FFAST MACs

[Philipp Poeml]

Hi,

who has compiled the ffast.dat and ffast2.dat? And how was it done?
There are some gaps, for example Y Lg or Gd Ln, why?
Why do the tables stop at U?

Thanks!

[Probeman]

Hi Philipp,
Phil Gopon made these tables up when he was at Wisconsin.  You'd have to ask him I guess. I think he's still at Oxford.

Some of the tables he sent me have emissions lines up to Am, so I'll need to look and see why you say they stop at U.

This reminds me that you mentioned you were going to create some additional MAC tables for us using Penepma scattering databases?  Is that still on your radar?
john

[Philipp Poeml]

Hi John,

ok, I could ask him. Thanks.
The MAC tables I have in Calczaf all stop at U. It would be nice to calculate them up to Cm.
Emmission lines, yes, there are some up to Am, which is still not enough. :-)

Cheers
Philipp

[John Donovan]

Hi John,

ok, I could ask him. Thanks.
The MAC tables I have in Calczaf all stop at U. It would be nice to calculate them up to Cm.
Emmission lines, yes, there are some up to Am, which is still not enough. :-)

Cheers
Philipp

After glancing at the code I see what's going on.  The FFAST MACs for Ka, Kb, La, Lb, Ma, Mb came from Nicholas Ritchie at NIST, the FFAST MACS for Ln, Lg, Lv, Ll, Mg, Mz came from Phil Gopon. Nicholas only sent MACs for elements up to U, Phil's data included lines up to Am.

Here's a deal: I'll send you the tables by email, and if you edit them to include new FFAST values from Chantler I will incorporate those into the CalcZAF tables.

[Philipp Poeml]

Strange. For the FFAST MACS for Ln, Lg, Lv, Ll, Mg, Mz they do not contain values above U in my Calczaf. It seems to be the latest version of the file.

Thanks for sending the files. I can edit them, but will have to see how to obtain new values.

[Probeman]

Strange. For the FFAST MACS for Ln, Lg, Lv, Ll, Mg, Mz they do not contain values above U in my Calczaf. It seems to be the latest version of the file.

Thanks for sending the files. I can edit them, but will have to see how to obtain new values.

Hi Philipp,
OK, I see where I got confused. The FFAST tables from Ritchie and Gopon only include absorbers up to U (and this may be a limitation of the original Chantler tabulation), but the FFAST2.DAT table of the Ln, Lg, Lv, Ll, Mg, Mz emission lines do include emitters higher than U. Here are the MACs for x-rays lines of Am from FFAST2.DAT:

