Re: Moving forward on FCAL design and prototype

[Tim Whitlatch <whitey@jlab.org>]

Hi Matt,

This sounds  reasonable overall..

One thing that was brought up in the calorimetry review was the 
dimensional stability of the plastic cell wall. I have started to 
inquire plastic machining houses but have not got answers yet. It may be 
good for John to pursue this and see which plastic would work best and 
the stability during machining.This should be first.

It would be great to try a small stack with the present concept to see 
if improvements or changes need to be made.

The dark room can be worked as the cell wall is finalized.

I have looked at the Primex cell wall design. It incorporates copper or 
brass wrappings soldered around each block with the PMT's attached to 
each block The advantage is that the PMT always lines up with and 
travels with the block. This was a very labor intensive job and I 
believe would be more difficult than the cell wall. There will also be a 
dead spots (1-2mm) between each block by virtue of the design. We can 
look further into this if desired.

Let's have a phone conversation after the drift chamber review.

Cheers,

       Tim

Matthew Shepherd wrote:
>
> Hi Tim,
>
> John is getting settled in and we would like to keep moving forward on 
> design and prototyping of the FCAL and want to make sure we are doing 
> so in a way that consistent with deadlines that you might have 
> regarding CD-3.  There are several things on our list:
>
> - build a prototype circular stack of glass using the concept that you 
> proposed for the final stack
> - work on design/drawings of the dark room
> - finalize cell wall design
>     - we are waiting on another batch of softer/thicker cookies
>     - we should also probably try to construct your proposed threaded 
> design
>     - we want to consider the design used by Primex that Dave Cashy 
> came up with -- apparently the tubes and electronics are strapped onto 
> the block using thin metal straps that go in between blocks instead of 
> having a single monolithic structure to hold the tubes.  I'm trying to 
> talk with the Primex guys to get some drawings
>
> Are there particular items that you see as high(er) priority that are 
> needed to satisfy deadlines related to CD-3?  We'd be happy to arrange 
> a phone chat sometime if you felt that was helpful.  Also if needed, 
> we can come down for a day sometime in the future and talk about 
> specifics in person.
>
> Cheers,
>
> Matt
>
>
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