"user manual"
Contents
1. Card COMP 1 COMP 2 COMP 3 COMP 4 Card COMP 1 COMP 2 COMP 3 COMP 4 Additional Examples cont Material Mixture is lead glass consisting of five specified elements 1 per cent trace elements unspecified Density effect calculated by Sternheimer Peierls 123456789112345678921234567893123456789412345678 etc MIXT amp INP NE 5 RHO 3 61 RHOZ 41 8 21 0 29 0 5 0 2 2 amp END LEAD GLASS PB SIO K NA 123456789112345678921234567893123456789412345678 etc COMP amp INP NE 3 RHO 7 13 PZ 4 3 12 amp END BGO BI GE O 123456789112345678921234567893123456789412345678 etc COMP SINP NE 2 RHO 7 08E 2 PZ 1 1 amp END LIQUID HYDROGEN H2 LIQUID H H Using PEGS4 The ENER Option ENER1 4A1 OPT 1 4 ENER Means select energy limits ENER2 NAMELIST INP AE Lower cutoff energy total for charged particle trans port MeV UE Upper limit energy total for charged particle trans port MeV AP Lower cutoff energy for photon transport MeV UP Upper limit energy for photon transport MeV Note If the user supplies negative values for the energy limits above the absolute values given will be interpreted as in units of the electron rest mass energy Thus AE 1 is equivalent to AE 0 511 MeV The following card setup illustrates how to use ENER option 123456789112345678921234567893123456789412345678 etc 1 ENER 2 amp INP AE 0 521 UE 100 AP 0 001 UP 100 amp END Using PEGS2. 5 57090E 00 RHOZ 7 80300E 01 ASYM O Z 8 A 15 999 PZ 1 31442E 00 RHOZ 2 10300E 01 ASYM AR Z 18 A 39 948 PZ 2 35306E 02 RHOZ 9 40000E 01 3 05535E 04 1 50000E 00 1 00000E 01 1 00000E 05 1 00000E 05 o 200 o 150 0 0 0 0 0 9 99983E 01 2 10279E 01 4 82540E 02 9 95882E 01 2 25707E 0O1 500 or more cards follow Using PEGS4 s PEGS4 Output cont MEDIUM ISOOCTANE STERNCID ISOOCTANE COMP RHO 6 9190E 01 NE 2 ASYM C Z 6 A 12 011 PZ 8 00000E 00 RHOZ 9 60892E 01 ASYM H Z 1 A 1 008 PZ 1 80000E 01 RHOZ 1 81434E 01 6 50520E 01 5 21000E 01 1 00000E 02 5 05110E 01 5 00000E 01 0 199 0 149 0 0 0 0 0 9 99983E 01 2 04659E 01 4 69644E 02 9 95992E 01 2 19675E 01 500 or more cards follow MEDIUM AU USING NEW PEGS4N STERNCID AU ELEM RHO 1 9300E 01 NE 1 IUNRST 0 EPSTFL 0 IAPRIM 1 ASYM AU Z 79 A 196 987 PZ 1 00000E 00 RHOZ 1 96987E 02 3 34846E 01 5 21000E 01 1 00000E 03 1 00000E 01 1 00000E 01 0 199 0 150 0 0 0 1 0 9 99979E 01 2 53604E 01 5 81963E 02 9 95034E 01 2 72211E 01 500 or more cards follow Using PEGS4 CALL1 4A1 OPT 1 4 CALL2 NAMELIST INP XP 1 4 The CALL Option CALL Means Call the designated function and print value Values for up to four argu ments of the function e The following card setup illustrates the CALL option 123456789112345678921234567893123456789412345678 etc ELEM amp INP amp END PB PB CALL amp INP XP 1 49 99 amp END GMFP
3. ai i Using PEGS4 The MIXT Option 1 of 2 MIXT1 4A1 OPT 1 4 MIXT Means select mat erial that is a mixture MIXT2 NAMELIST INP NE Number of elements in mixture RHO Density g cm 3 of mixture at NTP for gases RHOZ I I 1 NE Relative amount of atom in mixture by weight GASP Optional Defines state of mixture zero default for solid or liquid otherwise value gives gas pressure atm WA I I 1 NE Optional May be used to override default atomic weights IRAYL Optional Set to unity to included Rayleigh output IUNRST Same as for ELEM2 ISSB Same as for ELEM2 EPSTFL Same as for ELEM2 IAPRIM Same as for ELEM2 MIXT3 24A1 MEDIUM IDSTRN Same as for ELEM3 6X 24A1 MIXT4 24 A2 ASYM I I 1 NE Same as for COMP4 Using PEGS4 1X The MIXT Option 2 of 2 The