[BTeam] B team this afternoon

[Jay Benesch]

Todd replied that he was out most of this week.  In particular:

> This is a fine topic for BTeam this afternoon --
> I'm also CC:ing Yves (who is master of the decks and matching) and Spata
> for their awareness. Please email the BTeam list noting that this is a
> topic for this afternoon's meeting so only those who are interested feel
> obligated to attend.

Mike Tiefenback replied in part:

> The typical phase shift was 5 or 7 degrees, but again that should be in the logged data files.  The dwell time was until the RMS settled until the RMS of three consecutive values settled to some level which I don't now remember, but it was not a fixed dwell time.
>
> We thought about making Krest less objectionable from the jitter standpoint (to the users) by making the phase shift in multiple small steps so the elock would make corrections gradually instead of hammering the elock in one bash, but execution time was always a concern

Net: If anyone shows up in the MCC at 1330 we'll discuss Phaser and arc 
1/2 dispersion.

Jay


-------- Forwarded Message --------
Subject: B team tomorrow
Date: Mon, 22 Jun 2015 16:29:44 -0400
From: Jay Benesch <benesch at jlab.org>
To: Todd Satogata <satogata at jlab.org>
CC: Chris Slominski <cjs at jlab.org>, Michael Tiefenback <tiefen at jlab.org>

Todd,

What's the agenda?  Failing any, I'd like to discuss putting the same
2.5 m dispersion optics in arcs 1 and 2 as in the higher arcs, to
facilitate phasing and gradient calibration in the presence of the linac
variation shown in

https://logbooks.jlab.org/entry/3344086
https://logbooks.jlab.org/entry/3344178

and the data Chris took during a brief test of Phaser, shown in the
spreadsheet attached.  The data attached was taken AFTER the first
application of Phaser to the two zones, so the positive and negative
phase offsets should have given equal variations.  They don't.  Phaser
kicks were pushing the beam into regions where the BPMs are non-linear,
but the BPMs should still be reproducible.  I don't understand, but if
the dispersion was 2.5m instead of 7.5m Phaser could make a larger dp/p
and get above the noise shown in the elogs.

Krest ran with 6 m dispersion.  I'm not sure what angle (or dp/p) was
used or how long the integration was at each phase offset.

Jay



-------------- next part --------------
A non-text attachment was scrubbed...
Name: Phaser_data.xlsx
Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Size: 9671 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/bteam/attachments/20150623/f1ae4400/attachment.xlsx>