MIPP TPC Optics Bay

Where Is This?

The optics bench and upstream window of the TPC:

The outer re-entrant window (most of what you see in the right-hand picture) will be removed for MIPP.

Measured Window Geometry

Measurements made 2/10/03 with the outer reentrant window off, using a tape measure (probably good to ±0.032").

Relevant LBL Drawing Details

 Relevant LBL Mechanical Drawings are:

1. OUTER REENTRANT WINDOW ASSEMBLY
2. OUTER MATING FLANGE
3. OUTER ADAPTER FLANGE
4. GAS JACKET PARTITION
5. INNER REENTRANT ASSEMBLY
6. HISS TPC Component Locations (Sht 3)
7. FIELD CAGE PENETRATIONS
8. LASER TRACK COORDINATES

These show the following:

Outer Window Flange - Bolt Circle:

18 x 10-32 on 17.250 diameter, consistent with measurement above.

Outer Window Flange - Inner Diameter:

Dimension ranges from 13.910&endash;15.000. Latest detailed drawing, #3 in the list above, shows 14.778 diameter.

Outer Window Flange - Outer Diameter:

18.000 diameter, consistent with measurement above.

Depth to Window:

1. 15.530 to outer re-entrant window back surface.
5. 3.125 between front surface of inner window flange and inner window sill, consistent with the measurement above.

Possible Target Changer Mounting

Suggestion: use the outer window flange bolt circle as the mounting surface. One could insert the gizmo and bolt it up, then turn a crank to advance it to the desired position.

What should the final position be? Probably we should stop at the front surface of the inner window sill front surface, 15.156" from the outer window flange.

 Nominal Beam Position Within The Window

Ingrid's TPC Cart positions the TPC as low as possible. This still results in an offset between the nominal beam position and the port centerline. Our beam will be 1.168" above the port centerline.

In the HISS magnet at the Bevelac, this offset was 0.500".