To: Dan Dewey <dd>
Cc: lpd@head-cfa.harvard.edu, belinda@head-cfa.harvard.edu
Subject: Re: HRMA areas 
In-Reply-To: Your message of "Tue, 21 Oct 1997 12:25:44 EDT."
	<199710211625.MAA19112@spectra.mit.edu> 
Date: Tue, 21 Oct 1997 12:43:10 -0400
From: Ping Zhao <zhao@head-cfa.harvard.edu>
Status: R
Content-Length: 2249


Hi, Dan:

Yes, I produced the following file.  It is the current best raytracing
results for the 2pi effective area.  It does include the 12 supporting
struts obstruction and CAP and all the pre- and post- collimators and
apertures.  NO MORE vigneeting factors need to apply.

We are still trying to close the gap between the model and the data. 
THere are still a few percent difference.  So these numbers may change
accordingly.  But Fred said this is good enough for the observer's
guide.

Thanks,

Ping


> Ping, Larry, 
> 
>   I believe you created a file which begins with:
> 
>   0.01000    386.5537    255.2093    199.7004    106.9064    948.3429
>   0.01016    386.5434    255.2037    199.6965    106.9047    948.3214
>   0.01033    386.5332    255.1982    199.6926    106.9031    948.3002
>   0.01049    386.5233    255.1928    199.6888    106.9015    948.2795
>  and ends with
>  29.05260      0.0000      0.0000      0.0000      0.0002      0.0003
>  29.52250      0.0000      0.0000      0.0000      0.0002      0.0002
>  30.00000      0.0000      0.0000      0.0000      0.0002      0.0002
>  and has in the middle
>   0.98378    308.9288    213.5945    170.7672     95.1800    788.4705
>   0.99970    308.9532    213.6302    170.7907     95.1923    788.5663
>   1.01586    308.9893    213.6721    170.8192     95.2067    788.6871
>   1.03229    309.1009    213.7553    170.8776     95.2334    788.9670
> 
> 
> This data file is as far as I know the first/only/best release of
> the HRMA areas on a fine energy grid from MST (using synchrtron above
> 2 keV for example).
> 
>   In the past Leon would produce effective areas and add that a
> vigneeting factor of order 0.9 should be applied to account for
> the CAP struts etc.  (Likewise if a geometrical mirror model
> is used the 0.9 or whtever must be included for thsi vignetting).
>   SO, a factor of 0.9 is being applied to this current file
> you have issued - SHOULD any factor be applied?
> 
>   As for the "35 mm" - I added that as a way of saying this
> is the effective area into 2pi?  What aperture is it the effective
> area for?
> 
>   THANKS - I'd like to get all these fine points ironed
> out before we load much of these data into the ASC archive,
> 
>    -Dan
>