Additional comments for civil design

[Elton Smith <elton@jlab.org>]

Hi Rebecca,

Below are a few issues that came up during the review but were not on your
list. I provide them here for clarification.

1. Need to add roll-up door size for Hall D. (Size of Hall B door is
15'x15')

2. There are drains in the tagger building and Hall D. We were asked if we
wanted any slopes in the floor to help drainage.

With installation of heavy loads we want the floors to be flat.

3. Radcon has made many requests to add shielding to the electron beam
dump area, particularly to prevent ground water contamination. To offset
cost increases they think that it is safe to reduce the length of the
electron beam dump tunnel. The current suggestion is to reduce the length
by about 16'.

We have reviewed the new proposal with Richard Jones and Radcon and agree
that the reduction of length from photon beamline to electron beam dump
will be acceptable in terms of backgrounds. A sketch has been provided to
clarify our understanding of the new configuration.

4. We need to provide guidance on the hole penetration in the steel in the
photon beam dump so that the beam is dumped deep inside the steel.

Request a square 6"x6"x40" hole centered on the nominal beam height into
the iron in the photon beam dump. (The square dimensions is only for ease
of stacking shielding, but it could be round).

5. Add estimates of vacuum levels both in the tagging system (<10^-3
torr) as well as the pipe between the tagger building and the collimator
hut (<0.1 torr).


Thanks, Elton.


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