Author Topic: DTSAII Simulation - Low energy issues with the EDAX Octane detector  (Read 129 times)

Alessandro Lavacchi

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I am an enthusiastic user of DTSA2 that has completely changed my vision and practice of EDX spectroscopy.

These days, I am struggling with a simulation problem. DTSA2 simulations can’t reproduce the intensity of the peaks at energy lower than 1.5 keV in spectra acquired with an EDAX octane system equipped with a C2 Si3N4 window. Particularly, the intensity of the modeled peaks at low energy is much lower than the experimental ones; the lower the energy, the larger the discrepancy.

I have tried to eliminate the window doing multiple changes in the detector configuration. Whatever I do, I cannot get close to the experimental data. As I am dealing with bulk materials, both the analytical and Montecarlo models lead to the same result. Moreover, with my old SUTW Si(Li) detector, the agreement between simulations and experiments is great.

I am wondering if there is the possibility to define an arbitrary window that may solve the problem. My idea is to use the experimental data to define a list of transmission coefficients that I can introduce in my SDD configuration to drive the simulation to agree with the experimental data.

Do you think it’s reasonable?. If yes, do you have any suggestion on how to implement it (having a txt or a csv with the energy dependence of the transmission)?

Thank you!




NicholasRitchie

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I'm trying to figure a good way to do this...
There are calculated windows and combined tabulated/calculated windows.  The tabulated portions are added from a CSV file.  Maybe if the user adds a custom CSV file to the install directory, it could be used to define a custom window.

Windows may be only part of the problem as ionization cross sections and relaxation rates are poorly known for L & M lines.  Could just be bad physics in the model.

Nicholas

Alessandro Lavacchi

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Thank you, Nicholas.

The problem I have is mostly oxygen; quantitative modeling of oxides does not work with the Octane detector, while a get a reasonable agreement with the old SUTW Si(Li).

I'll proceed to try the window modification, calibrating the intensity against standards.

Best,

Alessandro