µFinder
B: The Mass Attenuation Coefficients
Embedded Files
Querying the NIST XCOM Database
Querying the NIST XCOM Database
By clicking the Calculate button, this program will query simultaneously all the listed matrices having a red square at its left.
The user can Cancel at anytime all the processes at once.
When the program is busy calculating/querying a given matrix, the respective row will display a yellow square.
When a matrix has been fully calculated it will display a green square.
The next time a batch calculation starts, the matrices having green squares will be skipped from the calculations.
Batch Calculations
Batch Calculations
You can select (or list) a given matrix for calculations by double-clicking the green/red square. It will change color.
Only matrices having red squares will be considered during the calculation process.
In the following 2 examples, when the button Calculate is pressed:
only the Ba Oxide matrix will be calculated (left);
seven matrices will be calculated simultaneously (right).
Accumulating new results
Accumulating new results
By default the program searches for mass attenuation coefficients between 1 - 4000 keV. You can change the query parameters by clicking the Setup button. To accumulate results from new (energy) queries, activate the option Accumulate Results (it is activated by default). Otherwise the program will keep the results from the latest query.
See further in the Preferences section of this Tutorial.
The Plots
The Plots
When a matrix has been calculated, the plots and data will be available at the right-side panel.
These plots are divided according to energy ranges and are listed on the left side. For instance, for the matrix Ba Oxide one has:
a Full plot for the 1 keV to 100 GeV energy range,
a plot for the 1 - 4001 keV energy range,
a Last plot to remind you of your last queried energy range. The energy range can be specified with the Setup button at the Menu bar.
Exporting the Data
Exporting the Data
It is possible to export a .csv or .xls file version of the data by double-clicking the Comma Separated or Spreadsheet labels in the list.
It is also possible to save, print and email the information by right-clicking its content window and selecting the corresponding function.
The Units
The Units
The mass attenuation coefficient unit employed is the cm2/g. This physical quantity can be multiplied by the matrix density (in g/cm3) to yield the linear attenuation coefficient (in 1/cm).
The Coefficients Table
The Coefficients Table
Under the tab Coefficients a table is shown with the mass attenuation coefficients values for the different interaction mechanisms:
Coherent and Incoherent Scattering, Photo Electric effect, Pair Production under a neutron field, Pair Production under an electron field. There is also a column for the Total mass attenuation from all contributions.
The last column corresponds to the Total mass attenuation from all contributions except for Coherent Scattering.
This table follows the same format given by the program NIST XCOM.
You can select this table and copy it (CTRL + C ) to Microsoft Excel or to another spreadsheet software, but you can also export the data as .xls and .csv files following the procedure mentioned in the previous section.
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