Review of Hall D shielding

[Elton Smith <elton@jlab.org>]

Hi Pavel,

We are updating the Hall D documentation for inclusion in the next version 
of the Design Report. This information will be used as input to the CDR 
for the 12 GeV upgrade. We believe that the relevant parameters for the 
layout have been agreed on, and are consistent with your model for 
radiation calculations around the Hall D building and site boundary doses.

Thanks for providing the calculations on radiation levels outside of Hall
D and at the site boundary with the new layout. I have included some of
your figures as well as text based on your e-mail into the chapter on
civil construction for the Hall D Design Report. As I have reworded the
text you sent me, please check it for accuracy (Section 7.3.7). We do not
expect any of the main dimensions to change, so it would be very useful to
summarize your calculations in a note which we can use for reference.

I am sending you a copy of the chapter on civil construction and the 
latest civil drawings via lab mail. Please review them and make any 
comments and suggestions, which we can use to update the 
drawings. At that point, we would like to produce a "final" set of 
drawings which can be signed off for the CDR. The intent is to send these 
off to a A&E firm for preparation of construction drawings at the 
appropriate time.

I will be glad to come by your office and review the drawings with you 
after you have had a chance to take a look at them.

Specific items to check:

1. We expect to reduce is the height of the Hall D building.  The drawings
presently indicate 11 m of "clear hook height". This will be reduce to 9
m, which I assume this will not impact the results of your calculations.

2. Shielding on top of tagger building. The drawings are presently 
inconsistent. Some say 4 m, other sections say 4.5 m. How much do we need?

3. Amount of shielding ontop of electorn beam dump. Chapter 7 indicates 1
m of steem and 5 to 6 m of earth. (I assume these numbers originally come
from Lew Keller). The drawing does not have any steel drawn and 4 m of 
earth. Please provide the shielding required for an update on the 
drawings.

4. Collimator enclosure. (Presently no section is shown; we need to add 
this to the drawing set). Chapter 7 suggests 1.2 m of steel and 1.7 m of 
earth. Please review these numbers to be added to the drawings.


Thanks, Elton.




-- 
Elton Smith
Jefferson Lab
elton@jlab.org
(757) 269-7625