[Bteam] notes from today's meeting

[tiefen at jlab.org]

On Wed, 18 Nov 2009, Arne Freyberger wrote:

>     1.3 Viewer limited BPMs Tief
>
> Proposal to adjust the timing of the viewer limited beam pulse so that the 
> BPMs work during viewer limited mode.
>
>   * Summary
>     Viewer limited pulse is 10 ? s
>
>     This will require better timing on BPMs?

Where did this question on BPM timing come from?  I've asked to put the 
viewer limited pulse in sync with the linac 4-usec trailer.  There is NO 
requirement for BPM timing changes, only to sync the viewer limited pulse 
with the 350-usec delayed trailer instead of having it occur at beam sync 
zero.  If this were done and the viewer limited pulse were selected to 
have a 4 microsecond duration, then the linac bpms would light up in 
multipass mode to guide steering of the beam at reinjection through the 
linacs instead of tripping RF after a few seconds (or milliseconds).  The 
ability to do this was important during commissioning of CEBAF at 4 GeV, 
and was frozen out by a "let's keep the operators from making errors" 
philolophy of severely restricting options for pulse structure.  We're 
going to need it again, and we would have benefited from it in the recent 
past.

>
>     Delay viewer limited pulse.
>
>     Take it up next week.
>

I'm sorry to have been ill.  It would have been useful for me to explain.

>
>     1.4 FY10 projects ALL
>
> Any thoughts on what Bteam wants to accomplish in FY10. There are two downs 
> in FY10, Jan/Feb Winter down and the July/Aug Summer down.
>
>   * Continue/complete BSY diagnostic suite?
>         o viewers in front of dumplettes
>         o move more harps?
>   * Open to ideas
>         o halo detector in BSY

Good idea.

>         o finish the matching algorithm. Prove that our present
>           diagnostics and software provide a good match which is
>           verified by downstream harps.
>         o Continue/finish ODR R&D in Hall-A
>         o get undulator from Darsburry and put in a chicane. Can tune
>           to different energies, so in the linac one can measure beam
>           size of all five passes. Need a meter at the end of linac in
>           12 GeV and a new vacuum chamber in the BCOM.

How is this better than a wire scanner profile monitor?  Is the 
improvement to allow measurement at full CW beam current?

>         o Replace 5 MeV dipole. Retain -12.5, -30 degree ports, and
>           +12.5 or +30 degree ports. Magnet, vacuum chamber, power
>           supplies. Horizontal gap is XXX? Does ISU have such a
>           magnet? What are the field requirements? What are the space
>           limitations?
>
>
>     1.5 Optics-on-call
>
> Outgoing
>   Mike Spata, Geoff Krafft Incoming
>   Alex Bogacz
>   * Program
>         o Production running in A and B
>         o Possible Compton optimization
>         o Thaw the turkey

We never did a real test of the reduced buncher configuration that Reza 
tuned up and which looked much more like "old times" behavior than the 
present configuration does.  The "bunch length" process which is used to 
characterize bunch compression mangled the settings when it "restored" to 
canonical phases rather than to the as-found phases when it was turned on. 
When we tried to transport beam through the Compton Chicane, conditions 
were not as they were when optimized.  I think this should get a re-check.

>
> Date: 2009-11-18 15:45:00 EST
>
> HTML generated by org-mode 6.32trans in emacs 23
>
>
> -- 
> Arne Freyberger
> Director Operations Department
> Jefferson Lab           Phone: (757) 269-6268
> 12000 Jefferson Avenue  Pager: (757) 584-6268
> Newport News, VA 23606  Email:  freyberg at jlab.org
>
>