From:	Nelson, Janice L.
Sent:	Tuesday, May 03, 2005 4:59 PM
To:	Himel, Thomas M.; 'Nicholas Walker'; Raubenheimer, Tor O.; 'Sebastian Schaetzel'; Phinney, Nan; Ross, Marc; Sheppard, John C.; 'Eckhard Elsen'
Subject:	topic for availability meeting
Hi All-

We've done some local research about how much a low current e+ source would help.  I recently "interviewed" a local SLC/PEPII operations expert, Mike Stanek, about a low current e+ source - how it would affect the running of the SLC and PEPII.  The questions I asked him obviously need further analysis with respect to ILC and may contribute to the discussion tomorrow morning.  My notes from the interview follow below.

Until tomorrow-
  Janice

I spoke with Mike Stanek about low intensity e+ source.  The questions I posed were:
how much PEP MD is done at low current?  Most of it (he implied >75%).

would a low-I source help feedback recovery? Probably not much - maybe a minute or two - depends on how the MPS is set up.

would low-I e+ in the south damping ring (SDR) during SLC have helped SDR recovery times after electrons come back?  Perhaps a little.  But if too low current, you don't get the nice warming effects of the synchrotron radiation.

How would a low-I e+ source help commissioning?  He thought it would take a year off the ILC commissioning time.  Also if no one builds a test undulator beforehand, then 2 years.

how often do they recovery from one problem only to find out that something broke in the mean time?  He said 3-5% of the time.  Many times another problem is found through the error displays so repairs are begun before the first repair is completed.

I told him about being able to watch low-I e+ on the final focus beam dump screen and would that have helped?  He thought that it didn't really matter if alarms/displays were better managed so that the 3% were noticed before.

He said that they no longer standardize the damping rings unless they're running low-emittance beam to FFTB.  PEP doesn't care.