following card setup illustrates how to use the MIXT option Column 123456789112345678921234567893123456789412345678 etc 1 MIXT 2 amp INP NE 7 RHO 2 26 RHOZ 49 83 1 71 4 56 31 58 1 92 8 26 1 22 amp END 3 CONCRETE 4 O NA AL SI K CA FE There are 7 elements and the density is 2 26 g cm The relative amount of each atom by weight is written in the simple form RHOZ 49 83 1 17 etc The 24 character string CONCRETE iis selected to be the identifier used in subsequent EGS runs No character string was chosed for the Sternheimer identifier so PEGS4 will set equal to CONCRETE and this will not be found in
4. documentation for the parameters IUNRST EPSTFL and IAPRIM Using PEGS4 Logical Relationship Between the Options of PEGS4 Using PEGS4 The ELEM COMP and MIXT Options The purpose of the ELEMent COMPound and MIxXTure options is to specify the material s used by the PEGS4 functions e Parameters needed to specify a material are Density RHO Number of different kinds of elements NE Atomic number of each kind Z T Atomic weight of each kind WA I Proportion of each kind e By number PZ I for compounds e By weight RHOZ I for mixtures e PEGS4 has tables for for elements I 1 through 100 The atomic symbol ASYM 1 100 The atomic weight WATBL 1 100 e PEGS4 also has a table of the densities of the elements RHOTBL 1 100 e For each option there is an associated table that we will discuss in turn next Using PEGS4 The ELEM Option 1 of 3 FORMAT VARIABLES READ COMMENTS ELEM1 4A1 OPT 1 4 ELEM Means select mat erial that is an element ELEM2 NAMELIST INP RHO Optional If given this overrides the PEGS default density g cm 3 for the element WA 1 Optional Atomic weight of element If given this overrides the PEGS default IRAYL Optional Set to unity to included Rayleigh output IUNRST Optional Set to unity for unrestricted collision stop ping power ISSB Optional Set to unity to use own density effect param eters see text below EP
5. the SSB table so the approximation scheme will be used The atomic symbols for the elements are specified in the fourth MIXT card again pay attention to the format 24 A2 1X Using PEGS4 Additional Examples Material Element is liquid Helium 3 Density and atomic weight overridden by user Note that HELIUM 3 will not be found in SSB tables Card 123456789112345678921234567893123456789412345678 etc ELEM1 ELEM ELEM2 amp INP RHO 0 178 WA 1 3 amp END ELEM3 HELIUM 3 ELEM4 HE Material Compound is Nitrogen gas a diatomic molecule Density and gas pressure overridden by user Card 123456789112345678921234567893123456789412345678 etc COMP 1 COMP COMP 2 amp INP NE 2 PZ 1 1 RHO 0 808 GASP 2 amp END COMP3 NITROGEN 2 ATM N2 GAS COMP 4 N N Using PEGS4 Additional Examples cont Material Compound is sodium iodide with IDSTRN 1 24 defaulting to MEDIUM 1 24 but NAI will be found in SSB tables Card 123456789112345678921234567893123456789412345678 etc COMP 1 COMP COMP 2 amp INP NE 2 RHO 3 667 PZ 1 1 P2Z 2 1 amp END COMP 3 NAI COMP 4 NA I Material Compound is Pilot B scintillator Data taken from Physics Letters B204 April 1988 density 1 032 atomic ratio H C 1 10 Material is in SSB table Card 123456789112345678921234567893123456789412345678 etc COMP 1 COMP COMP 2 amp INP NE 2 RHO 1 032 PZ 1 1 P2 2 1 10 amp END COMP 3 PILOT B POLYSTYRENE COMP 4 C H Using PEGS4
