 

      ---                                                                Virgin 

      F(A,0) = (EXP(A)-EXP(-A))/A                                        Virgin 

                                                                         Virgin 

      N=1                                                                Virgin 

      ---                                                                Virgin 

      F(A,1) = ((1-A)*EXP(A)-(1+A)*EXP(-A))/(A*A)                        Virgin 

                                                                         Virgin 

      N=2                                                                Virgin 

      ---                                                                Virgin 

      F(A,2) = ((2-2*A+A*A)*EXP(A)-(2+2*A+A*A)*EXP(-A))/(A*A*A)          Virgin 

                                                                         Virgin 

      HOWEVER THESE EXPRESSIONS ARE NUMERICALLY UNSTABLE FOR SMALL       Virgin 

      VALUES OF A. THEREFORE FOR SMALL A THE EXPONENTIAL IN THE          Virgin 

      INTEGRALS ARE EXPANDED IN A POWER SERIES...                        Virgin 

                                                                         Virgin 

      EXP(-AX)=1.0-(AX)+(AX)**2/2-(AX)**3/6+(AX)**4/24-........          Virgin 

              =(SUM K=0 TO INFINITY) (-AX)**K/(K FACTORIAL)              Virgin 

                                                                         Virgin 

      AND THE INTEGRAL REDUCES TO THE FORM....                           Virgin 

                                                                         Virgin 

      (SUM K=0 TO INFINITY) ((-A)**K/(K FACTORIAL)) *                    Virgin 

      (INTEGRAL -1 TO 1) (X**(N+K))*DX                                   Virgin 

                                                                         Virgin 

      WHICH CAN BE ANALYTICALLY EVAULATED TO FIND....                    Virgin 

      (K(N) = K FACTORIAL)                                               Virgin 

                                                                         Virgin 

      N=0                                                                Virgin 

      ---                                                                Virgin 

      F(A,0) = 2*(1+(A**2)/K(3)+(A**4)/K(5)+(A**6)/K(7)+....             Virgin 

                                                                         Virgin 

      N=1                                                                Virgin 

      ---                                                                Virgin 

      F(A,1) = -2*A*(2/K(3)+4*(A**2)/K(5)+6*(A**4)/K(7)+8*(A**6)/K(9)+.. Virgin 

                                                                         Virgin 

      N=2                                                                Virgin 

      ---                                                                Virgin 

      F(A,2) = 2*(2/K(3)+3*4*(A**2)/K(5)+5*6*(A**4)/K(7)+                Virgin 

               7*8*(A**6)/K(9)+....                                      Virgin 

                                                                         Virgin 

      THESE EXPANSIONS ARE USED WHEN THE ABSOLUTE VALUE OF A IS LESS     Virgin 

      THAN 0.1. BY TRUNCATING THE ABOVE SERIES BEFORE A**8 THE ERROR     Virgin 

      RELATIVE TO THE LEADING TERM OF THE SERIES WILL BE 10**(-10),      Virgin 

      YIELDING 10 DIGIT ACCURACY.                                        Virgin 

                                                                         Virgin 

      AFTER EVALUATING THE ABOVE FUNCTIONS, EITHER DIRECTLY OR BY USING  Virgin 

      THE EXPANSION THE TWO REQUIRED INTEGRALS CAN BE WRITTEN AS...      Virgin 

                                                                         Virgin 

      FLUX                                                               Virgin 

      ----                                                               Virgin 

      DE*EXP(-AVXCT*Z)*(AVS*F(A,0) + DS*F(A,1))                          Virgin 

                                                                         Virgin 

      REACTIONS                                                          Virgin 

      ---------                                                          Virgin 

      DE*EXP(-AVXCT*Z)*                                                  Virgin 

      (AVS*AVXCR*F(A,0) + (AVS*DXCR+AVXCR*DS)*F(A,1) + DS*DXCR*F(A,2))   Virgin 

                                                                         Virgin 

      INPUT FILES                                                        Virgin 

      -----------                                                        Virgin 

      FILENAME  UNIT  DESCRIPTION                                        Virgin 

