[Hallc_sidis_analysis] SIDIS analysis

[bosted at jlab.org]

I think I found the reason that the rate of good coincidences was dropping
at higher SHMS singles rates. It turns out that we forgot to adjust the
time window gate of the trigger TDC's: it has been very wide (about 1500
nsec, whereas it should be less than 100 nsec). Mark is going to adjust
them and hopefully that will solve the problem.
Peter

> ---------- Forwarded message ---------
> From: <bosted at jlab.org>
> Date: Wed, Oct 31, 2018 at 4:26 PM
> Subject: Re: [Hallc_sidis_analysis] SIDIS Analysis meeting
> To: Dipangkar Dutta <ddutta07 at gmail.com>
>
>
> Hi all,
>    Just to note: one cannot determine the HG efficiency from
> the number of events above a threshold (say 2 pe) because we
> don't have any momentum for which the kaons are below threshold in both
> the aerogel and the HG. In other words with momenta of 3.3 to 3.7 GeV as
> we have for run 5415 (central momentum 3.44), requiring a signal in the
> aergel does not eliminate the kaons (threshold 2.85 GeV in the aerogel).
> the pion threshold in the HG is 2.65 GeV, by the way.
>   So, I would rely on the HG spectrum: fit a Poisoon districbution to the
> n.p.e. peak, and calculate the number with less than say 2 pe. It will
> be very small.
>    IF we got very good timing as in the Spring, you can use cointime to
> also help discriminate pions and kaons even at 3.5 GeV.
>    Or you could use some runs from the first day (Monday) when we had the
> 1.011 aerogel tray (threshold for kaons 3.4 GeV). However, this is only
> 60 cm wide by 90 cm tall, so you can't use these runs to see the hg
> efficiency outside of this range.
>    Yours, Peter
>
>> Hi All,
>> We will have the regular SIDIS analysis meeting today at 3:00 PM EST.
>> The Meeting URL is
>>
> https://urldefense.proofpoint.com/v2/url?u=https-3A__bluejeans.com_648672553_&d=DwIBaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=JJJGXsp3RyGqlBjHKoZBjiaUCJFClUe6LQVUwbzc5OQ&m=h7hqVZJBtNr2Rmp9MJ_mg8uwCKZIvtKy2oWPPV11czE&s=d0mYWgqtsqN1hee7IRffBPOdfhk2UF2GgyB-lIyVL9o&e=
>>
>> Please plan on showing a few slides on your work and please upload the
>> slides to the wiki:
>> https://hallcweb.jlab.org/wiki/index.php/SIDIS#Weekly_Meetings
>>
>> Cheers
>> Dipangkar
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>>
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