Hi Kurt
TOPAS models absorption edges well. Page 158 of the Technical Reference at http://www.topas-academic.net/Technical_Reference.pdf shows the result. The macro in question is modifies the emission profile which is how I think it should be modelled: macro Absorption_Edge_Correction_Eqn(& edge, & a_white, & b_white, & a_erf, & edge_extra) { modify_peak_eqn = ( Get(current_peak) + a_white Exp(- b_white (Get(current_peak_x) - edge)^2) / Tan(Th) ' Not necessary ' If(Get(current_peak_x) < edge, 1/Get(current_peak_x)^3, 1 ) ) (edge_extra + 0.5 (1 + Erf_Approx( a_erf (Get(current_peak_x) - edge))) ); } If someone spots a problem then I would be happy to know. The line commented out is due to the fact it makes little difference to the result. Cheers Alan From: rietveld_l-requ...@ill.fr <rietveld_l-requ...@ill.fr> On Behalf Of Kurt Leinenweber Sent: Monday, September 4, 2023 2:53 AM To: Thomas Gegan <tom.ge...@basf.com>; Bish, David L <b...@indiana.edu>; Shay Tirosh <stiro...@gmail.com>; Fernando Igoa <fer.igoa.1...@gmail.com> Cc: Rietveld List (rietveld_l@ill.fr) <rietveld_l@ill.fr> Subject: RE: [EXT] Re: [External] Re: Step-like basline Hi, Are these things modeled in Rietveld programs, by chance? It seems like a lot of baggage to put in a refinement but if it makes the results better. * Kurt From: rietveld_l-requ...@ill.fr <mailto:rietveld_l-requ...@ill.fr> <rietveld_l-requ...@ill.fr <mailto:rietveld_l-requ...@ill.fr> > On Behalf Of Thomas Gegan Sent: Sunday, September 3, 2023 9:16 AM To: Bish, David L <b...@indiana.edu <mailto:b...@indiana.edu> >; Shay Tirosh <stiro...@gmail.com <mailto:stiro...@gmail.com> >; Fernando Igoa <fer.igoa.1...@gmail.com <mailto:fer.igoa.1...@gmail.com> > Cc: Rietveld List (rietveld_l@ill.fr <mailto:rietveld_l@ill.fr> ) <rietveld_l@ill.fr <mailto:rietveld_l@ill.fr> > Subject: RE: [EXT] Re: [External] Re: Step-like basline I agree with a Ni absorption edge, possibly with a Kβ peak around 38° 2θ. Tom Gegan Chemist III Phone: +1 732 205-5111, Email: <mailto:tom.ge...@basf.com> tom.ge...@basf.com Postal Address: BASF Corporation, , 25 Middlesex Essex Turnpike, 08830 Iselin, United States From: rietveld_l-requ...@ill.fr <mailto:rietveld_l-requ...@ill.fr> <rietveld_l-requ...@ill.fr <mailto:rietveld_l-requ...@ill.fr> > On Behalf Of Bish, David L Sent: Sunday, September 3, 2023 7:08 AM To: Shay Tirosh <stiro...@gmail.com <mailto:stiro...@gmail.com> >; Fernando Igoa <fer.igoa.1...@gmail.com <mailto:fer.igoa.1...@gmail.com> > Cc: Rietveld List (rietveld_l@ill.fr <mailto:rietveld_l@ill.fr> ) <rietveld_l@ill.fr <mailto:rietveld_l@ill.fr> > Subject: [EXT] Re: [External] Re: Step-like basline Some people who received this message don't often get email from b...@indiana.edu <mailto:b...@indiana.edu> . Learn why this is important <https://urldefense.com/v3/__https:/aka.ms/LearnAboutSenderIdentification__; !!IKRxdwAv5BmarQ!fFhSHn4S5iEzkW-O9lvWG-OzoqK_2SKhRniGa71nxuOL3GcxiyD83i2mnNN 0Z48HPkn4zjKqH-aqqA$> Hello Shay, I think it is probably related to "tube tails". You can read about this in the literature (e.g., on the BGMN web site) and you can model it in some Rietveld software such as Topas. You don't normally notice this but it becomes apparent with higher-intensity peaks. Regards, Dave _____ From: rietveld_l-requ...@ill.fr <mailto:rietveld_l-requ...@ill.fr> <rietveld_l-requ...@ill.fr <mailto:rietveld_l-requ...@ill.fr> > on behalf of Fernando Igoa <fer.igoa.1...@gmail.com <mailto:fer.igoa.1...@gmail.com> > Sent: Sunday, September 3, 2023 3:06 AM To: Shay Tirosh <stiro...@gmail.com <mailto:stiro...@gmail.com> > Cc: Rietveld List (rietveld_l@ill.fr <mailto:rietveld_l@ill.fr> ) <rietveld_l@ill.fr <mailto:rietveld_l@ill.fr> > Subject: [External] Re: Step-like basline This message was sent from a non-IU address. Please exercise caution when clicking links or opening attachments from external sources. Hey Shay, Are you using a motorized slit during the measurement? These may open up abruptly to compensate for the angular dependence of the footprint and thus generate an abrupt increase in the intensity. Hope it helps :) On Sun, Sep 3, 2023, 8:50 AM Shay Tirosh <stiro...@gmail.com <mailto:stiro...@gmail.com> > wrote: Dear Rietvelders I am attaching a zoom-in on a diffraction profile. My question is what is the origin of the step-like profile next to a very large reflection peak? Is it a sample preparation problem? Is it part of the baseline? Thanks Shay -- ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com <mailto:alan.he...@neutronoptics.com> > Send commands to <lists...@ill.fr <mailto:lists...@ill.fr> > eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ <https://urldefense.com/v3/__http:/www.mail-archive.com/rietveld_l@ill.fr/__ ;!!IKRxdwAv5BmarQ!fFhSHn4S5iEzkW-O9lvWG-OzoqK_2SKhRniGa71nxuOL3GcxiyD83i2mnN N0Z48HPkn4zjJTf8rNHg$> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Please do NOT attach files to the whole list <alan.he...@neutronoptics.com> Send commands to <lists...@ill.fr> eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