      --------  ----  -----------                                        Virgin 

      INPUT       2   INPUT LINES                                        Virgin 

      ENDFIN     10   EVALUATED DATA IN ENDF/B FORMAT                    Virgin 

                                                                         Virgin 

      OUTPUT FILES                                                       Virgin 

      ------------                                                       Virgin 

      FILENAME  UNIT  DESCRIPTION                                        Virgin 

      --------  ----  -----------                                        Virgin 

      OUTPUT      3   OUTPUT LISTING                                     Virgin 

                                                                         Virgin 

      SCRATCH FILES                                                      Virgin 

      -------------                                                      Virgin 

      FILENAME  UNIT  DESCRIPTION                                        Virgin 

      --------  ----  -----------                                        Virgin 

      SCR1       12   REACTION, FLUX AND CROSS SECTION RESULTS (BCD)     Virgin 

                      (SORTED AT END OF RUN AND OUTPUT SEPARATELY)       Virgin 

      SCR2       13   TALLY GROUP ENERGY BOUNDARIES (BINARY)             Virgin 

      SCR3       14   SOURCE SPECTRUM (BINARY)                           Virgin 

      SCR4       15   TOTAL CROSS SECTION (BINARY)                       Virgin 

      SCR5       16   REACTION CROSS SECTION (BINARY)                    Virgin 

                                                                         Virgin 

      OPTIONAL STANDARD FILE NAMES (SEE SUBROUTINE FILIO1 AND FILEIO2)   Virgin 

      ----------------------------------------------------------------   Virgin 

      UNIT  FILE NAME   FORMAT                                           Virgin 

      ----  ----------  ------                                           Virgin 

        2   VIRGIN.INP   BCD                                             Virgin 

        3   VIRGIN.LST   BCD                                             Virgin 

       10   ENDFB.IN     BCD                                             Virgin 

     11-15  (SCRATCH)   BINARY                                           Virgin 

       16   PLOTTAB.CUR PLOTTAB OUTPUT FORMAT DATA                       Virgin 

                                                                         Virgin 

      INPUT LINES                                                        Virgin 

      -----------                                                        Virgin 

      ANY NUMBER OF CASES MAY BE RUN ONE AFTER THE OTHER. AFTER THE      Virgin 

      FIRST CASE HAS BEEN RUN THE FOLLOWING CASES MAY USE THE SAME       Virgin 

      THICKNESSES, GROUP STRUCTURE AND SPECTRUM AS THE PRECEDING CASE.   Virgin 

      IN ADDITION THE TRANSMITTED SPECTRUM FROM ONE CASE MAY BE USED     Virgin 

      AS THE INCIDENT SPECTRUM IN THE NEXT CASE, TO ALLOW MULTIPLE       Virgin 

      LAYERS OF DIFFERENT MATERIALS.                                     Virgin 

                                                                         Virgin 

      LINE  COLS.  FORMAT  DESCRIPTION                                   Virgin 

      ----  -----  ------  ----------                                    Virgin 

         1   1-60   ENDF/B INPUT DATA FILENAME                           Virgin 

                      (STANDARD OPTION = ENDFB.IN)                       Virgin 

                                                                         Virgin 

      LEAVE THE DEFINITION OF THE FILENAMES BLANK - THE PROGRAM WILL     Virgin 

      THEN USE STANDARD FILENAMES.                                       Virgin 

                                                                         Virgin 

       2-3   1-72   18A4   TWO LINE TITLE DESCRIBING PROBLEM             Virgin 

         4   1- 6    I6    ZA (1000*Z+A) OF TARGET FOR TOTAL             Virgin 

             7-11    I5    MT OF TOTAL                                   Virgin 

            12-22   E11.4  DENSITY FOR TOTAL                             Virgin 

            23-28    I6    ZA (1000*Z+A) OF TARGET FOR REACTION          Virgin 

            29-33    I5    MT OF REACTION                                Virgin 

                           = 0 - NO REACTION CALCULATION (ONLY FLUX).    Virgin  

                           = GREATER THAN 0 - CALCULATE REACTIONS.       Virgin 

            34-44   E11.4  DENSITY FOR REACTION                          Virgin 

            45-50    I6    NUMBER OF TARGET THICKNESSES                  Virgin 

                           = GREATER THAN 0 = READ FROM INPUT            Virgin 