6. 4 The Options PWLF and DECK e The minimal data setup for PEGS4 consists of choosing ELEM Or MIXT or COMP followed by ENER and then followed by PWLF and DECK e For the general case the PWLF and DECK options are very trivial but necessary they consist of the option name followed by a blank NAMELIST read card amp INP amp END Using PEGS4 The Options PWLF and DECK cont e Together with one of the above examples the entire card card setup might consist of the following ten cards for BGO detector 123456789112345678921234567893123456789412345678 etc COMP amp INP NE 3 RHO 7 13 PZ 4 3 12 amp END BGO BI GE O ENER amp INP AE 0 521 UE 100 AP 0 001 UP 100 amp END PWLF amp INP amp END DECK amp INP amp END oO Cc 1 6 OClab GW N eA p e The TEST option is also available for obtaining plots of all functions that the PWLF option fits Using PEGS4 Examples of PEGS4 Output MED IUM WOOD STERNCID WOOD COMP RHO 5 0000E 01 NE 3 ASYM C Z 6 A 12 011 PZ 6 00000E 00 RHOZ 7 20669E 01 ASYM H Z 1 A 1 008 PZ 5 00000E 00 RHOZ 5 03985E 00 ASYM O Z 8 A 15 999 PZ 5 00000E 00 RHOZ 7 99970E 01 7 65637E 01 5 21000E 01 1 00000E 02 5 05110E 01 5 00000E 01 0 199 0 149 0 0 0 1 0 9 99983E 0O1 2 09272E 01 4 80231E 02 9 95902E 01 2 24627E 0O1 500 or more cards follow MEDIUM AIR AT NTP STERNCID AIR GAS MIXT RHO 1 2050E 03 NE 3 GASP 1 0000E 00 ASYM N Z 7 A 14 007 PZ
7. CALL amp INP XP 1 50 01 amp END GMFP ow O Ii Oo OL WN e ji which produces the following PEGS4 output 1 95522 1 97485 FUNCTION CALL FUNCTION CALL 49 9900 50 0100 GMFP OF GMFP OF Using PEGS4
8. NRG CNRS PEGS4 Walter R Nelson Stanford Linear Accelerator Center Introduction e Primary purpose of PEGS4 is to create material data sets for subsequent use by EGSnrc and EGS4 of course e Operations necessary to accomplish this task include Selection of materials Selection of energy cutoffs Piecewise linear fitting Creation of output data set for direct use by EGSnrc Using PEGS4 Introduction cont e PEGS4 can provide other services too such as Production of print plots of selected functions Evaluation of functions at selected points Comparison of functions with sampled spectra In this lecture we will learn how to create media data sets e We will also take a quick look at some other PEGS4 Services Using PEGS4 The PEGS4 Connection to EGSnrc e PEGS4 has been modified very little for use with EGSnrc However the EGSnrc code has new features that require considerably more data than provided by the PEGS4 code and this data is read in directly by means of the EGSnrc version of SUBROUTINE HATCH Using PEGS4 PEGS4 Documentation The PEGS4 User Manual is provided in Chapter 6 of the EGSnrc manual tis essentially a reprint of the original PEGS4 manual for the EGS4 Code System i e Appendix 3 of SLAC265 e However a few additions have been made to PEGS4 since 1985 and these are explained at the beginning of Chapter 6 e Of particular note is the
9. STFL Optional Set to unity for ICRU 37 collision stopping power IAPRIM Optional Set to unity to normalize bremsstrahlung cross section to ICRU 37 radiative stopping power Using PEGS4 The ELEM Option 2 of 3 FORMAT VARIABLES READ COMMENTS ELEM3 24Al1 MEDIUM 1 24 Identifier assigned to data 6X 24A1 set to be produced IDSTRN 1 24 Optional Identifer of medium name under which desired Sternheimer Seltzer Berger coeffcients are given in PEGS If not specified the identifier in MEDIUM 1 24 is used ELEM4 24 A2 1X ASYM 1 Atomic symbol for element It should be noted that when setting EPSTFL 1 in NAMELIST INP the NRC scripts require that a file containing the ICRU 37 collision stopping powers