Notes from Main Injector/Recycler Group Meeting
Wednesday, 18 September 2002
Bruce C. Brown

Proton Studies of R22 Transfer Line - Cons

With conditions found recently, it was observed that the transfer
efficiency as tuned up was 80-85% of RR beam circulating in MI [have
since achieve >90%].  It was found that inserting 4 planes of
multiwires caused a further 15% transmission loss.  The two skew
quadrupoles in this line have been tuned to improve transmission and
turning them off resulted in only about 50% transmission.  Turning off
the skew quads causes saturation losses at LM221 (location of MI
Lambertson).

Using the multiwires it is observed that there is lots of quad
steering.  Resteering with quads off results in regaining most of the
transmission but the loss monitor readings are still quite high.  The
difference in closure is small.  Today, with skew quads on, the MI
flying wires measure about 11.7 pi-mm-mr before transfer to RR and 18
pi-mm-mr when returning to MI.

With the best tuneup achieved at this time, the positions in the Main
Injector are much different than designed.  The measured (design)
values are HP222 = 12 mm (20 mm) while VP221 = -6 mm (0 mm).  This is
interpreted to show that the line is not as expected and additional
study is required.  

Discussion: The most recent survey data must be examined (if not
adequate, request additional survey).  Ming-Jen Yang has added the
required information to I90 (or R90) for the new magnets and
instrumentation and is ready to proceed with more refined
measurements.  Bill Foster observed that, using the centroid
measurements from the new multiwires, one can now document the source
of skew fields which we have, up to now, assumed were in the Permanent
Magnet Lambersons.

Sequence Aggregate Enhancements - Cons

Some of the new sequencer aggregates were discussed.  Cons has added
some tutorial material about the aggregates which can be activated by
clicking on title information.  Lots of changes are underway most of
which are involved with longitudinal manipulations.  These are
currently set up to be checked out with protons but minor
substitutions will make them perform the stacking and unstacking
operations with pbars.  Pictures of unstacking were shown.  It was
obvious that the longitudinal emittance was too large to permit capture
in the available 2.5 MHz bucket.  Not a surprise (per John Marriner).
Currently they are prepared to check the approximate pbar timing of
the R400 kicker using protons.

Plans and Discussion - Shekhar

Expect to ask for pbars next week, beginning with transfers from the
bottom of the stack to confirm the sequence rf developments described
above.  Probably will divide the remaining 10 mA into 3 mA transfers.
Developments are underway for SDA descriptions for the Acc -> RR
shots.  

Tomorrow there is a meeting with the LLRF developers (Brian and Keith).
The worklist [in priority order]:
    Developments of MI LLRF for coalescing (operations)
    RR LLRF changes (with J. Marriner and C. Bhat)
    R&D  
	 Frequency Shift in RR - consider using LLRF feedback
              [develop measure of centroid of beam in barrier bucket]
	 Slip Stacking in MI
	 Fast RR Stacking 
	      [wave form needs to morf in an as yet unsupported way]
	 2.5 MHz Pbar acceleration in MI (is software ready? Need RPOS)

Note that these item include things in addition to Keith and Brian's list.