This page (revision-12) was last changed on 07-Dec-2016 14:14 by David R Williams

This page was created on 09-Jul-2007 12:35 by JianSun

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Page revision history

Version Date Modified Size Author Changes ... Change note
12 07-Dec-2016 14:14 2 KB David R Williams to previous Took out the discussion about FWHM versus natural width because it was confusing. Result now summarised.
11 22-Jan-2009 05:36 4 KB David R Williams to previous | to last Reply to comment by Celine Boutry, and correction to the description of the instrumental width.
10 21-Jan-2009 15:12 3 KB CelineBoutry to previous | to last
9 21-Jan-2009 09:00 2 KB David R Williams to previous | to last
8 21-Jan-2009 09:00 2 KB David R Williams to previous | to last
7 21-Jan-2009 08:59 2 KB David R Williams to previous | to last
6 21-Jan-2009 08:58 2 KB David R Williams to previous | to last Response to Celine Boutry's question about the instrumental width.
5 21-Jan-2009 08:47 2 KB David R Williams to previous | to last
4 16-Jan-2009 15:36 1 KB CelineBoutry to previous | to last instrumental width
3 09-Jul-2007 13:00 955 bytes Louise Harra to previous | to last
2 09-Jul-2007 12:36 1 KB JianSun to previous | to last
1 09-Jul-2007 12:35 1 KB JianSun to last

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InstrumentalWidthOfEIS...nobody
InstrumentalWidthOfEIS

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At line 37 changed one line
__NOTE!__ However, the instrumental width that is discussed by Brown ''et al.'' is __not__ the FWHM of the instrumental width, but rather the (1/e)%%sup -1/2%% half-width σ that naturally falls out of the Gaussian function:
%%strike __NOTE!__ However, the instrumental width that is discussed by Brown ''et al.'' is __not__ the FWHM of the instrumental width, but rather the (1/e)%%sup -1/2%% half-width σ that naturally falls out of the Gaussian function: %%
At line 39 changed one line
G(x) = exp ( -x%%sup 2%% / 2 (σ%%sup 2%%) )
__NOTE!__ As Céline Boutry points out, this is the FWHM of the instrumental width, not the Gaussian width σ as previously incorrectly stated here.
At line 41 removed 13 lines
The Gaussian width σ is related to the FWHM by the relation:
FWHM = 2 × (2 ln(2) )%%sup 1/2%% × σ
''i.e.,''
FWHM = 2.356 σ
I hope this helps. And please let me know if I've slipped up in my maths!
--[Dave Williams|DavidRWilliams], 21-Jan-2009
At line 62 added 10 lines
Hi, Céline.
Vous avez raison! :-)
I looked at my original notes, and you're quite right: the σ-to-FWHM factor is included.
I've amended the above to show this now. Thanks.
--[Dave Williams|DavidRWilliams], 22-Jan-2009
This page (revision-12) was last changed on 07-Dec-2016 14:14 by David R WilliamsTop