Re: skimmer question

[Steven Clayton <smclayto@npl.uiuc.edu>]

On Tue, Jan 31, 2006 at 02:48:44PM -0800, Frederick Gray wrote:
> On Tue, Jan 31, 2006 at 04:03:22PM -0600, Steven Clayton wrote:
> > Hi Fred and Tom,
> > 
> > I think I understand your (Fred's) point about the edges
> > of the skimmed region being problematic for pileup-protection.
> > Say the muSC hits are the X's on the following (absolute) timeline:
> > 
> > <--X-----------X--------X--><--X-----------X----------------X-->
> >        |       |       |           |       |       |
> >      100us   125us   150us       1000us  1025us  1050us
> >
> 
> Hi, Steve,
> 
> Yes, thanks for making this argument for me.  I was having trouble 
> reconstucting it on the phone this morning.  The point is that you don't
> know whether or not your first, third, fourth, and fifth hits are
> pileup-protected.  Maybe, maybe not; the information you would need to
> determine that has been thrown away.
> 
> In the main skimmed data production that you are using, I solved this
> problem by only keeping muSC hits (parameters 6000-6099) over the 25
> microsecond interval, while keeping all other hits for the longer 40
> microsecond interval. 
> 
> A more recent version of the skimmer (not yet widely used) renames 
> parameters 6001-6019 as 6021-6039 when they are outside the 25
> microsecond interval.  
> 
> The "general skimmer" currently ignores this problem, since I envisoned it as 
> primarily useful for making event displays of selected events, where you
> would like to see the full context over the interval that you choose to save.
> 
> Thanks,
> 
> -- Fred
> 
> -- Fred Gray / Visiting Postdoctoral Researcher                 --
> -- Department of Physics / University of California, Berkeley   --
> -- fegray@berkeley.edu / phone 510-642-2438 / fax 510-642-9811  --

Hi Fred,

regarding the "general skimmer," could you simply define an extra
parameter as "skim interval start" and another as "skim interval stop,"
and merge these into the HITS bank?  I think Peter's intention is to
actually do the Alvarez search on loosely-triggered skimmed data,
in which case we need to know which entrances are good.

Thanks,
Steven