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Re: Phase II
On Wed, 16 Jan 2008, George Lolos wrote:
Dear George,
> Date: Wed, 16 Jan 2008 12:17:40 -0600
> From: George Lolos <George.Lolos@uregina.ca>
> To: Elke-Caroline Aschenauer <elke@jlab.org>
> Cc: Zisis Papandreou <zisis@uregina.ca>, zorn@jlab.org,
> Fernando J. Barbosa <barbosa@jlab.org>, halld-cal@jlab.org
> Subject: Phase II
>
> Hi Elke:
>
> First, can I ask you a small favour? When you reply to an e-mail but
> you change the subject material, like the one below, can you also change
> the subject title? It makes identification of pertinent material much
> easier both on selecting for prompt reading and later on when one
> searches for content.
you can always ask for a favour. I will just not promise that it will always
be so easily fulfilled as this one ;)
>
> I agree with you on the fact that right now the main issue is the
> non-uniformity of gain among cells in an array and among arrays. So
> having the emphasis on these makes a lot of sense.
>
> Some more specific comments, below:
>
>
> Elke-Caroline Aschenauer wrote:
>
> >On Tue, 15 Jan 2008, Zisis Papandreou wrote:
> >
> >Dear all,
> >
> >I think we have to make progress on the SoW with sensl. I went through the
> >contract and it looks much more resonable compared to the one before.
> >For the moment they leave the increase of PDE out, which I think is
> >reasonable and is what was suggested to Calr Jackson the last time.
> >Becuase having SiPMTs in hand which ave no gain variations, low noise and
> >cross talk, good electrical behaviour and timing structure woule be
> >extremely important. The increase in PDE can follow.
> >I like a lot that they will provide for quite some points test samples
> >which allow readout of the individdual 3x3 SiPMTs in the array.
> >
> >I have only very little points for a discussion.
> >
> >Page 6 point 3 WP1
> >---> after the results of Carl Zorn on gain variations vs bias voltage do
> > we consider a value of 10% inside one module adequate. I do not.
> >
>
> If the gain variations within cells of an array remain within 10% I
> don't see the problem. I miss the connection to your statement about
> bias variation. As long as the cells exhibit maximum 10% variation in
> gain, what does the bias voltage mean? Maybe I didn't understand your
> comment?
Oh correct, I misread in the proposal it is 10% in gain uniformity not in
breakdwon voltage. That is indeed fine.
>
> >page 6
> >---> I would like a detailed list of what intensive electrical and optical
> > tests mean and which test addresses which problem
> >
>
> I agree. The only obvious connections are the definition of breakdown
> voltage and whether a wafer and/or cell show a higher dark current than
> others, indicating poor Si or treatment.
>
> >
> >---> I see no mention of the integration of the temperature stabilisation
> > in the electronics.
> >
>
> I am baffled by this so I must have missed something. If we don't go
> with cooling, as we all agree, how can we stabilize the effects of
> temperature variations with electronics alone?
>
George, you have been also tired yesterday evening. I mix gain and break
down voltage and you mix cooling and temperature stabilisation.
We have been always saying we don't want to cool to -10^oC to get the dark
counts down, but to keep the gain and dark count stable we might have to
keep the temperature stable at room temperature or slighly above. Because
even if we reach a stable temperature in the hall the situation at the
location of the SiPMTs and especially from SiPMT to SiPMTs might not be
stable.
> >
> >the only other question are 5 arrays per setting enough, I would think so.
> >
> >In addition ot the SoW with Sensl, we have to start thinking about
> >spcifications for the glue, lead and all other material that is needed to
> >build the modules.
> >
> We had looked at other (cheaper) epoxies for the matrix of lead and
> SciFi. However, we could not find any obvious advantages over the
> BICRON 600 we have been using and KLOE also used. We know BICRON 600
> has good strength and does not chemically attack the SciFi material so
> we have long concluded on BICRON 600. As for the lead, what do you
> mean? We have submitted test reports clearly stating we need pure lead
> because any alloying results in problems with swaging. What we do need
> to resolve is whether we change the sampling fraction of the first
> couple of layers or not. So, in my opinion we have specifications for
> all items needed for construction.
