Re: TOF PMT Mounting was: Re: Design drawings

[Elton Smith <elton@jlab.org>]

Hall D PID Mail List:


Concerning the width, just a caution that increasing the width will likely
reduce the amount of light collected and therefore impact the resolution.
Achieving the best possible resolution continues to be our goal, so we
need to keep that in mind while working on the mechanical design.

Cheers, Elton.



Elton Smith
Jefferson Lab MS 12H5
12000 Jefferson Ave
Suite # 16
Newport News, VA 23606
elton@jlab.org
(757) 269-7625

On Mon, 16 Apr 2007, Alex Dzierba wrote:

> Hall D PID Mail List:
>
> There is nothing sacrosanct about 6.000 cm - we could go to a comfortable
> enough width to give us some wiggle room with little danger of
> running into occupancy problems or degrading timing.
>
> At 4:58 PM -0400 4/16/07, Matthew Shepherd wrote:
> >Hi Alex and Tim,
> >
> >I'm attaching a mechanical drawing for the VD124K bases that we plan
> >to use in the TOF.  You can see that the socket seems to have 56.5
> >mm diameter.  With a 60 mm bar width, this leaves 3.5 mm between
> >bases in an "inline design" -- tight.  Also there is a "loose
> >flange" that would definitely interfere in an inline design, but
> >maybe could be removed from the base.
> >
> >Some of the same challenges with FCAL are present here.  We need a
> >design that allows replacement of tubes.  The big plus here is that
> >we have almost 20 times fewer channels to deal with.
> >
> >-Matt
> >
> >
> >
> >Content-Type: application/pdf;
> >	x-unix-mode=0644;
> >	name=Vd124k.pdf
> >Content-Disposition: inline;
> >	filename=Vd124k.pdf
> >
> >Attachment converted: Macintosh HD:Vd124k 1.pdf (PDF /prvw) (001926CE)
> >
> >On Apr 13, 2007, at 2:45 PM, Alex Dzierba wrote:
> >
> >>Tim and I just talked.  Before we did I found the attached drawing
> >>by Eric that shows a tapered scintillator bar that has an active
> >>length of 2 m, a width of 6 cm and a thickness of 2.54 cm.  The
> >>ends are tapered to accommodate the XP2020 (2-in diameter)
> >>and shielding.  Note Eric's units are inches.   The difference
> >>now is to have a 2.52 m active length.  The two-wall structure
> >>has a 12 cm x 12 cm hole with the center bars being less than
> >>half-bars with readout at only one end for these bars.
>
>
> --
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Alex R. Dzierba
> Chancellor's Professor of Physics (Emeritus)
> Department of Physics / Indiana U / Bloomington IN 47405 / 812-855-9421
> JLab Visiting Fellow
> Jefferson Lab / 12000 Jefferson Ave / Newport News, VA 23606 / 757-269-7577
> Home Phone: 812-825-4063  Cell:  812-327-1881  Fax: 866-541-1263
> http://dustbunny.physics.indiana.edu/~dzierba/
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>