Many of your questions are addressed in the documentation for Athena: http://cars9.uchicago.edu/%7Eravel/software/doc/Athena/html/ --Scott Calvin Sarah Lawrence College On Jan 2, 2013, at 7:14 PM, Zhaomo Tian wrote: Dear all, I feel confused about the backgound subtraction process in Athena, I think the backgound subtraction is actually a complicated process containing some algorithms , but it seems the Athena program just let us do backgound subtraction by applying some easy work such as energy calibration and by changing some values of parameters such as pre-edge range or spline range...Is that true? And I ususally just use the default values of parameters in the left panel in Athena,are those parameter with different values mattering a lot to the quality of backgound subtraction? I do not know how to change parameter values in order to get a better backgound subtraction.How can I compare between different backgound subtractions? ? Thanks so much! Tian Zhaomo M.S. candidate Lab. For Photosynthesis Materials and Devices Department of Materials Science and Engineeing,POSTECH san 31, Hyoja-Dong, Nam-Gu, Pohang, 790-784, Republic of Korea office: +82-54-279-2827 mobile: +82-10-7747-3790 e-mail: zhaomo1989@postech.ac.krmailto:zhaomo1989@postech.ac.kr _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.govmailto:Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit