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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.

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?

>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?

>
>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.


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/
>>
>>
>>
>>    
>>
>
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> |       `,              Elke-Caroline Aschenauer            =
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