Thought I would share the livetime plot from run #5495 with the rest of the
audience...
Quoting Tancredi Botto <tancredi@lns.mit.edu>:
>
> Well,
>
> running with the CC in the een trigger, as suggested friday, cut the
> deadtime by a factor of 2, as can be seen in the first attachment
> (red/green point vs black). Nothing changed on the ep trigger so the CC
>
> efficiency can be determined from there. The new file trigger is called
>
> tb.settings - for the time being. It also fixes a minor bug.
>
> So presently, we can run < 20 % up to 80 mA (true singles - with CC -
> are
> effectively prescaled by 15). On friday I was quite convinced that the
>
> "breaking point" in the deadtime vs beam distribution somehow had to do
>
> with beam tune and beam blow up, although I could never find evidence in
>
> the lifetime for that.
>
> Then 2nd attach: livetime vs accepted rate. As predicted by Karen and
> discussed in the hall-B NIM paper at about 400 Hz we max out on
> bandwith.
> The solution - for the higher currents - is to go to fast ethernet,
> which
> requires additional fastbus modules. In the meantime we can reduce the
> event sizeby running the ADC thresholds
>
> However, it is also true that 2/3 of the events are trackless, and a
> vast
> majority of those that track are low-energy "junk" and that this is
> attributed to the collimator. In my opinion this is the most important
>
> item. Also because at this rate sooner than later we are going to fill
> up
> our disks with useless junk.
>
> --
> ________________________________________________________________________________
> Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
> research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
--------------------------------------------------------------------------
Eugene Geis
PhD Student, Physics Department, ASU
Research Affiliate, MIT-Bates Laboratory of Nuclear Science
eugene.geis@asu.edu
--------------------------------------------------------------------------
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