LibCPIXE Frequently Asked Questions (FAQ)

FAQ index

1. What is LibCPIXE? [go]
   
2. What is CPIXE? [go]
   
3. Why another PIXE analysis code [go]
   
4. What does LibCPIXE calculate? [go]
   
5. What is still pending in LibCPIXE? [go]
   
6. What DataBases does LibCPIXE use? [go]
   
7. What is the intended audience of LibCPIXE and CPIXE? [go]
   
8. Has LibCPIXE already been tested in some program? [go]
   
9. Can I use LibCPIXE for implementing PIXE support in my own program? [go]
   
10. How much does it cost? [go]
    
11. Isn't DataFurnace violating the GPL license of LibCPIXE? [go]
    

1. What is LibCPIXE? [index]

   LibCPIXE is a computer library for PIXE data analysis written in C. It is comprised by a set of routines to handle data and simulating X-Ray yields from an arbitrary sample under general experimental conditions. Its source code, originally based on the DATTPIXE program, is freely available.

2. What is CPIXE? [index]

   CPIXE is a simple program developed for testing and demonstrating the capabilities of the LibCPIXE library. It is distributed together with the library and runs under both GNU/Linux and MS Windows systems.

3. Why another PIXE analysis code [index]

   LibCPIXE is not like the other available codes. In fact, it is not a program but a library that can be used to implement PIXE support into other programs.
   We developed it because we wanted to have a fast and totally general PIXE simulator in order to be able of using Bayesian Inference techniques for sample characterization using PIXE data.

4. What does LibCPIXE calculate? [index]

   Emission intensities of K and L lines (and sub-shells ) with 1keV < Ex < 30keV can be calculated. M lines can be calculated but the code is still not tested for that.
   Secondary fluorescence correction in multilayered samples is in testing phase.
   Arbitrary sample & filter definition: no limitations in the number of layers or in the elements present in each layer.

5. What is still pending in LibCPIXE? [index]

   Databases for ions other than protons have not been incorporated yet.
   Currently, the spectra are not reconstructed. Only the intensities of the characteristic emissions are simulated (e.g. no background and no detector resolution are calculated). In order to use LibCPIXE for fitting, the experimental spectra must be processed to extract the areas of the relevant peaks.

6. What DataBases does LibCPIXE use? [index]

   X-ray cross sections (semiempirical corrections to ECPSSR theory):
   
   For K lines: H. Paul, Nucl. Instr. and Meth in Phys. Res. B3 (1984) 5-10
   For L lines: M.A.Reis, A.P.Jesus, At. Data and Nucl. Data Tables, 63 (1996) 1-55
   
   Fluorescence yields (Coster-Kronig): M.O. Krause, J. Phys. Chem Ref. Data , 8 (1979) 307-327
   Line transition ratios (K & L):
   
   J. Scofield, Phys. Rev. A, 9 (1974)
   J. Scofield,, At. Data and Nuclear Data Tables 14(1974) 121-137
   
   Ion stopping: J.F. Ziegler, J.P. Biersack, U.Littmark, “Stopping and Ranges of ions in Solids”, Pergamon, 1985.
   X-ray absorption coefficients: E.F. Plechaty, D.E. Cullen, R.J. Howeton, Report DLC-7, Lawrence Radiation Laboratory (1975).

7. What is the intended audience of LibCPIXE and CPIXE? [index]

   Anyone can use CPIXE for a quick simulation or analysis of a sample, but the intended audience of LibCPIXE is IBA software developers who want to implement support for PIXE into their codes.

8. Has LibCPIXE already been tested in some program? [index]

   Apart from CPIXE, the library has already been incorporated into the DataFurnace code allowing us to perform Bayesian Inference analysis of PIXE data, including differential PIXE and simultaneous PIXE+RBS fits (see examples).

9. Can I use LibCPIXE for implementing PIXE support in my own program? [index]

   Yes, the LibCPIXE library is written to be simple to use and to incorporate into other programs. It is programed in C but linking to programs written in other languages should not be a problem. In fact, a Fortran90 interface layer is already available. A lot of care was taken to use platform-independent code.

10. How much does it cost? [index]

    Nothing. both LibCPIXE and CPIXE are free. The source code is distributed under the General Public License (GPL). If this license does not fit your needs (e.g. you want to incorporate it into non-free software), please contact the authors.
    Note: please do not mistake LibCPIXE or CPIXE with DataFurnace. The former are free (GPL) while the later is a proprietary program (Which ships LibCPIXE under a special license).

11. Isn't DataFurnace violating the GPL license of LibCPIXE? [index]

    No. DataFurnace ships a separate version of LibCPIXE that we, the authors, have licensed under terms different to those of the GPL. This version is virtually identical to the GPLed one and changes are very likely to be kept in sync. In other words, DataFurnace pays for the right to ship LibCPIXE without having to release its source code.