[G12] farm local dsks

[Johann Goetz]

Hi Valery,
It would be almost trivial to run gflux twice once I have the skim done --
with and without trips taken into account. Indeed, I don't think any one is
looking for better than 10-15% systematic error on cross sections. Still, we
will have to investigate the effect of incorporating the trips in analysis
-- probably on a per-final-state basis.

On Thu, Apr 14, 2011 at 9:32 AM, Valery Kubarovsky <vpk at jlab.org> wrote:

> Sasha, privet!
>
> I have a simple question: do we need to use trip detection at all?
> Can you provide normalized to the flux yield (pp-+pi-, or any other
> combination)
> for selected with trip detector events and just for all events. I mean take
> all events with
> flux from the trip,  bad or good.
> Based on these numbers we can judge, do we need it or not. What do you
> think?
> g12 is not PRIMEX, we don't need very good absolute normalization.
>
> Valery
>
>
>
> On Wed, Apr 13, 2011 at 9:22 PM, Alexander Ostrovidov <
> ostrov at hadron.physics.fsu.edu> wrote:
>
>> On Wednesday, April 13, 2011, Eugene Pasyuk wrote:
>> > In your first example it is clear that trip detection failed the second
>> > interval should have status "0"
>> >
>>
>> Eugene,
>>
>> I'm getting an impression that if trip detection by sync followed by
>> tripFixer can so easily fail on such good looking interval then
>> it's even more likely to fail in many other places as well.
>>
>> Live time peak for this run 57129 is 0.8019 with a sigma of 0.0209
>> (Gaussian fit). The interval  I gave has LT of 0.813. It's well within
>> LT peak and should survive any  LT cut. Same story for the number
>> of events. Yet it was still marked as bad by sync/tripFixer.
>>
>> This is not an insignificant problem. Run 57129 which I looked carefully
>> at
>> contains 768 scaler intervals. Not a small run - about 2 hours of running.
>> 251 intervals are marked with status "1". By my eyeball  estimate, about
>> 150 of them look perfectly normal in terms of the number of events and
>> average live time. If "trip detection failed" in 1/5 of all scaler
>> intervals then
>> this should be of some concern, right?
>>
>> As I understood you, your suggested solution is to ignore interval's beam
>> trip
>> status after sync. Don't use tripFixer at all - what the point? Just
>> determine
>> LT threshold on per run basis, and use LT cut to correct interval status
>> in the trip files for all intervals (not just the ones merged together
>> from
>> previously split files). Is this that simple?
>>
>> Sasha
>>
>>
>>
>>
>>
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>
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-- 
Johann T. Goetz, PhD.
jgoetz at ucla.edu
Nefkens Group, UCLA Dept. of Physics & Astronomy
Hall-B, Jefferson Lab, Newport News, VA
Office: 757-269-5465 (CEBAF Center F-335)
Mobile: 757-768-9999
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