[Clas12_first_exp] New, more complete studies of spring and fall luminosity scan runs

[Stepan Stepanyan]

Hi FX,

I have not looked on CD tracking efficiency from your latessed cooking, I can of course. The proposed increase is ~20%, I do not think DC HV will let us to go much higher than that. I am not sure such increase will mess to much CD tracking, but of course we need expert's opinion, and evry one else's.

Regards, Stepan

----- Original Message -----
From: "Francois-Xavier Girod" <fxgirod at jlab.org>
To: "Stepan Stepanyan" <stepanya at jlab.org>
Cc: "clas12 first exp" <clas12_first_exp at jlab.org>
Sent: Sunday, October 28, 2018 3:45:59 PM
Subject: Re: [Clas12_first_exp] New, more complete studies of spring and fall luminosity scan runs

Dear Stepan, all

In previous studies there was an increase of the number of tracks in the CD
presumably due to accidental hits. Should this enter in consideration for
the choice of RG-A luminosity? Is there any feedback from CD tracking
experts on this? Can we already assess the quality of additional tracks
with the current alignment? Having too many tracks may not be an issue for
exclusive reactions, but that is assuming we do not lose tracks. For
semi-inclusive physics, this sounds a bit more dangerous.

Best regards
FX

On Sun, Oct 28, 2018 at 3:02 PM Stepan Stepanyan <stepanya at jlab.org> wrote:

> Dear all,
>
> I just posted a presentation with studies of forward detector charged
> particle reconstruction efficiency as a function of beam current. I used
> both spring and fall luminosity scan runs, processed with latex CoatJava
> (or almost latest). Results are not so different than what we had from
> August studies. We should dig deeper to understand where the looses come at
> high currents and see if we can mitigate these losses with. I see few
> options to explore. In the mean time, I propose to increase beam current
> for production runs for the remaining of the RG-A run to max allowed value
> defined by safe operations of detectors. From what I can see from DC
> currents, we may be able to go to 55 nA.
>
> Regards, Stepan
>
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