Empirical MACs

EPMA Xtreme Probe

 

Probe Menu Details > Analytical

Empirical MACs

This menu allows the user to selectively load empirical MACs (mass absorption coefficients) from a supplied ASCII file or data entry.

Empirical MAC (Mass Absorption Coefficients) are stored in a file called EMPMAC.DAT in the Probe for EPMA program data directory (usually C: \ProgramData\Probe Software\Probe for EPMA). If the user obtains any new empirical MAC data the file can be edited using any text editor such as NotePad or TextPad. Be careful to avoid adding any <tab> characters when editing the file (use space or comma delimited values only). The values can then be accessed using from the Analytical | Empirical MACs menu for runs that contains a matching emitter and absorber binary. Any changes to the default MAC values will be stored in your .MDB database file. Note that the elements may be in any order although they have been sorted to facilitate editing.

The format of the EMPMAC.DAT file is shown below :

  "b"     "ka"    "b"        3471         "Pouchou (1992)"

  "b"     "ka"    "c"        6750         "Pouchou (1992)"

  "b"     "ka"    "n"        11000        "Pouchou (1992)"

  "b"     "ka"    "o"        16500        "Pouchou (1992)"

  "b"     "ka"    "al"       64000        "Pouchou (1992)"

  "b"     "ka"    "si"       80000        "Pouchou (1992)"

  "b"     "ka"    "ti"       15000        "Pouchou (1992)"

  "b"     "ka"    "v"        18000        "Pouchou (1992)"

  "b"     "ka"    "cr"       20700        "Pouchou (1992)"

  "b"     "ka"    "fe"       27800        "Pouchou (1992)"

  "b"     "ka"    "co"       32000        "Pouchou (1992)"

  "b"     "ka"    "ni"       37000        "Pouchou (1992)"

  "b"     "ka"    "zr"       4400         "Pouchou (1992)"

  "b"     "ka"    "nb"       4500         "Pouchou (1992)"

  "b"     "ka"    "mo"       4600         "Pouchou (1992)"

  "b"     "ka"    "la"       2500         "Pouchou (1992)"

  "b"     "ka"    "ta"       23000        "Pouchou (1992)"

  "b"     "ka"    "w"        21000        "Pouchou (1992)"

  "b"     "ka"    "u"        7400         "Pouchou (1992)"

  "c"     "ka"    "b"        39000        "Pouchou (1992)"

  "c"     "ka"    "c"        2170         "Pouchou (1992)"

  "c"     "ka"    "si"       35000        "Pouchou (1992)"

  "c"     "ka"    "ti"       8097         "Pouchou (1992)"

  "c"     "ka"    "v "       8850         "Pouchou (1992)"

  "c"     "ka"    "cr"       10700        "Pouchou (1992)"

  "c"     "ka"    "fe"       13150        "Pouchou (1992)"

  "c"     "ka"    "zr"       25000        "Pouchou (1992)"

  "c"     "ka"    "nb"       24000        "Pouchou (1992)"

  "c"     "ka"    "mo"       20500        "Pouchou (1992)"

  "c"     "ka"    "hf"       18000        "Pouchou (1992)"

  "c"     "ka"    "ta"       17000        "Pouchou (1992)"

  "c"     "ka"    "w"        18000        "Pouchou (1992)"

  "n"     "ka"    "b"        15800        "Pouchou (1992)"

  "n"     "ka"    "n"        1640         "Pouchou (1992)"

  "n"     "ka"    "al"       13800        "Pouchou (1992)"

  "n"     "ka"    "si"       17000        "Pouchou (1992)"

  "n"     "ka"    "ti"       4270         "Pouchou (1992)"

  "n"     "ka"    "v "       4950         "Pouchou (1992)"

  "n"     "ka"    "cr"       5650         "Pouchou (1992)"

  "n"     "ka"    "fe"       7190         "Pouchou (1992)"

  "n"     "ka"    "zr"       24000        "Pouchou (1992)"

  "n"     "ka"    "nb"       25000        "Pouchou (1992)"

  "n"     "ka"    "mo"       25800        "Pouchou (1992)"

  "n"     "ka"    "hf"       14000        "Pouchou (1992)"

  "n"     "ka"    "ta"       15500        "Pouchou (1992)"

  "o"     "ka"    "li"       1600         "Bastin  (1992)"