>
George, no doubt we know what we want but we need to place orders with the
vendors, for the glue it might be so easy as just ordering BICRON 600 if
there is nothing else on the market which fits, than we need a sole source
justification for this, not a big deal but needs to be written.
For the lead I know you want pure lead also fine, but we have again to
order it so we have to write what ppm of other material is acceptable, we
need to think what proof we want of the producer that the lead is really
pure lead and so on and so on. Nothing complicated, but we have to do this
to avoid changes of properties during a production process and than the
company saying oh you did not specify that this ammount of copper in the
lead will cause problems, please reorder.
Nothing big just to make sure we will have a smooth bcal production.
bye bye elke
>
> Cheers,
>
> George
>
> >
> >Can we actually progress with the fiber specifications, Elton do we have a
> >list of measurments we need from the bicron and kuraray fibers we ordered.
> >
> >That is all I have for the moment.
> >
> >
> >
> >
> >
> >
> >
> >>Date: Tue, 15 Jan 2008 17:17:42 -0600
> >>From: Zisis Papandreou <zisis@uregina.ca>
> >>To: Hall-D Collaboration <halld-collab@dustbunny.physics.indiana.edu>
> >>Subject: [GlueX] Calorimetry Group Meeting - Jan 18
> >>
> >>Hello folks:
> >>
> >>I have two issues in this email.
> >>
> >>1. Day of the week and time of our periodic Calorimetry Group
> >>Meetings. There is a suggestion from JLab to reserve Friday's at
> >>10-11am for our meetings. This does not mean that we will have a
> >>meeting every week, it is just that we are trying to find a time that
> >>works for all active participants of our group, considering the 8
> >>time zones between Regina through the East Coast to Athens (9 in the
> >>summer, but we will revisit this at the time).
> >>
> >>Please let me know if this time slot does not work for you.
> >>
> >>2. I would like to schedule a meeting this Friday, Jan 18, so please
> >>reply to question 1 right away. The meeting is tentatively scheduled
> >>for 10am, unless I hear an uproar. The main topic is the work
> >>towards the Calorimetry Document, but other issues can be discussed.
> >>
> >>http://www.jlab.org/Hall-D/software/wiki/index.php/January_18%
> >>2C_2008_Calorimetry
> >>
> >>Cheers and thanks, Zisis...
> >>
> >>---
> >>Dr. Zisis Papandreou | email: zisis@uregina.ca
> >>Department of Physics | tel. : (306) 585-5379
> >>University of Regina | tel. : (306) 585-4149
> >>Regina, SK S4S 0A2 | fax. : (306) 585-5659
> >>World Wide Web: http://www.phys.uregina.ca/sparro/zisis/
> >>
> >>
> >>
> >>
> >>
> >
> > ( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
> > ) `\ -
> > / '. | +
> > | `, Elke-Caroline Aschenauer =
> > \,_ `-/ -
> > ,&&&&&V Jefferson Lab +
> > ,&&&&&&&&: HALL-D 12C / F381 121-A Atlantic Avenue =
> >,&&&&&&&&&&; Mailstop: 12H5 Hampton, VA 23664 -
> >| |&&&&&&&;\ 12000 Jefferson Ave +
> >| | :_) _ Newport News, VA 23606 Tel.: 001-757-224-1216 =
> >| | ;--' | Mail: elke@jlab.org Mobil: 001-757-256-5224 -
> >'--' `-.--. | +
> > \_ | |---' Tel.: 001-757-269-5352 =
> > `-._\__/ Fax.: 001-757-269-6331 -
> > +=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+
> >
> >
> >
>
>
>
( `,_' )+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=
) `\ -
/ '. | +
| `, Elke-Caroline Aschenauer =
\,_ `-/ -
,&&&&&V Jefferson Lab +
,&&&&&&&&: HALL-D 12C / F381 121-A Atlantic Avenue =
,&&&&&&&&&&; Mailstop: 12H5 Hampton, VA 23664 -
| |&&&&&&&;\ 12000 Jefferson Ave +
| | :_) _ Newport News, VA 23606 Tel.: 001-757-224-1216 =
| | ;--' | Mail: elke@jlab.org Mobil: 001-757-256-5224 -
'--' `-.--. | +
\_ | |---' Tel.: 001-757-269-5352 =
`-._\__/ Fax.: 001-757-269-6331 -
+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+=-+