[g13] Fwd: run range to run: ST and TOF

[Daria Sokhan]

Hi Yordanka,

Perhaps this is a false alarm, in which case apologies for raising
concern, but if this is based on the monitoring histograms (from
anamon) then I distinctly remember that about two years ago I was also
concerned by the 0.7 ns peak, and after a lot of investgation it
turned out that this was due to some offset (target center at
different position or something similar), there for historical
reasons, in what the histograms were plotting, and not an actual time
shift in the data at all. I can look up the exact details in my lab
book when I am back in Orsay next week, and a bit earlier today I
forwarded a long correspondence with Franz and Eugene on the matter of
what the monitoring histograms actually show to Chuck as he was asking
about more info on that, I'll also look into that. But I remember that
the 0.7ns offset was a misleading issue! I am not sure whether
anything had been changed in the monitoring hists since then, so I
don't know whether this applies to the current concern.

Thanks,
Daria



On 9 June 2010 15:51, Yordanka Ilieva <jordanka at jlab.org> wrote:
> Dear Nick,
>
> I checked the histograms monitored for ST and TOF for run 54740_A00
> which belongs to the run range below (no Tagger entries). Both detectors
> have produced valid data. The monitored distributions Delta_T in both
> cases look OK, but are shifted from 0. The ST Delta_T for protons peaks
> at ~ -0.67 ns which falls out of the range +-0.5 ns that I chose for the
> timelines discussed yesterday during the meeting. Thus, there were no
> entries for this run range on the figures. The SC Delta_T peaks at ~+0.7
> ns. At this point the TOF calibration should be improved for this run
> range after Danny worked on it. I think, it makes sense to recalibrate
> ST only after it is confirmed that the tagger has produced data. It is
> interesting that SC masses have been reconstructed in the anahist file
> for the above run. I am not certain if this means there were valid
> tagger times found or the procedure allows to calculate beta, and
> therefore, the particle mass without the tagger.
>
> Regards, Yordanka
>
> Nicholas Zachariou wrote:
>> 54730--54770
>>
>> Nicholas Zachariou
>> nickzachariou at gmail.com
>>
>>
>>
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--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Daria Sokhan
Institut de Physique Nucleaire
Bat 100 - M055
Orsay 91406                              tel: +33 1 69 15 45 00
France                                      fax: +33 1 69 15 64 70
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~




-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Daria Sokhan
Institut de Physique Nucleaire
Bat 100 - M055
Orsay 91406                              tel: +33 1 69 15 45 00
France                                      fax: +33 1 69 15 64 70
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~