Re: [BLAST_ANAWARE] sorry!

From: Peter Karpius (karpiusp@einstein.unh.edu)
Date: Wed Aug 21 2002 - 20:00:13 EDT


OK I have some comments,

> no, they are not off, but you should have told us it was in picoseconds..
>
At the top of the sample offset output sheet I handed out last week it
says the values are in picosec, I apologize for the confusion and should
have made it more clear when I had it on the overhead projector.
 
> I of course assume that you do all testing in some directory of yours
 
Yes, I am using a modified ntuple.C code in one of my own directories to
test the functions.
Currently however, the latest stuff is on my machine at UNH to avoid
network delay.

> you should use the value you measure for the total swing of propagation
> times in a tof (not a calculated values).

What exactly do you mean by the above?

>The offsets of course only
> change the value of the center channel and care must be taken to define
> the center channel. You should use the median value (which you know once
> you now the width of the distribution).

Yes, I am a bit worried about the center channel definition with regards
to binning and how I set limits on criteria for redefinition of
offsets when reading the the central value (I'll explain this in more
detail in the future). But yes I am using the Median as defined using the
method I outlined last week.
 
> now *for the future* there is an issue in how to ensure backward
> compatibility for the analysis of new/old data for which some channels
> end up being plugged to different new/old modules... (different offsets)
> It could happen anytime (in the next 3 years?) and in either case we have
> to make sure we use the right offsets.

Yes I agree, that is why I am trying to set it up so that it can write the
offsets directly to the calib file so this does not have to be done by
hand. It could be set up with a time stamp and rename the calib file each
time it is run. I would say that, whatever we do for the electronics map
we should do for the calibration file. Do you agree?
 
>Will you put this in the database ?

That is on the list!

        Thanks for the comments, I will keep hammering away at it-
        
                                        Pete



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