Code Select Expand

"Table of MACs (mass absorption coefficients) from C:\ProgramData\Probe Software\Probe for EPMA\FFAST2.DAT"
"Emitting Element: Am"
Absorber       Ln       Lg       Lv       Ll       Mg       Mz
      H                                                
      He                                                
      Li      .02      .01      .01      .06     2.81     9.16
      Be      .07      .03      .03      .19     8.43    26.88
      B      .17      .07      .07      .46    19.45    59.53
      C      .36      .15      .14      .98    38.71   116.26
      N      .64      .26      .25     1.70    63.43   189.16
      O     1.03      .43      .41     2.71    95.84   282.83
      F     1.47      .62      .59     3.86   129.76   377.57
      Ne     2.22      .94      .89     5.71   188.13   531.07
      Na     2.93     1.26     1.20     7.49   240.18   667.73
      Mg     4.01     1.73     1.65    10.21   314.72   869.24
      Al     5.10     2.21     2.12    12.90   381.68 1035.70
      Si     6.70     2.93     2.80    16.83   485.96 1287.31
      P     8.13     3.57     3.42    20.30   565.69 1481.27
      S    10.31     4.54     4.35    25.68   683.04 1773.14
      Cl    12.02     5.30     5.08    29.81   763.33   186.30
      Ar    13.52     5.98     5.73    33.12   825.46   213.30
      K    17.25     7.65     7.33    41.62 1007.01   276.64
      Ca    20.64     9.22     8.83    49.27   121.85   337.05
      Sc    22.16    10.03     9.61    52.74   133.38   370.39
      Ti    24.85    11.36    10.89    59.18   151.90   422.28
      V    27.68    12.69    12.18    65.97   171.66   477.14
      Cr    31.94    14.63    14.04    76.08   200.59   556.37
      Mn    35.40    16.23    15.58    83.54   224.67   618.99
      Fe    40.51    18.61    17.87    94.28   260.69   709.85
      Co    44.33    20.42    19.60   101.99   290.02   778.70
      Ni    50.97    23.59    22.64   116.35   339.66   904.56
      Cu    53.45    24.89    23.91   121.98   363.31   961.49
      Zn    58.62    27.49    26.40   132.86   403.53 1070.94
      Ga    61.78    29.13    27.98   138.18   429.48 1141.81
      Ge    66.40    31.45    30.22   147.35   466.60 1240.66
      As    71.63    34.05    32.73   159.99   509.11 1352.19
      Se    75.34    35.96    34.57    21.63   543.34 1431.85
      Br    81.79    39.41    37.89    24.11   603.39 1575.96
      Kr    85.53    41.59    40.00    25.87   648.35 1675.09
      Rb    91.98    44.92    43.21    28.42   709.01 1817.64
      Sr    99.33    48.20    46.38    31.62   776.85 1976.18
      Y    14.70    51.91    49.99    34.92   843.54 2139.50
      Zr    16.01    55.06    53.05    38.07   902.49 2279.85
      Nb    17.51    58.77    56.61    41.69   972.90 2288.89
      Mo    18.84    61.76    59.47    44.84 1030.82 2275.13
      Tc    20.43    65.75    63.23    48.50 1101.34 1096.01
      Ru    21.89    10.17    66.62    51.75 1156.21   504.70
      Rh    23.71    11.00    10.57    55.69 1244.18   549.37
      Pd    25.22    11.69    11.23    58.82 1323.16   587.78
      Ag    27.31    12.64    12.15    63.22 1403.84   638.51
      Cd    28.63    13.28    12.76    65.98 1251.91   674.04
      In    30.51    14.20    13.64    70.07   960.74   723.03
      Sn    32.01    14.98    14.38    73.36   292.83   762.09
      Sb    33.76    15.89    15.26    77.35   313.15   809.34
      Te    34.75    16.47    15.82    79.73   327.56   841.78
      I    37.69    17.92    17.22    86.60   360.35   921.04
      Xe    39.26    18.70    17.98    90.44   380.40   968.02
      Cs    41.86    19.97    19.20    96.65   411.92 1039.75
      Ba    43.52    20.76    19.97   100.70   431.67 1086.56
      La    46.22    22.02    21.18   107.03   461.35 1155.84
      Ce    49.22    23.42    22.53   113.84   494.39 1236.48
      Pr    52.50    24.97    24.02   121.05   528.77 1317.84
      Nd    54.94    26.13    25.14   126.16   553.15 1376.33
      Pm    58.50    27.84    26.78   133.62   585.58 1463.38
      Sm    60.33    28.72    27.63   136.99   602.30 1505.63
      Eu    63.75    30.35    29.20   143.98   634.42 1584.70
      Gd    65.63    31.28    30.09   147.57   652.17 1625.91
      Tb    69.16    33.00    31.75   155.06   688.90 1715.52
      Dy    71.80    34.35    33.05   160.71   714.90 1775.56
      Ho    75.08    35.99    34.62   167.90   747.60 1848.49
      Er    78.44    37.70    36.27   175.07   781.69 1924.77
      Tm    82.15    39.60    38.10   182.99   819.60 2009.57
      Yb    84.82    40.98    39.43   188.73   847.21 2066.21
      Lu    88.58    42.90    41.28   196.17   884.06 2144.38
      Hf    91.71    44.49    42.82   202.37   918.11 2218.59
      Ta    95.34    46.36    44.63   210.37   957.67 2254.17
      W    98.94    48.15    46.36   217.17   996.43 2291.12
      Re   102.68    50.11    48.25   195.47 1038.57 2312.21
      Os   105.77    51.67    49.75   150.04 1070.29 2312.78
      Ir   110.05    53.80    51.81   150.76 1112.27 2417.42
      Pt   113.90    55.77    53.71   156.64 1150.03 2516.83
      Au   118.43    58.05    55.91   163.39 1193.49 2250.98
      Hg   121.98    59.88    57.68   169.06 1226.72 2341.51
      Tl   125.55    61.69    59.42    66.39 1262.48 2437.93
      Pb   129.59    63.82    61.48    68.98 1302.84 2547.06
      Bi   134.34    66.32    63.88    71.96 1297.23 2235.56
      Po   121.46    69.49    66.94    75.69 1370.79 1295.72
      At    93.06    72.39    69.75    79.09 1340.25   726.67
      Rn    89.21    71.59    68.99    78.51 1335.17   728.79
      Fr    93.05    74.48    71.77    81.86 1395.65   766.40
      Ra    95.98    76.69    73.90    84.45 1440.77   803.80
      Ac    99.81    79.64    76.76    87.93 1295.23   836.03
      Th   101.82    81.18    78.26    89.93 1332.23   862.16
      Pa    75.05    84.88    81.85    94.25 1433.41   904.45
      U    43.53    85.64    82.62    95.40 1429.03   916.72
      Np                                                
      Pu                                                
      Am                                                
      Cm                                                
      Bk                                                
      Cf                                                
      Es                                                
      Fm                                                


