SEU Weibull-Fit App

Weibull Parameters

Enter values for LETth and Sigma to find best fit:



Cross Section Data



Or Upload Your Data:



Weibull Parameters

Enter values for Eth and Sigma to find best fit:





Cross Section Data



Or Upload Your Data:



Instructions

About

This app aims to assist the radiation effects engineer to analyze single-event upset (SEU) cross section data. The app automates the process of determining appropriate Weibull fit parameters. The app plots the cross section data with fit data. You can download a reformatted, high resolution image that's suitable for publication or presentation. The Weibull fit raw data is also available for download. Additionally, the app provides estimated on-orbit rates using methods described above.

To upload data, either enter the cross section data individually or upload a csv file. The csv file must contain columns of data in the following order, with column names in the 1st row.

  • Column 1: LET in units of (MeV⋅cm2/mg) or Energy in units of (MeV) for protons
  • Column 2: Cross section in units of (cm2)
  • Column 3: Fluence (optional)
  • Column 4: Count (optional)
  • Column 5, 6, ... n: Optional variable - e.g. voltage, load, frequency, temperature, etc.

Error bars

The program calculates error bars when the fluence and/or error count are available. Error bars are calculated for Poisson errors at upper 95% confidence interval.

Heavy ion FOM rate

Additionally, the App calculates the SEU figure-of-merit (FOM) and the respective on-orbit rate in GEO. The SEU FOM is determined using the technique described by Ed Petersen [1]. The GEO on-orbit event rate uses a scaling factor of 360x for unhardened technologies per the referenced paper. A scaling factor of 90x may be more appropriate for hardened technologies. The FOM represents quick estimate of the event rate. The user may also choose to use tools such as CREME96 to calculate an error rate using the Weibull parameters extracted by this App [2].

Proton upset rate calculation

The proton upset rate is calculated by assuming a step-function profile for the cross section. The program calculates the upset rate by multiplying the saturating cross section (from the Weibull parameters) by the integral flux at a given threshold energy. The integral flux is determined from the user-chosen mission parameters, which includes the orbit profile, shielding, solar condition, and solar particle (flare) condition. The threshold energy is either provided by the user data, or determined by the shielding thickness selected by the user.

[1] E. Petersen, "The SEU Figure of Merit and Proton Upset Rate Calculations," IEEE Trans. Nucl. Sci., vol. 45, no. 6, Dec. 1998, pp. 2550 - 2562.
[2] https://creme.isde.vanderbilt.edu/

Updates

March 12, 2021: Moved app to new server at apps-eeeradiation.com/see-analysis. Fixed bugs: Corrected 1) proton ISS Peak 5 min rates, 2) missing tick labels from downloaded plot.

November 11, 2020: New feature to find best fit has been implemented. Best fit is determined by calculating the nonlinear least-squares estimates of the Weibull fit parameters - i.e. shape and width. The location (LETth or Eth) and the weighting factor (sigma) are to be supplied by the user. Also fixed bugs related to plotting error bars and 0 count events.

October 13, 2019: We've recently expanded the capability to fit proton SEE data and calculate upset rates for select mission profiles.

September 7, 2019: The algorithm previously had not accepted data inputs with 0 error count, as may be needed to indicate an event threshold level. The latest update allows data entry with 0 error count. However, the corresponding fluence information must be present in order to calculate a valid upper bound error. For each LET where there was no error observed, enter 0 for the count, enter the fluence, and just leave the cross section entry empty.

Report bugs, send comments or questions to: admin@eeeradiation.com