Distribution:

Gordon Bowden	17
Hobey DeStaebler	17
Jonathan Dorfan	17
Stan Ecklund	17
F. Forti	INFN-Pisa
Fred Goozen	LBL 50-137
John Hodgson	12
Roy Kerth	LBL 50-340
Tom Mattison	17
Martin Nordby	21
Natalie Roe	LBL
John Seeman	17
Mike Sullivan	17
Dieter Walz	20
U. Wienands	17
M. Witherell	UCSB Physics
Dept.
M. Zisman	LBL 
M. Zolotorev	55

15 February 1995
To: Distribution:
From: Hobey DeStaebler
Subject: "IR +- 1m Engineering"  Meeting Notes 10 February 1995

Dieter reported on He gas cooling of Be beampipe (see transparencies;
also a corrected sheet to replace p.4 from last week).  He also looked
at other liquids like oil (no--too viscous), or ethylene glycol (OK).
He also looked at Tom's suggestion of 6 external pipes to fit into the
notches of the hexagonal Si; possible, but doesn't look great.

John realized he can handle the cross talk problem, but no results yet.

Mike says an LEB SR mask with 3 tips rather than 2 is OK. Still have to
look in detail at SR scattering.  Completely removing the Q4 offset
doesn't work because quad SR from Q5 hits the IP side of the LEB SR
mask.  Perhaps reducing Q4 offset would be possible.  But SR from B2
not now taken into account.

Gordon estimated the required sizes of SmCo shims to go on the outside
of the slices to trim the harmonics (roughly 1 mm thick).  These would
be in addition to tuning the blocks with set screws before bonding in
place, and rotating slices slightly to optimize the angle of the
harmonics.  Need required tolerance values to work on this in more
detail.

Hobey showed how to estimate the resonant frequency of the support barrel
(see transparencies).

Action Items:
1. Refine the CAD drawing with proposed changes.
   Add imported vertex drawings. [Martin]
2. More thermal calculations of mask-B1 cooling. [John H.]
3. Number and location of holes in support barrel. [Gordon]
4. B1 mechanical construction and space requirements. [  ]

attachments: Transparencies.
    Gordon's transparencies--next week
    Mike's also

Next Meeting: 13:00 Friday  10 February 1995 in the Yellow room with TV to 
LBL

Agenda:  Status Reports for action items.