So we'll have to wait to hear from you or Nicholas as to whether we can proceed with absorbers higher than U for the Chantler tabulation.

[Philipp Poeml]

Yes, this is correct. The file has emission lines up to Am, but not absorbers. I find it strange. Why stop there? Why not do up to Am for absorbers? Or better Cm?
If I knew how ffast works I could complete the job...

[John Donovan]

Yes, this is correct. The file has emission lines up to Am, but not absorbers. I find it strange. Why stop there? Why not do up to Am for absorbers? Or better Cm?
If I knew how ffast works I could complete the job...

I do not know. You'll have to ask Nicholas Ritchie.  You can also check the NIST web site and see if they have absorbers past U.  I thought you and Karen and Mike had curated your own MAC table for the actinides?
john

[Philipp Poeml]

Hi John,

I think Mike does not bother so much about Am and Cm in his place...

The irradiated fuel labs use a strange database. It is a mix of the Pouchou and Pichoir MACs, which are Henke 82 MACs with some modifications and then for Am, Cm and other lines the database contains Farthing and Walker MACs, who use Heinrich's equations and slightly modified them and extrapolated them for elements 93-96...

We'll sort that out with Xavier in a nice paper soon...

[Nicholas Ritchie]

The FFAST MACs come from here - https://www.nist.gov/pml/x-ray-form-factor-attenuation-and-scattering-tables.  They are tabulations of form factors, mass attenuation coefficients, mass absorption coefficients, etc for all energies from << 1 keV to 433 keV for the elements H to U.  They are computed using a self-consistent Dirac-Hartree-Fock framework.   I like them because the tabulations can be interpolated to give MACs for not only characteristic lines but also continuum (and any other X-ray source.)  However, they are tabulations and must be interpolated.    I do this in DTSA-II and when John asked for MACs for certain lines, I wrote a script to extract the MACs for each element at the energy of each characteristic line of interest.  (For those of you interested in the computer language Julia, there is an implementation of the FFAST MACs in Julia available here https://github.com/usnistgov/FFAST.jl.  It is a work-in-progress but it seems to work ok.)

When John asked about extending FFAST above U, I checked for more recent references and wrote to the author of the FFAST database - Chantler.  I haven't heard back but I suspect that elements above U won't be forthcoming.

Nicholas

[Philipp Poeml]

Hi Nicholas,

thanks for the explanations. I checked your FFAST implementationon github, but did not try it yet.

I guess what I did not yet understand is:
These MACs are computed by some algorithms, right? Is that extremely complicated? Can't I take these algorithms and do the calculations for Am, Cm? Or is there some input data missing for these elements? Like, some factors or cross sections or whatever are not known?

Cheers
Philipp