                             (1 TO 2000 ALLOWED)                         Virgin 

                           =  0 = SAME AS LAST CASE                      Virgin 

            51-55    I5    NUMBER OF TALLY GROUPS                        Virgin 

                           (REMEMBER NUMBER OF GROUP BOUNDARIES          Virgin 

                           IS ONE MORE THAN THE NUMBER OF GROUPS)        Virgin 

                           UP TO 2000 GROUPS ARE ALLOWED                 Virgin 

                           BUILT-IN GROUP STRUCTURES.                    Virgin 

                           = GREATER THAN 0 = READ FROM INPUT            Virgin 

                           =  0 SAME AS LAST CASE                        Virgin 

                           = -1 TART 175 GROUPS                          Virgin 

                           = -2 ORNL  50 GROUPS                          Virgin 

                           = -3 ORNL 126 GROUPS                          Virgin 

                           = -4 ORNL 171 GROUPS                          Virgin 

                           = -5 SAND-II 620 GROUPS..UP TO 18 MEV.        Virgin 

                           = -6 SAND-II 640 GROUPS..UP TO 20 MEV.        Virgin 

                           = -7 WIMS 69 GROUPS                           Virgin 

                           = -8 GAM-I 68 GROUPS                          Virgin 

                           = -9 GAM-II 99 GROUPS                         Virgin 

                           =-10 MUFT 54 GROUPS                           Virgin 

                           =-11 ABBN 28 GROUPS                           Virgin 

            56-60    I5    NUMBER OF POINTS IN SOURCE SPECTRUM           Virgin 

                           (MUST BE AT LEAST TWO POINTS)                 Virgin 

                           = GREATER THAN 1 = READ FROM INPUT            Virgin 

                           =  0 = SAME AS LAST CASE                      Virgin 

                           = -1 = CONSTANT (ENERGY INDEPENDENT)          Virgin 

                           = -2 = 1/E                                    Virgin 

                           = -3 = BLACKBODY - PHOTON SPECTRUM            Virgin 

                           = -4 = BLACKBODY - ENERGY SPECTRUM            Virgin 

                           = -5 = TRANSMITTED SPECTRUM FROM LAST CASE    Virgin 

                           NOTE, ALL SPECTRA, EXCEPT THE TRANSMITTED     Virgin 

                           SPECTRUM FROM THE LAST CASE, WILL BE          Virgin 

                           NORMALIZED SUCH THAT ITS INTEGRAL OVER        Virgin 

                           ENERGY WILL BE UNITY.                         Virgin 

            61-64  1X,3I1  SPATIALLY DEPENDENT OUTOUT                    Virgin 

                           = 0 = NO                                      Virgin 

                           = 1 = YES                                     Virgin 

                           FOR THE 3 QUANTITIES                          Virgin 

                           COLUMN 67 FLUX                                Virgin 

                                  68 REACTIONS                           Virgin 

                                  69 AVERAGE CROSS SECTION               Virgin 

            65-65    I1    ENERGY DEPENDENT OUTOUT                       Virgin 

                           = 0 = NONE                                    Virgin 

                           = 1 = INCIDENT SPECTRUM                       Virgin 

                           = 2 = TRANSMITTED SPECTRUM                    Virgin 

                           = 3 = INCIDENT REACTIONS                      Virgin 

                           = 4 = TRANSMIITED REACTIONS                   Virgin 

                           = 5 = TOTAL CROSS SECTION                     Virgin 

                           = 6 = REACTION CROSS SECTION                  Virgin 

         5   1-11   E11.4  BLACKBODY TEMPERATURE IN EV                   Virgin 

            12-22   E11.4  FLUX NORMALIZATION                            Virgin 

            23-33   E11.4  REACTION NORMALIZATION                        Virgin 

                           CALCULATIONS WILL BE BASED ON THE SPECTRUM    Virgin 

                           AND CROSS SECTIONS AS READ. AT OUTPUT THE     Virgin 

                           RESULTS WILL BE MULTIPLIED BY THESE           Virgin 

                           NORMALIZATION FACTORS.                        Virgin 

            34-44    I11   DENSITY PROFILE                               Virgin 

                           = 0 - UNIFORM - BASED ON TOTAL DENSITY        Virgin 

                           = 1 - UNIFORM - TOTAL + REACTION DENSITY      Virgin 

                           = 2 - TOTAL + LINEAR REACTION                 Virgin 

                           = 3 - LINEAR (TOTAL + REACTION)               Virgin 