  "o"     "ka"    "b"        8550         "Bastin  (1992)"

  "o"     "ka"    "b"        1200         "Bastin  (1992)"

  "o"     "ka"    "f"        1850         "Love et al. (1974)"

  "o"     "ka"    "ne"       2750         "Love et al. (1974)"

  "o"     "ka"    "na"       3630         "Love et al. (1974)"

  "o"     "ka"    "mg"       5170         "Bastin  (1992)"

  "o"     "ka"    "al"       6720         "Bastin  (1992)"

  "o"     "ka"    "si"       8790         "Bastin  (1992)"

  "o"     "ka"    "p"        9820         "Love et al. (1974)"

  "o"     "ka"    "s"        12400        "Love et al. (1974)"

  "o"     "ka"    "cl"       14300        "Love et al. (1974)"

  "o"     "ka"    "ar"       16100        "Love et al. (1974)"

  "o"     "ka"    "k"        20500        "Love et al. (1974)"

  "o"     "ka"    "ca"       24600        "Love et al. (1974)"

  "o"     "ka"    "sc"       26800        "Love et al. (1974)"

  "o"     "ka"    "ti"       19900        "Bastin  (1992)"

  "o"     "ka"    "cr"       2900         "Bastin  (1992)"

  "o"     "ka"    "mn"       3470         "Bastin  (1992)"

  "o"     "ka"    "fe"       4000         "Bastin  (1992)"

  "o"     "ka"    "co"       4500         "Bastin  (1992)"

  "o"     "ka"    "ni"       5120         "Bastin  (1992)"

  "o"     "ka"    "cu"       5920         "Bastin  (1992)"

  "o"     "ka"    "zn"       6350         "Bastin  (1992)"

  "o"     "ka"    "ga"       7090         "Bastin  (1992)"

  "o"     "ka"    "y"        15100        "Bastin  (1992)"

  "o"     "ka"    "zr"       16200        "Bastin  (1992)"

  "o"     "ka"    "nb"       17100        "Bastin  (1992)"

  "o"     "ka"    "mo"       18000        "Bastin  (1992)"

  "o"     "ka"    "ru"       19700        "Bastin  (1992)"

  "o"     "ka"    "sn"       15050        "Bastin  (1992)"

  "o"     "ka"    "ba"       4560         "Bastin  (1992)"

  "o"     "ka"    "la"       3600         "Bastin  (1992)"

  "o"     "ka"    "ta"       10600        "Bastin  (1992)"

  "o"     "ka"    "w "       11300        "Bastin  (1992)"

  "o"     "ka"    "pb"       11000        "Bastin  (1992)"

  "o"     "ka"    "bi"       12100        "Bastin  (1992)"

  "f"     "ka"    "xe"       27300        "Henke et al. (1982)"

  "na"    "ka"    "zn"       10500        "Henke et al. (1982)"

  "na"    "ka"    "pm"       7920         "Henke et al. (1982)"

  "mg"    "ka"    "tb"       8240         "Henke et al. (1982)"

  "al"    "ka"    "tm"       4730         "Henke et al. (1982)"

  "cr"    "la"    "te"       39500        "Henke et al. (1982)"

  "co"    "la"    "co"       1920         "Henke et al. (1982)"

  "ge"    "ka"    "ta"       265          "Henke et al. (1982)"

  "ge"    "la"    "gd"       8500         "Henke et al. (1982)"

  "mo"    "la"    "hg"       951          "Henke et al. (1982)"

 

The first column ("b" in the example equals Boron) is the atomic symbol of the emitting element. The second column ("ka" in the example equals Kα) is the x-ray line of the emitting element. The third column is the atomic symbol of the absorber element. The element and x-ray symbols must be enclosed in double quotes. The fourth column is the actual mass absorption coefficient (MAC) that has been experimentally measured. The last parameter is a comment string that may contain a comment, usually the experimenter or attribution. The comment string must be in double quotes.

The first and third columns (emitting atomic number and absorber atomic number) must be integer values from 1 to 100. The second column (x-ray line type) must be a valid x-ray line (ka, kb, la, lb, ma, or mb). The fourth column (MAC value) must be a real (or integer) number greater than zero.

See Appendix C below for a large set of empirical mass absorption coefficients from a number of sources that indicates some of the variation among MACs from various sources.