Re: Fwd: solar-b diffraction

[Kano Ryouhei <ryouhei.kano@nao.ac.jp>]

Dear Deluca san and Golub san

Thank you for your information on the X-ray aperture.  I have not yet
fully understand the mask pattern which Golub san forwarded to me. But 
the value for the width is very useful for understanding the
fundermental pattern of the XRT diffraction.

I also check the luna limb and the solar limb. Now, I think that the
dimming on the solar limb in Al/mesh image is probably a actual
feature in the solar atomosphere.


Thank you and see you in Hawaii,
R.Kano

From: Ed Deluca <edeluca@cfa.harvard.edu>
Subject: Fwd: solar-b diffraction
Date: Wed, 23 May 2007 16:50:05 -0400
Message-ID: <0DD102F7-A664-456F-911A-E55BCA996178@cfa.harvard.edu>

> Hi Kano san,
> 
>   Below is an answer to your question about the width of the  
> aperture, 0.32mm.
> 
>   There is no additional masking by the filter frames or aperture stop.
> 
>   Paul Reid was at Danbury Optical when the XRT mirror was being
> designed and manufactured. He is now at SAO.
> 
> Ed
> 
> ===================================================================
>        Dr. Edward E. DeLuca           Smithsonian Astrophysical  
> Observatory
>        edeluca@cfa.harvard.edu     MS 58
> Office 617 496 7725                     60 Garden Street
> Fax     617 496 7577                     Cambridge, MA  02138
> Cell    508 728 5424                     USA
> ===================================================================
> 
> 
> Begin forwarded message:
> 
> > From: Paul Reid <preid@cfa.harvard.edu>
> > Date: May 23, 2007 1:08:59 PM EDT
> > To: Leon Golub <lgolub@cfa.harvard.edu>, "Peter Cheimets"  
> > <pcheimets@cfa.harvard.edu>, edeluca <edeluca@cfa.harvard.edu>
> > Cc: "Reid, Paul" <preid@cfa.harvard.edu>
> > Subject: solar-b diffraction
> >
> > Alright, so it's pretty close to linear...
> >
> > I get 0.32 mm aperture width for the as-built, and an original  
> > nominal as 0.64 mm
> >
> > At 0.56 keV (think that was where EE performance was spec'd) the EE  
> > due to diffraction is:
> >
> >   EE (per cent)		0.32 mm aperture	0.64 mm aperture
> > 			diameter (arc-sec)	diameter (arc-sec)
> > --------------------------------------------------------------------
> >
> > 	50			0.761			0.384
> >
> > 	68			1.125			0.569
> >
> > 	90			2.016			1.071
> > --------------------------------------------------------------------
> >
> > The first "zero" (real dark ring) in the diffraction pattern occurs  
> > at 1.46 and 0.72 arc-sec radius for the 0.32 mm and 0.64 mm  
> > apertures, respectively.
> >
> > Paul
> >
> > -- 
> > Dr. Paul B. Reid
> > Harvard-Smithsonian Center for Astrophysics
> > 60 Garden St.   M/S 04
> > Cambridge, MA 02138
> >
> > 617-495-7233 (voice)
> > 617-495-7356 (fax)
>