                           = 4 - TOTAL + SQUARE REACTION                 Virgin 

                           = 5 - SQUARE (TOTAL + REACTION)               Virgin 

                           = 6 - TOTAL + CUBIC REACTION                  Virgin 

                           = 7 - CUBIC (TOTAL + REACTION)                Virgin 

       6-N   1-66  6E11.4  TARGET THICKNESSES IN CM                      Virgin 

                           IF SAME AS LAST CASE THIS SECTION IS NOT      Virgin 

                           INCLUDED IN THE INPUT.                        Virgin 

      VARY   1-66  6E11.4  TALLY GROUP ENERGY BOUNDARIES                 Virgin 

                           (NUMBER OF BOUNDARIES IS ONE MORE THAN        Virgin 

                           THE NUMBER OF TALLY GROUPS)                   Virgin 

                           IF THE STANDARD OPTION (-11 TO 0) IS          Virgin 

                           SELECTED THIS SECTION IS NOT INCLUDED         Virgin 

                           IN THE INPUT                                  Virgin 

      VARY   1-66  6E11.4  SOURCE SPECTRUM IN ENERGY (EV)-SOURCE PAIRS   Virgin 

                           (MUST BE AT LEAST TWO POINTS)                 Virgin 

                           IF STANDARD OPTION (-5 TO 0) IS SELECTED THIS Virgin 

                           SECTION IS NOT INCLUDED IN THE INPUT          Virgin 

                                                                         Virgin 

      ANY NUMBER OF CASES MAY BE RUN ONE AFTER ANOTHER.                  Virgin 

                                                                         Virgin 

      EXAMPLE INPUT NO. 1                                                Virgin 

      -------------------                                                Virgin 

      CALCULATE THE UNCOLLIDED FLUX AND CAPTURE (MT=102) THROUGH         Virgin 

      30 CM OF IRON (DENSITY 7.87 G/CC). TALLY THE RESULTS USING         Virgin 

      THE TART 175 GROUP STRUCTURE. THE SOURCE WILL BE CONSTANT          Virgin 

      FROM 1 KEV TO 20 MEV. USE THE STANDARD ENDF/B INPUT DATA           Virgin 

      FILENAME.                                                          Virgin 

                                                                         Virgin 

      ENDFB.IN                                                           Virgin 

      IRON 0 TO 30 CM THICK.                                             Virgin 

      CONSTANT SOURCE FROM 1 KEV TO 20 MEV.                              Virgin 

       26000    1 7.87000+ 0 26000  102 7.87000+ 0     2    0    2 1100  Virgin 

       0.00000+ 0 1.00000+ 0 1.00000+ 0          0 0.00000+00            Virgin 

       0.00000+00 3.00000+01                                             Virgin 

       1.0000E+03 1.0000E+00 2.0000E+07 1.0000E+00                       Virgin 

                                                                         Virgin 

      EXAMPLE INPUT NO. 2                                                Virgin 

      -------------------                                                Virgin 

      CALCULATE THE UNCOLLIDED PHOTON FLUX THROUGH A MIXTURE OF SILICON  Virgin 

      AND IRON FOR 100 MEV PHOTONS INCIDENT. THE TRANSMISSION WILL BE    Virgin 

      CALCULATED FOR 21 THICKNESSES VARYING BETWEEN 0 AND 1 CM. THERE    Virgin 

      WILL BE ONLY 1 TALLY GROUP SPANNING A VERY NARROW ENERGY RANGE     Virgin 

      NEAR 100 MEV, AND THE SOURCE SPECTRUM WILL BE CONSTANT OVER THE    Virgin 

      SAME ENERGY RANGE. USE THE STANDARD ENDF/B INPUT DATA FILENAME     Virgin 

      BY LEAVING THE FIRST INPUT LINE BLANK.                             Virgin 

                                                                         Virgin 

      (THIS IS A BLANK LINE TO USE THE STANDARD INPUT FILENAME)          Virgin 

      100 MEV PHOTONS                                                    Virgin 

      SILICON + 5 % IRON                                                 Virgin 

       14000  521 2.30000+ 0 26000  521 1.15000- 1    21    1    2 1000  Virgin 

       0.00000+ 0 1.00000+ 0 1.00000+ 0          1 0.00000+00            Virgin 

       0.00000+00 5.00000-01 1.00000+00 1.50000+00 2.00000+00 2.50000+00 Virgin 

       3.00000+00 3.50000+00 4.00000+00 4.50000+00 5.00000+00 5.50000+00 Virgin 

       6.00000+00 6.50000+00 7.00000+00 7.50000+00 8.00000+00 8.50000+00 Virgin 

       9.00000+00 9.50000+00 1.00000+01                                  Virgin 

       9.99000+ 7 1.00100+ 8                                             Virgin 

       9.99000+ 7 1.00000+ 4 1.00100+ 8 1.00000+ 4                       Virgin 

                                                                         Virgin 

 ======================================================================= Virgin