be identified on the command line invoking the script Using PEGS4 The ELEM Option 3 of 3 The following card setup illustrates how to use the ELEM option Column 123456789112345678921234567893123456789412345678 etc ELEM amp INP IAPRIM 1 IRAYL 1 amp END PB 10 KEV TO 100 MEV PB PB IAPRIM set to unity invokes option to normalize the bremsstrahlung cross section radiative stopping power will be same as CRU 37 DWN H IRAYL is set to unity Rayleigh scattering included in PEGS4 output note user must still turn it on off in User Code The 24 character string PB 10 KEV TO 100 MEV is selected to be the identifier used in subsequent EGS runs PEGS4 will search for any Sternheimer
10. Seltzer_Berger coefficients identified by the 24 character string PB Since no other quantities have been added to the NAMELIST INP i e between the amp INP and amp END delimiters the default values for RHO etc will be used for the element PB Using PEGS4 Sternheimer Seltzer Berger SSB Coefficients The density effect in the dE dx Bethe Bloch formula Treated extensively for many years by Sternheimer A general formula is used and is given in terms of Sternheimer parameters A set of density effect parameters have been created by SSB They are tabulated for 73 materials in PEGS4 see Table 2 13 2 of SLAC 265 p 71 72 The string IDSTRN 1 24 is used in order to make use of SSB density effect parameters If IDSTRN 1 is blank then IDSTRN 1 24 is given the same name as MEDIUM 1 24 If IDSTRN 1 24 cannot be found inthe BLOCK DATA the density effect is calculated from another general formula by Sternheimer and Pereris Users can also supply their own SSB parameters by setting ISSB to unity Using PEGS4 The comp Option 1 of 3 FORMAT VARIABLES READ COMMENTS COMP 1 4A1 OPT 1 4 COMP Means select mat erial that is a compound COMP2 NAMELIST INP NE Number of elements in compound RHO Density g cm 3 of compound at NTP for gases PZ I I 1 NE Relative numbers of atoms in compound GASP Optional Defines state of compound zero default for solid or liquid o
11. therwise value gives gas pressure atm WA I I 1 NE Optional May be used to override default atomic weights e g to allow for special isotopes IRAYL Same as for ELEM2 IUNRST Same as for ELEM2 ISSB Same as for ELEM2 EPSTFL Same as for ELEM2 IAPRIM Same as for ELEM2 Using PEGS4 The comp Option 2 of 3 FORMAT VARIABLES READ COMMENTS COMP3 24Al1 MEDIUM IDSTRN Same as for ELEM3 6X 24A1 COMP4 24 A2 ASYM I I 1 NE Atomic symbols for the atoms 1X in the compound Duplicates are allowed if several iso topes of the same element are present or may be required for diatomic molecules e g nitrogen gas Using PEGS4 The comp Option 3 of 3 The following card setup illustrates how to use the COMP option Column 123456789112345678921234567893123456789412345678 etc 1 COMP 2 SINP NE 2 PZ 2 1 RHO 1 0 IAPRIM 1 amp END 3 WATER H20 4 H O The number of elements in the compound NE is 2 The relative number of atoms in H O is PZ 2 1 we also could have written this out more specifically in the form PZ 1 2 PZ 2 1 The density is the standard RHO 1 0 but you must state what it is 1 e it is not optional The 24 character string WATER is selected to be the identifier used in subsequent EGS runs PEGS4 will search for any Sternheimer Seltzer_Berger coefficients identified by the 24 character string H20 i The atomic symbols are H and O note the order and the format
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