-----Original Message-----
From: Dan Dewey [mailto:dd@space.mit.edu]
Sent: Thursday, March 22, 2001 3:00 PM
To: Steve.O'Dell@msfc.nasa.gov
Subject: hetg rad exposure question


Hi Steve, 

 Where the HETG gratings that were exposed to radiation
exposed over the full grating area?  (e.g. 1x1 inch)
I figure they were but wanted to double check,

 -Dan


From: "O'Dell, Steve" <Steve.O'Dell@msfc.nasa.gov>
To: "'Dan Dewey'" <dd>
Cc: "Kolodziejczak, Jeffery" <Jeffery.Kolodziejczak@msfc.nasa.gov>
Subject: RE: hetg rad exposure question
Date: Fri, 23 Mar 2001 16:54:27 -0600


Dan -
It's good to here from you!  I hope all is going well.
Yes, the entire grating is exposed uniformly by raster scanning.  The
enclosed message (below) gives a little more detail.
- Steve


>From: "Semmel, Charles" <Charles.Semmel@msfc.nasa.gov>
>To: "Kolodziejczak, Jeffery" <Jeffery.Kolodziejczak@msfc.nasa.gov>
>Cc: "Edwards, David" <David.Edwards@msfc.nasa.gov>
>Subject: RE: Chandra grating proton irradiation
>Date: Fri, 23 Mar 2001 08:43:34 -0600
>MIME-Version: 1.0
>
>Hi Jeff,
>
>	We raster scan the beam when we do exposures.  The scanned area
>was probably three to four times the area of the sample. Each sample was
>placed in the center of the chamber so the entire area of the grating
>was covered.  This technique is used in ion implantation and provides a
>very uniform dose across the sample.
>
>	Did they see some non-uniformity?
>
>Chuck
>