24 February 1995
To: Distribution:
From: Stan Ecklund
Subject: "IR +- 1m Engineering"  Meeting Notes 24 February 1995

Mike Sullivan gave a status report on the attempt to reduce the 
offset of Q4.  Reducing the offset will cause fewer bremsstrahlung 
electrons to be steered into the detector.  He is finding that 
more of the synchrotron radiation intercepts on or near to the Be 
beam pipe causing a radiation problem for the silicon.  The HEB is 
worse because of the higher energy photons.  Large emittances will 
likely be a problem with a reduced Q4 offset.

We discussed the three tip mask and the possibility of moving some 
of the magnet material to smaller radius.  The three tip mask 
allows some of the B1 magnetic material to be moved to smaller 
radius.  This can be used to reduce the outer radius, relieving 
the interference with the vertex detector cone,  or increasing the 
bend angle of B1 making the septum quads Q2 and Q4 easier.

Increasing the ring energy ratio, e.g. 9.2/3.05 vs. 9/3.1,  also 
would reduce the septum quadrupole difficulty.

Action Items:
1.  Refine the CAD drawing with proposed changes.
    Add imported vertex drawing.
    three tip mask and allowed smaller radius B1 [Martin]
2.  More thermal calculations of mask-B1 cooling with actual 
    geometry when available.  [John H.]
3.  Number and location of holes in support barrel. [Gordon]
4.  Resolve conduction to cooling tube discrepancy [Dieter, Tom]
5.  HOM RF calculations with new mask geometry [S. Heifets]
6.  Contact Cornell (Stu Henderson) for Be corrosion information.
7.  Design mask with cooling and B1 to avoid interference with 
    vertex detector cone if possible [Martin] .

attachments: Transparencies

Next Meeting: 13:00 Friday  3 March 1995 in the Yellow room with 
TV to LBL

Agenda:  Status Reports for action items.