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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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 52 added 23 lines
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Hi,
Thank you for your answer. I have to say that I'm puzzled about which kind of width is discussed in the papers.
About the Brown ''et al'' 2008 paper, they wrote : "The thermal Doppler FWHM is given by Δ%%sub D%%=7.162× 10e(-7)λ(T/M)%%sup 1/2%%". The 7.162× 10e(-7) coefficient is : 2 × (2 ln(2) )%%sup 1/2%% × *(k%%sub B%%/u) %%sup 1/2%%×c
where u is the Atomic Mass Unit in kg, k%%sub B%% is the Boltzmann constant and c is the Speed of light.
So Δ%%sub D%% is well a FWHM.
and then they wrote : "Δ=(Δ%%sub inst%%%%sup 2%%+Δ%%sub NT%%%%sup 2%%+Δ%%sub D%%%%sup 2%%)%%sup 1/2%%"
So Δ%%sub inst%% needs to be a FWHM to be homogeneous.
The value given just then is Δ%%sub inst%%=0.055=(0.056%%sup 2%%-0.009%%sup 2%%)%%sup 1/2%% which is consistent with the Doschek ''et al'' value if it is the FWHM but not if it is the gaussian σ.
\\
So, I don't understand your comment that this value in Brown ''et al'' is the gaussian σ and not the FWHM.
--[Celine Boutry], 21-Jan-2009
This page (revision-12) was last changed on 07-Dec-2016 14:14 by David R WilliamsTop