[Primexd] [GlueX] Target installation plan

[gasparan at jlab.org]

  Dear Matt and All,

 At this stage it is clear that we should survey entire beam line,
 for sure including the FCAL (not only CCAL).

 The question is what to do next.

 Ashot


>
> Liping,
>
> Without survey I cannot definitively assert that it did not move, but it
> would be really really really hard for the FCAL to make a significant
> horizontal movement.  I just isn't that mobile.
>
> Matt
>
>
>> On Feb 28, 2019, at 3:35 PM, Gan, Liping <ganl at uncw.edu> wrote:
>>
>> Hi, Matt,
>>
>> Do you know if FCAL position has been changed since 2015 survey?
>>
>> Liping
>>
>> From: GlueX-Collaboration <gluex-collaboration-bounces at jlab.org> On
>> Behalf Of Simon Taylor
>> Sent: Thursday, February 28, 2019 3:23 PM
>> To: Ilya Larin <ilarin at jlab.org>; Shepherd, Matthew
>> <mashephe at indiana.edu>; Ashot Gasparian <gasparan at jlab.org>
>> Cc: primexd at jlab.org; andrsmit at jlab.org; GlueX Collaboration
>> <gluex-collaboration at jlab.org>; Mark Stevens <stevensm at jlab.org>
>> Subject: Re: [GlueX] Target installation plan
>>
>> For what it's worth, according to the 2015 survey (I am not sure if the
>> FCAL was resurveyed at a later date), the FCAL as a whole is off in x by
>> about +5mm, but only a tiny amount off from zero in y.
>>
>>
>>
>> In the attachment the highlighted numbers are z,x,y in meters.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> Simon
>>
>> From: GlueX-Collaboration <gluex-collaboration-bounces at jlab.org> on
>> behalf of Ilya Larin <ilarin at jlab.org>
>> Sent: Thursday, February 28, 2019 2:58:38 PM
>> To: Shepherd, Matthew; Ashot Gasparian
>> Cc: primexd at jlab.org; andrsmit at jlab.org; GlueX Collaboration; Mark
>> Stevens
>> Subject: Re: [GlueX] Target installation plan
>>
>>
>>
>>  Hi Matt,
>>
>>
>>
>> according to the pictures the square pipe is asymmetrical vs beam line
>>
>> and is most likely causing the "shade" on ComCal face.
>>
>> Wondering if  FCAL is placed symmetrically vs beam,
>>
>> that should mean that pipe doesn't exactly match FCAL hole.
>>
>> The exact values from drawings would help and needed for MC
>>
>> geometry db to get an exact acceptance.
>>
>> If it is the case, that only mean we have to reduce ComCal
>>
>> fiducial region for Compton events.
>>
>>
>>
>>  Thanks for pictures.
>>
>>
>>
>> Ilya
>>
>>
>>
>>
>>
>> От: GlueX-Collaboration <gluex-collaboration-bounces at jlab.org> от
>> имени Shepherd, Matthew <mashephe at indiana.edu>
>> Отправлено: 28 февраля 2019 г. 12:49
>> Кому: Ashot Gasparian
>> Копия: primexd at jlab.org; andrsmit at jlab.org; GlueX Collaboration;
>> Mark Stevens
>> Тема: Re: [GlueX] Target installation plan
>>
>>
>> Hi Ashot,
>>
>> > On Feb 28, 2019, at 11:58 AM, gasparan at jlab.org wrote:
>>
>> > Therefore, it would be extremely important to take pictures of the
>> FCAL
>> > insertion part and post on some place to see, before our meeting this
>> > evening.
>>
>>
>> I've posted pictures of the FCAL insert here:
>>
>> https://logbooks.jlab.org/entry/3661206
>>
>> It looked today exactly as it did 5+ years ago when these were taken.
>> (I'm surprised you haven't taken a peek at it before as it defines the
>> acceptance of your detector.)
>>
>> The Plexiglas monitoring system is held in the groove on the upstream
>> end.  Anything of any density should be clear of the inner opening in
>> the tube.  From the darkroom all that is visible is what appears to be a
>> thin tedlar cover on the upstream end.  It is needed for a light seal or
>> else there is light path from the hall into the darkroom via the beam
>> pipe.
>>
>> Matt
>>
>> ---------------------------------------------------------------------
>> Matthew Shepherd, Professor
>> Department of Physics, Indiana University, Swain West 265
>> 727 East Third Street, Bloomington, IN 47405
>>
>> Office Phone:  +1 812 856 5808
>
>